Iguana Dissertation

1 | Dissertation on Iguana | IACG 1 | Dissertation on Iguana | IACG

DISSERTATION ON IGUANA

TEAM MEMBERSS.Sai DasM.RohiniY.S.AdityaS.Sandeep

http://www.youtube.com/watch?v=RnBUOX9M2BM&feature=BFa&list=PLED5E234FBC30A8D5

2 | Dissertation on Iguana | IACG

OBJECTIVERecreate Iguana in CG with photo-realistic look, which includes anatomy, behaviour, Movements. And integrate seamlessly into live action footage.


• How many types of species exist?• Distribution and habitat• Where can we find them ?• Differentiation of gender based on their apperance

CONTENTS

• Evolution• Entire history• Mythological status• Social role

History of Iguana

Biology of Iguana• Size and Measurement• Life Span• Colors and Markings• Reproduction and Development

• Skeleton system and naming• Eye,Moth and Ear systems• Muscular system and Movement

Species of Iguana

Anatomy of Iguana


Movement• Walk cycle• Movement of tail• Influence of bones on muscles when it moves• How it defends

Behaviour• Feeding behaviour• Senses and Response• Intelligence at learning

Conservation watch• Endangered• Critically endangered • Vulnerable

Modeling and TexturingRigging and Animation

Lighting and Compositing

Matchmove and Rotoscopy


Evolution

• The species was first officially described by Swedish bota-nist Carl Linnaeus in 1758.In the two centuries since then, no less than 17 species and subspecies have been identified with all but one species (Iguana delicatissima) being found to be invalid.

• Using nuclear and mitochondrial DNA-sequence data to explore the phylogenic history of the green iguana, scientists from Utah Valley State College studied animals collected from 17 different countries. The topology of phylogeny indicated that the species originated in South America and eventually radiated through Central America and the Caribbean. The study revealed no unique mitochondrial DNA haplotypes for sub specific status but did indicate the deep lineage divergence between Central and South American populations.

History


Etymology

• The name iguana is derived from the Spanish equivalent to the Carib Indian name “iwana”. The green iguana is a reptile and is cold blooded. This means that the animals do not create or maintain their own body heat. To warm up they must find an area that is warm or to bask in the sun to warm up their body. In some Spanish speaking countries, males of the species are referred to as gorrobo or ministro and juveniles are called iguanita or gorrobito.• Reptiles have one advantage over birds and mammals, at least in the Caribbean. They do not need to maintain a constant body temperature and therefore need less food. As a result they can survive in habitats such as the dry east end of St.Thomas and St. Croix, where food is limited.• The most obvious feature of iguanas is their dry scale covered skin. This covering of scales reduces water loss and may facilitate the uptake of solar energy.


• Wild green iguanas are found naturally in southern Mexico, Central America, and most of South America. A few are found on the Lesser Antilles islands, along with I. delicatissima.• Feral populations can be found in parts of California, Florida and Hawaii. These populations consist of individuals that either escaped from captivity or were purposefully released by their owners, and which have survived and even thrived and bred in this new habitat. Although many people may think that such populations of non-native species add to the variety of the environment, they are, in fact, quite harmful to native species. They disrupt the ecosystem, compete with native species for resources, and prey on species that are not adapted to deal with such predators. Iguanas that are introduced to new areas are no different. In fact, it is illegal to own pet iguanas in the state of Hawaii, because the isolated island ecosystems are so easily disrupted by the introduction on exotic, or non-native species. Despite this, feral populations of iguanas do exist there. Populations of feral iguanas in Florida cause much damage and frustration each year. Owners of pet iguanas must be responsible for their pets, and make a conscious effort to prevent them from entering the wild in areas where they are not native.

History


In their native habitats, green iguanas are found mostly in the rainforests, although some do live in drier, costal areas. They tend to limit themselves to lower altitudinal regions, where temperatures are warm enough for their ectothermic lifesyle. The photo below of a wild baby iguana was taken in Mexico.

Social role• Native people often refer to green iguanas as “the chicken of the trees”, or “bamboo chicken”. • Green iguanas are harvested for their skin, meat and eggs. The time of year for iguana mating season varies from region to region, but it tends to fall in the months of January

and February. • Wild, gravid females are captured and their eggs are collected for food and to supply “iguana farms” with babies for the pet trade. • While small-scale hunting is not a threat to iguana populations, large-scale harvesting, particularly to supply the pet trade, is.Although large-scale hunting and egg-collecting activities threaten wild iguana populations, the biggest threat to the wild existence of these lizards is habitat loss.


• As the rain forests disappear, so to do green iguanas. Although they are not currently listed as threatened or endangered, they are certainly at risk, along with all the other inhabitants of these forests. • Iguanas are farmed in some countries as a source of food and leather, as well as for the pet trade. Due to their large size, iguana hides provide a source of luxury leather that can be made into boots, belts or purses. • The pet industry also prizes iguanas; most are sold in the United States, Europe, and Japan. Iguanas also make an interesting tourist attraction in resort areas. • In addition to helping disperse seeds, iguanas provide a source of food for larger predatory animals, including humans. Like other amphibians and reptiles, iguanas can be indicators of environmental changes.• Reptiles are more sensitive to environmental changes than are humans, and by watching their responses, we can be alerted to possible problems before they are large enough for us to detect with our own senses Happily, sometimes wild iguanas can benefit from and enjoy the company of people.


Types of species

Species of Iguana

• There are many types of Iguana like Green Iguana,Marine Iguana,Desert Iguana,Rhinocerous Iguana,Pink Iguana and Blue Iguana.• The most common ones seen in the home as pets are the green iguana.• These are best suited to life with humans because of the different types, they are a good size brightly colored and their characteristics are good natured – compared to other iguanas, and easy going. But they can be demanding to care for and need attention from their owners.


Green Iguana• The Green Iguana or Common Iguana (Iguana iguana) is a large, arboreal herbivorous species of lizard of the genus Iguana native to Central and South America.• The green iguana ranges over a large geographic area, from southern Brazil and Paraguay to as far north as Mexico and the Caribbean Islands; and in the United States as feral populations in South Florida (including the Florida Keys), Hawaii, and the Rio Grande Valley of Texas.• A herbivore, it has adapted significantly with regard to locomotion and osmoregulation as a result of its diet. • It grows to 1.5 metres (4.9 ft) in length from head to tail, although a few specimens have grown more than 2 metres (6.6 ft) with bodyweights upward of 20 pounds (9.1 kg). • Commonly found in captivity as a pet due to its calm disposition and bright colors, it can be demanding to care for properly. • Space requirements and the need for special lighting and heat can prove challenging to an amateur hobbyist. • The Green Iguana or Common Iguana (Iguana iguana) is a large, arboreal herbivorous species of lizard of the genus Iguana native to Central and South America.


Where can we find them?

• The green iguana ranges over a large geographic area, from southern Brazil and Paraguay to as far north as Mexico and the Caribbean Islands; and in the United States as feral populations in South Florida (including the Florida Keys), Hawaii, and the Rio Grande Valley of Texas.

• Green Iguanas come from the forests of Central and South America. Because they like warmth and sunshine, they live in the trees at the edge of the jungle and in clearings. Iguanas are active in the day-time and sleep at night.• There, they can be seen sunning

themselves on large tree branches or feeding among the tree leaves. Iguanas are very territorial. A single large male guards a territory not much bigger than a residential lot and it will run off any other adult males that are in sight. I watched this, growing up near Tampico, Mexico.


Distribution and habitat• The native range of the Green Iguana extends from southern Mexico to central Brazil, Paraguay, and Bolivia and the Caribbean; specifically Grenada, Curacao, Trinidad and Tobago, St. Lucia, St. Vincent, and utila. They have been introduced to Grand Cayman, Puerto Rico, Texas, Florida, Hawaii, and the United States Virgin Islands.• Green Iguanas are diurnal, arboreal, and are often found near water. Agile climbers, Iguana iguana can fall up to 50 feet (15 m) and land unhurt (iguanas use their hind leg claws to clasp leaves and branches to break a fall).During cold, wet weather, green iguanas prefer to stay on the ground for greater warmth. When swimming, an iguana remains submerged, letting its four legs hang limply against its side. They propel through the water with powerful tail strokes.• Because of the Green Iguana’s popularity in the pet trade and as a food source in Latin America, they are listed on the CITES Appendix II, which means that while they are not an endangered species, “their trade must be controlled so as to not harm the species in the future”.• They get heat from their environment. Their bodies use certain wavelengths of light in the environment to aid in their metabolism and body chemistry.


• They are very well adapted to their natural environment (warm, fairly humid places), which is usually extremely different from the captive environment in which they find themselves.• What this means is that, unless you can create an environment for them that provides these things that they need, they will suffer, become ill, and maybe even die. Understanding your iguana’s needs before you create a habitat for it is very important.

Differentiation between genders of Iguana based on their

apeearanace

• You cannot tell the sex of a baby iguana by looking at it. The iguana will have to be over a year and a half old (8-10 inches long) before males begin to look differently than females.• Once they do begin to develop, male iguanas become more ornate and “flowery” than females. Their jaws becomes stouter and broader. Their heads become broader and they develop a dewlap or “jowls”. The round scale covering their eardrum becomes larger and more prominent than in females.• Male iguanas also develop longer crests along the ridge of their spine and large pores on the inner surface of their thighs. They also become wider in the pelvic area.


• If you look at the face of an adult Iguana you will notice a very large round scale. In females the scale is flattish, in males this develops fatty deposits and begins to look like Jowls. Also fat deposits will develop over the top of the head , females heads look smooth and rounded, males develop 2 distinctive bumps on top of the head.• Look at the underside of your Iguana’ s hind legs in the upper Thigh area. You will see a row of pores on each leg. In females this row of pores is very tiny, almost pin-pricks. In makes the pores can become quite obvious almost looking like a comb with it’s thick waxy exudates• Juveniles of both sexes look alike and will not show any secondary sexual characteristics until they reach maturity. Sexual maturity in iguanas is a function of size rather than age. Males may become sexually mature once they reach 6” SVL(Scientific Vector Language).• Females will usually take a bit longer, and will not mature until they reach about 10” SVL. Depending upon the care of the iguana, its age at maturity may vary a bit, but it usually falls somewhere in between 1.5 - 2 years.


Physical characteristics of Male

Male iguana

• At maturity, males show several secondary sexual characteristics. One of the most easily identified is the large jaw muscles on either side of the lower jaw, below the ear. These muscles produce large, swollen-looking “jowls”. Males have large, blocky heads, and the jowls add to this effect. Males also have two fatty deposits on

their foreheads, behind the eye and above the ear. These also add to the size and blocky shape of the head.• Notice the fatty bumps behind the eye and above the ear. You can also see Jake’s jowls, with the large subtympanic shield scales • Males also tend to have longer dorsal spikes along their back, especially along the neck area. Another indication that an iguana is a male is the large pores that are visible along the inner thigh. These pores, called femoral pores, are easily visible in males, and are often filled with a waxy substance. •Two other male characteristics are a heftier, heavier body and a bulge near the base of the tail where the hemipenes are located.


Physical characteristics of Female

• Physical Characteristics - The easiest way to identify a female iguana is by the absence of male secondary sexual characteristics. Their heads are smaller and more streamlined, and lack the fatty deposits behind the eyes and the more pronounced jowls.• Her head is smaller. Notice that she lacks the fatty deposits and the larger, more pronounced jowls.• In addition to having smaller heads, females also have small femoral pores which do not develop waxy protuberances.• Females tend to have longer, slimmer bodies than males and lack the hemipenes bulge near the vent.

Female iguana


Life span of Iguana

Extreme life span (captivity)

Average life span (wild)

Average life span (captivity)

20 years (high)

8 years

10 years

Size and Measurement

• The iguana will have outgrown commercially available enclosures.• That enclosure will be at least 6 feet (1.83 m) tall, and the depth at least 3 feet (0.92 m) deep (front to back). The width (side to side) needs to be at least 1.5-2 times the• iguana’s projected overall length over the life of that enclosure. • An iguana grows up to 1.5 meters (4.9 ft) in length from head to tail, although a few specimens have grown more than 2 meters (6.6 ft) with bodyweights upward of 20 pounds (9.1 kg). A full grown iguana is one of the largest arboreal reptiles, reaching 6 or 7 feet in length. The length of green iguanas ranges from 17 to 25 cm. Most mature iguanas weigh between 4 and 6 kg, but some in South America, with proper diet can reach up to 8 kg. These large lizards can reach head to tail

Biology of Iguana


•Iguana iguana is commonly called the “green iguana”, not all members of this species are green. Healthy baby iguanas tend to be bright green or greenish-blue in coloring. However, as they age, most iguanas lose this bright coloring and end up with a duller green/gray/brown or even orange coloring with brown or black markings.•This is completely normal and should be expected. Even the so-called “Blue Diamond” iguanas (sold in pet stores under the Fluker brand name) will eventually lose some of their bright baby coloration. Coloring in adult iguanas varies according to their country of origin. • According to Melissa Kaplan, author of Iguanas for Dummies, iguanas from Mexico tend to show brownish-orange coloring in males on the legs, while the body remains green. Iguanas from Central America are often pale green, with light blue/white heads and bold black or brown belly stripes.

Colors and markings


• Mature adults often display some orange coloring all year, especially in males. South American iguanas often retain blue coloration. Since all baby iguanas share the same bright green coloring, it is always a surprise what you’ll end up with once your iguana matures.• It is a commonly held belief that green iguanas can change color like chameleons can. However, this is not accurate. Iguanas are capable of color changes, but only in specific situations. Some situations deal with stress, others with breeding issues, and some simply because the iguana is basking in the sun. • One of the most obvious color changes in the iguana is when it is taken outside for some real sunlight. Most iguanas immediately become dark. Their heads turn dark grey, almost black for some individuals, and the stripes on the iguana’s body become very apparent. Many iguanas have brown marks that appear on their back that are never seen inside, and give the iguana a sort of leopard-like markings. • The reason they darken is because dark colors absorb more of the sun than light colors do. It’s like wearing a black t-shirt on a very hot day com-pared to wearing a white t-shirt. The white t-shirt reflects the light better; the black t-shirt absorbs it more. You also feel much hotter in the black t-shirt. When the iguanas start to feel too hot, they lighten up their color-ation. This helps them thermo regulate when they are in the sun.


• An iguana that is indoors and is too cold may also have a dark-grayish coloration. As explained above, this is an attempt to absorb more heat from the environment. If the temperature of the iguana’s environment is raised to appropriate levels, the color will again lighten. The types of lights used in an iguana’s enclosure may also affect its coloring. Different types of lights reflect differently off the iguana’s skin and can enhance or change the ap-pearance of the iguana’s color while they sit under the bulbs. Some lights, such as mercury vapor bulbs, have a reputation for actually causing an iguana’s skin pigment to brighten so that its color is enhanced even when it is not directly under the light. Reports of this effect vary.• Stress can produce a colorful array of shades that you would never nor-mally see on an iguana. Each iguana responds in its own way regarding color changes due to stress.• An iguana belonging to one of the GIS Team members lightens the color on her head until it is a pale grey, and blue-green spots occur in various areas on her head. The color on her body turns a bright yellow-green, which obliterates the normal bits of bright blue that she has on her body. Once the source of stress is gone (usually a trip to the veterinarian), she slowly returns to her normal colors. A second iguana belonging to another GIS (green iguana society) Team member exhibits a color change that turns her head bright white when she is stressed and/or afraid. In yet a third iguana owned by a GIS Team member, stress produces a very dark, almost black coloration on the head and a darkening of the body.


• Breeding season produces many color changes in both male and female iguanas. The most notable one is the orange color that males develop as they enter their season. • It generally starts on the legs, and the shade of orange can actually vary from a light orange to a very bright, almost neon orange.• The color can also change on the sides of the iguana’s body, as well as the tail. The coloration can last for a few months, as that is the normal length of iguana breeding season. Females may also develop some orange coloration, but rarely to the extent that males do. Generally the color fades as the iguana’s breeding season ends, but some iguanas retain the coloration and always have some orange on them. This is more common in males.• The worst color change an iguana can have is when it is sick. Generally, when you go to the pet store and you look at the iguanas, you can spot the sick ones right away.• They tend to be brownish in color, and show other signs of illness such as lethargy. Your own iguana can get that brownish color if it gets sick enough before you take it to the veterinarian. A well-cared-for iguana that is slightly sick may simply appear not as vibrantly colored as normal. Although orange hues are normal for some iguanas, they are sometimes a sign of severe dehydration or kidney disease. If orange coloring appears suddenly in an older iguana and is not associated with breeding season, a veterinary visit is recommended.


• Green Iguanas reach sexual maturity between three and four years of age. Iguanas breed in the dry season, ensuring that young hatch in the wet season when food is more readily available.• Iguana females can lay 20-70 eggs at a time. Females deposit eggs approximately 65 days after mating, usually over the course of three days, into nests excavated to a depth of about 1 to 3 feet into the soil. Incubation takes 90 to 120 days. Young Iguanas are independent from the time of hatching.

Reproduction


Development

• Most green iguanas reach sexual maturity between three and four years of age, although maturity can be reached earlier. Iguanas tend to breed in the dry season, ensuring that young hatch in the wet season when food is more readily available.• Mating appears to be polygynandrous. Courtship occurs within a defined territory where more than one female may be present. Conflicts between males are not uncommon. Courtship behavior of males includes head bobbing, extending and retraction of the dewlap, and nuzzling or biting a female’s neck . Dominant males may also mark rocks, branches, and females with a waxy pheromone-containing substance secreted from their femoral pores.•During mating, the male approachs the female and climbs on her back, straddling her. To restrain his mate, he grips the her shoulder skin with his teeth, sometimes causing wounds. The male then pairs his cloacal vent up with the female’s and inserts one of his hemipenes into her cloaca. Copulation can last for several minutes. Female iguanas can save sperm for several years , allowing them to fertilize eggs at a much later date.• Females lay their eggs about 65 days after mating (eggs take 59 to 84 days to develop before they are laid).


• Over the course of three days, females may up to 65 eggs, each measuring around 15.4 mm in diameter, and 35 to 40 mm in length (Frye, 1995). Eggs are deposited into nests which are located 45 cm to more than a meter deep, and may be shared with other females if nesting areas are limited.• Incubation lasts from 90 to 120 days. Temperature should range from 85 to 91 degrees Fahrenheit. The hatchlings pip the egg open using a special egg tooth, called the caruncle, that falls off shortly after hatching. Absorbed yolk provides most of the nourishment for the first week or two of an iguana’s life. Young are independent from birth. • Timing of sexual maturity varies. Animals may be able to breed as early as their second year, but may not breed until as late as their fifth year. (Frye, 1995• Parental investment includes the risk of mating and laying eggs. Eggs are provisioned with nutrients by the mother. Females choose nesting sites, presumably as a means of caring for their offspring. However, after eggs are laid, there is no direct investment in the young.


•These animals breed annually.

• Green iguanas breed in the dry season

• 65 (high); avg. 20

• 59 to 84 days; avg. 65 days

• 2.50 to 5 years; avg. 3.50 years

• 3 to 5 years • Approximately 65 days after mating, a female is ready to lay her eggs. The size and number of eggs produced varies depending upon her size, her nutritional status, and her maturity

Breeding interval

Breeding season

Number of offspring

Gestation period

Age at sexual or reproductive maturity (female)

Age at sexual or reproductive maturity (male)


• Eggs measure around 15.4 mm in diameter, and 35 to 40 mm in length. Over a three day period, an average of 10 to 30 leathery white or pale-cream colored eggs are deposited into a nest. Nests are located 45 cm to more than a meter deep, and may be shared with other females if nesting areas are limited. After laying the eggs, females may return to the nest several times but do not stay to guard it.

• Incubation lasts from 90 to 120 days. Temperature should range from 85 to 91 degrees Fahrenheit. The hatchlings pip the egg open using a special egg tooth, called the caruncle, that falls off shortly after hatching. Absorbed yolk provides most of the nourishment for the first week or two of an iguana’s life. • There are no major morphological changes in these animals as they age, except that they grow. However, diet is related to age. The young, with higher need for protein, are more likely to consume insects and eggs than are mature individuals.


Anatomy of Iguana

• The two species of lizard within the genus Iguana possess a dewlap, a row of spines running down their back to their tail, and a third “eye” on their head. This eye is known as the parietal eye, visible as a pale scale on the top of the head. Behind their neck are small scales which resemble spikes, known as tuberculate scales. These scales may be a variety of colors and are not always visible from close distances. They have a large round scale on their cheek known as a subtympanic shield.• Iguanas have excellent vision and can see shapes, shadows, colors and movement at long distances. Iguanas use their eyes to navigate through crowded forests, as well as for finding food. They use visual signals to com-municate with other members of the same species.• The tympanum is the iguana’s ear drum, and is located above the sub-tympanic shield and behind the eye. Iguanas are often hard to spot, as they tend to blend into their surroundings. Their scale colors are a mode of hiding from larger predators.• Male iguanas, as well as other male members of the order Squamata, have two hemipenes.


• These two photos show that iguanas do have many very sharp teeth. These photos are provided to not only show you what iguana teeth look like, but to serve as a warning when dealing with large, aggressive iguanas. Iguanas have many very sharp, jagged and dangerous teeth that are very capable of shredding leafy foods, as well as human skin! The photo on the right is also an excellent view of an iguana’s tongue.

• The following photo here defines various parts of the head and upper body.


• The photo below shows the parietal eye. The parietal eye is a tiny, transparent scale on the top of the head that detects light and dark. Igua-nas use the parietal eye to alert them to aerial predators. It is sometimes referred to as the third-eye.


• Tuberculate scales are small tubular spikes that protrude behind the tympanum, above the front limbs and can come in a variety of colors.

• Iguanas have good hearing and can pick up sounds best in the 500 - 3,000Hz range

• The jowls are skin and muscle that seem to “hang” on either side of the head. Males have significantly large and more defined jowls than females do. The presence of enlarged jowls is used in Sexing Iguanas

Tuberculate scales

Tympanum (Ear)

Jowl


• The subtympanic shield serves little purpose. It is possible its large size would help dissuade predators by fooling them into believing it is a large eye or it may help to break up the iguanas shape amongst the trees

• An iguanas dewlap is a flap of skin under throat.

• The iguanas mouth is lined with small teeth designed to shred vegetation. These same teeth are capable of lacerating human flesh extensively.

• The nostril of an iguana is used to breathe and expel excess salts as a result of their digestive process.

• The rostral horn can appear alone or in a set of 2 or 3 and are not found on all iguanas. They can also be different sizes.

Subtympanic shield

Dewlap

Mouth

Nostril

Rostral horn


• The protrusion, or “ridge” above the eye

• Iguanas have very keen eyesight and can see shapes, shadows, colors and movement at long distances

• The bumps on an iguanas head are not truly “brain bumps”, they are actually fatty deposits that are a characteristic found in male iguanas

• An ornamental projection of small spikes found on the back of the neck (nape), behind the fatty deposits

• These are the spines that run along the ridge of the back and tail. These spikes may serve more than the purpose of simply making the iguana an attractive species

Eye ridge

Eye

Brain bumps

Nuchal crest

Caudal spines


• Germ cells, formed while the iguana is still an embryo in the egg, ultimately become either ova (eggs) or spermatozoa (sperm), depending on the sex of the iguana. During this time, the testes of the male iguana, already larger in relation to body mass than those of other animals, begin to enlarge as sperm is produced and stored.• Iguana ovaries and testes are tucked up well inside the torso of the iguana. The annotated drawing below is a little misleading as the testes and ovaries lay behind the liver, as one sees it when going into the coelomic cavity through an abdominal incision, as one does when spay-ing or neutering an iguana. The ovaries and testes are paired, attached by the mesovarium and mesorchium, respectively, to the left and right sides of the dorsal wall. The adrenal glands are embedded in the mesovarium and mesorchium mesentery as well.

• In females, the ovaries are an almost insignificant dark gray mass that is nestled up against the middorsal wall of the body cavity.• Outside of breeding season, the mass looks like a dollop of caviar. During breeding, the tiny germ cells in the ovaries begin to enlarge. Estrogen triggers the liver to start converting lipids in the stored body fat to vitellogenin.

Reproductive system

Ovaries


• As the vitellogenin is circulated through the bloodstream, the enlarging egg follicles absorb the vitellogenin, which is stored in the ova as yolk.Each oocyte (individual single-cell) is enclosed in its own membrane; each ovary consists of a group of oocytes contained in an overall membrane. Fertilization occurs while the early developing eggs (secondary oocytes) are still in the ovaries. After fertilization, yolk development continues (vitellogenesis), with the ova continuing to grow, until the mature ova are 10-100 times their pre-vitellogenic size (depending on species)

Reproductive system


• “Ovulation” is the rupture of the individual and overall ovarian membranes as the eggs are freed from the enclosing membranes. As the egg passes through the nearby oviduct (one for each ovary), layers of fibers and proteins are applied to each egg (with each layer being applied at specific points within the oviduct), with the final layer being calcium carbonate (calcite crystals in crocodilians and squamates; aragonite crystals in turtles). The oviducts empty into the cloaca, thus eggs are shelled just before they are actually laid.

Testes

• Male iguanas are fully equipped with two testes and the hemipenes, the bi-lobed copulatory organ. The testes are inside the body, in the same position as the ovaries, behind the liver, while the hemipenes are tucked inside the base of the tail (which explains why male reptiles have broader tail bases than do females of the spacies).


• Male iguanas have the largest testes for their body size of all reptiles. • Iguana testes comprise 1% the male iguana’s body mass. • By comparison, the great apes have testes ranging in size from 0.017% to 0.269%. The great apes, then, have one-fourth as much testicular tissue, relatively speaking, as do the green iguanas. (Human males come in somewhere in the great apes range, with a 6’0” 180 pound human male having testes weighing in at about 0.041% of body weight.) Iguana keepers who have had occasion to clean up iguana ejaculate are not surprised by this datum.

Skull

Iguanas have a wide mouth containing very sharp teeth, the nostrils from which they often snort out unwanted salts, two ears which look like recessed scales each side of the head, these are actually external ear drums , and two eyes, well two eyes as we know them, but actually Iguanas have what is called a third eye on the top of the head (parietal eye) also sometimes referred to as either the third eye , pineal eye, or pineal gland, this is linked to a sensor or retina that does not focus like the normal eyes but seems to be for detecting movement from above, perhaps as an early warning system against predators which in the wild would mainly be birds of prey.


• The Dewlap, under the chin and the Sub Tympanic Scales under each ear, The Dewlap seems to have two purposes, It is flared out when feeling threatened or showing off, so as to make the Iguana appear bigger, along with this they will usually stand up higher and raise their head up in the air, so as to appear altogether larger, but also because of the blood vessels it contains, it can be flared out when absorbing heat from the sun to help with thermoregulation, it is also waved around during head bobbing sessions. The Sub Tympanic Scales appear only to be decorative, although from a distance to a predator they could look like large eyes and with the dewlap extended can appear to make the Iguana appear much bigger than he really is.• The main obvious items to notice along here are the spines or crest, this starts off as the nuchal crest on the neck, which joins on to the dorsal crest along the back, then down to the caudal crest which follows on part way along the tail, These can sometimes become damaged or have the odd one or two spines missing, and they can also be re-grown to a certain extent, but do not usually grow back to the full size. They are also usually bigger in a male Iguana, but this is not a guaranteed way to sex an Iguana.


• Scales, (basically skin cells) which are not as elasticated as in mammals, these have to be shed to let the new ones underneath take over, this is a normal process and also a sign that the Iguana is growing. (snakes shed all in one go, many lizards shed only parts at a time, and mammals shed almost unnoticeably minute particles all the time) Crocs by the way, shed very similar to humans! Bones, The Iguana as with other reptiles / animals, has a normal skeletal system, but to make good use of calcium they need to also have vitamin D3 which they can make if they have sufficient exposure to sunlight combined with good diet, which in captivity is not always the case. This is why they have to have a good reptile light capable of emitting UVB rays, these mimic sunlight to an extent, also note: reptile tubes can start to deteriorate after a period of 6-12 months and so should be replaced after this period of time. • There are a few types of indicators that have recently come onto the market, that measure the UVB given out at a set distance, they can not only save money by preventing the throwing away of tubes that still have life in them, but also helps maintain an healthy Iguana.

Skeleton


Concept

A guy will be sitting at the bank of the pond.He brings fruits in a basket .Seeing these fruits an Iguana crawls down the trunk of a tree and comes down near the basket placed beside the guy.Suddenly Iguana touches his hand .Both the guy and Iguana will be scared and it runs away.


Story board


Modeling and texturing

Front view

Side view

3/4 th view


• We started by taking the pictures of our character Iguana at the Zoo. We shot some videos for reference.Then as a modeler i needed some more images showing each and every part of Iguana in detail.So i collected as many references i could from internet for eyes,mouth,legs andbody.Then to know the shapes properly,i collected images of skeleton.


• For the model sheet i used images as reference for getting front and profile views for head...the front view was difficult to get but I got it from taking the print screen of the video we shooted in the zoo. It is blurred so I had to keep checking the refernece images for detail.

Model sheet

Model sheet


• Then for body, legs,and tail i used one picture as an image plane for proportions to be maintained properly.This pic was scaled to 3cm in maya as the average size of Iguana was 3 feet where the tail covers 2/3 part of the whole character.

Reference image for side view


Eye

Modelling

• I started with eye ,probably the difficult part to model but the most attractive part too.The main issue with the eye was that it had folds so I had to be careful as no vertices overlap each other.

• After the eye was done, i Started modelling the nose part of iguana. The profile and the front image planes helped in getting the shape of the front head properly .


• The upper part of the head was done and then I started modelling the lower part, the jaw and the thing to take care was the mouth line which was not straight, which came out pretty good.

Nose

Mouth


• As modeling the head part was over.I started modeling the body part.Here I used another image plane for the profile view of the body and to maintain the proper proportions. Initially I roughly modelled the legs with the body.

• As I was modelling the body I had to refer to the top view in reference images as the body was fatter in the middle part an it gradually went thinner when it came to tail and legs.

Hands

Body and tail


• After the basic construction of the body was done the legs had to be modeled in detail.For the reference I used the leg part frm each image n combined all those references in to one image and I used the skeleton images of front leg ,so that I get a clear idea of the length and proportions of the fingers joints and the elbow joint

• Modelling the back legs was the toughest as the back leg had fingers with the different lenghts and the reference images were also few. I used the one image which had the references of back leg ,and I had to model it.

Fingers of hands

Fingers of legs


• Then the other part left to be modeled was spikes on the dorsal side, which i modelled it straight and then bent them randomly for giving it a natural look. Initially I thought of using lattice for bending the spikes but it was nt flexible enough. So I bent each and every spike manually.

• Then for modelling the mouth ,tongue, teeth, i took the help of rigging to open the mouth of the model. Here I duplicated the jaw faces from the intial model of the head such that I get a base to built on. The teeth of Iguana are flat and thin which i modelled by observing some reference pictures.

Spikes are modeled


• After modelling all the different parts and combing them,the model came out good.

Mouth

Final model


• Now i exported the model as .obj....then for unwraping the model i used Headus uv Layout,where i imported the .obj file and unwrappd the model.I used 3 uv sets,for head,body and legs

UV Unwrap


• Now the model was ready with uv s unwrapped.then i went through the basic checklist and sent it for rigging and skinning. As the rigging part was started i started the texturing part.Initially i broke up the body into 3 parts Head,legs and body,based on the 3 uv sets and exported each of them as .obj. I used Mudbox for texturing.Now i started preparing stencils for each and every part of the body taking diferent reference images.

Stencils


• After the stencils were done i started sculpting the head. I had to roughly sculpt out the scales ,then I used the grab tool to make the scales bulgy and look natural. The main difficult part was eye where in a small place it had a higher level of detail,which was done with the help of separate stencils which I made specially for the eye part and it did come out well.

Head sculpted in Mudbox


• I modelled the head which was like the most attractive part.The next part to sculpt was the scales on the body.Intially I thought of using stencil with hexagons but it will give a mechanical look so I have to prepare the stencils from the images in order to get scales in a random manner,which really worked out well and the scales were looking natural.

Body sculpted in Mudbox


• After sculpting the body scales i started sculpting the legs part where the problem that came up was the mirror option stopped working on the front legs.So I had to sculpt the each leg seperately. Then the scales became large n I had to re sculpt the front legs for smaller scales.

Hands sculpted in Mudbox


• Now the sculpting part is done and it was the time for the color to be done....again i went back to reference images for colors of scales and the body as a whole.As ours was a Green Iguana the character has to be in green shades. So similarly to sculpting i started painting Head part.....

• After painting the head part, i started painting the body where I painted border for each and every scale which took almost 3 days to complete as ther were thousands of scales on the body.

Coloring face in Mudbox

Coloring body in Mudbox


• After painting of the body was completed, i started painting the legs.Again the same mirror problem came up for the front legs where I had to paint each and every leg seperately.

• So finally after the coloring was completed with sculpting the character looked good.

Coloring hands in Mudbox

Whole body colored in Mudbox


Extracting texture maps• After the texturing was done,the Normal map,Diffuse map,Displacement map,and the VectorDisplacement maps are extracted from mudbox.

Diffuse map Vector displacement map

Displacement map Normal map


• Then after all the maps are extracted,i imported them into maya using the shading network where all the maps are connected to their respective shaders.so now the model was finally ready with all the textures and was ready for lighting.

• As iguana has so much detail..it took long time..the eye part was the most complicated for modeling.But it came out good.• When i was to model the inside part of the mouth i tried opening the mouth just by selecting the vertices of the lower jaw,and rotating it. But the vetices of the neck were going inside the body.I used different ways to open it but the same problem was popping up.Then i sent the file to the rigging team mate to keep joints and skin the head part just to open the mouth.So finally i could get the character with the open mouth which made it easier to model the inside part,the teeth and tongue.• The major problem i came up was the relax tool in maya stopped work-ing on the model.Thank god that it stopped working whn most of the model was done.But i had to compromise on the tail region where i had to leave the harder edges which could have smoothened by the relax tool

Problems faced during modeling and texturing


• At the time of unwrapping the model in Headus UV layout, inorder to take out the seam problem,i tried to attach the legs to the body part.But when i did that some of the uvs were overlapping. So i had to keep the legs separate from body.• The other thing that came up during unwrapping was the body had to be separated from tail as the character was too long. Then again the seam would be there.• when i started with the texturing part, we had mudbox2011,and when i increased the level to 5,it used to crash,with an error report of,not enough memory.Even the uvs were not getting created in mudbox2011.• Both the issues were resolved when i started working inMudbox2012 version.• At the time of sculpting the front legs, the mirror option stopped working in mudbox, so i had to sculpt each leg seperately and even i had to paint each leg seperately.• Iguana has spikes on the dorsal side and on the head the spikes start and they gradually increse in size.I modelled the bigger spikes in maya ,but i wanted to do the smaller spikes on the head in mudbox using sculpt. I did create the spikes but when i extracted the displacement map,they came as the darker regions. and when i applied it on maya model i was not getting the spikes.


• The main problem was the surface of the head was like a slope not a plane,So when i was sculpting,the spikes also come in the slant position(not in 90degrees).But when u extract the map,which is a 2 dimensional output,there the tip of the spike overlap with the base as the spikes are not in 90 degress angle.So i had to leave the spikes and move on to the next part.• During the coloring part in Mudbox, when i tried painting in the same file in which i sculpted i was not able to move the view port easily as the software was getting slower due to heavier file.to counter this i extracted the normal map of the sculpted head and then i opened the new file of the head without sculpt and i imported the normal map• The other issue which came up was during rigging where the shape of the back leg knee was getiing deformed.Then i had to re adjust the edge loops, and the shape was not getting deformed now.


Rigging• I have started doing skeleton from the pelvis joint.• For the spine I took seven joints as it is very flexible.• Spine bends a bit if we check in side view it’s not perfectly straight.• Using more joints in rigging makes skinning easy because of proper sharing of weights.• We can even add the joints sideward in order to create the feel of respiration.• The skeleton structure for spine is done.• For tail I took 20 joints for free flexibility. No special features in tail. So normal skeleton structure is enough.• Whenever I move hip legs should also move or if I rotate hip control legs also should rotate with that control.• This creates the feel of weight shift.• I have taken COG joints in centre of spine joint and hip joint so that both spine and hip will connect to it and entire body moves if we move this joint.• Now we need to check the L.R.A properly.• We can directly use skeleton orient joint and select “xyz” in options and can orient the joints and use “none” option for the tip joints.


• Create ik spline handle, create clusters for ik spline curve vertices and in clusters weight node enter the name of control related to it.• In the same way tail is also rigged using ik spline handle.• Flexibility in spine and tail is proper.

Hands and legs rig

Basic skeleton structure

• Give the ik handle for hand.• Create wrist control, group it apply reverse point and orient constraints.• This helps us to match the orientation of joint with the control and as well as control group.• Give orient constraint from wrist control to wrist joint and point constraint from wrist control to ik handle.


Mesh with all controls

• We need to take pole vector control, and apply pole vector to it. This helps to adjust the position of elbow.• Add attributes for the fingers like twist, curl for each finger and spread.• We can use set driven key to add attributes for this. Driver is the main wrist control.

Attributes added for hands and legs


• In order to create the realistic look of spine, I need to create a rig in which the arc in the spine is automatically formed as we rotate the hip ctrl and chest control instead of adjusting all the spine controls.• I have added many joints to make skinning easy but in animation it was tedious to control. So to manage both skinning and animation we need to take 2 sets of joints , One for animation and other for skinning.• I used skin_set for skinning and FK _set for animation.• Fk joints are almost half of skin joints in same position.• This time in the weight node of cluster the name of control is not given but the name of fk_joint is given.• Give point and orient constraints from the control to fk joint.• This helps to both translate and rotate spine joints with less number of controls and good skinning.• For the tail only translation is given using ik spline handle .But the rotation is also needed .To create both translation and rotation we can take two set of controls, one for ik and other for fk..• In order to create the arc in spine automatically,select hip_ctrl,chest_ctrl,and group of one of the in-between spine joints and apply parent constraint switching on both point and orient in options.

Problems faced in rigging


• Now equally distribute the weights in attributes.• Now if we just rotate hip_ctrl and chest_ctrl, all the spine_ctrls will be set automatically.• Fingers were stiff in the previous rig setup. Now I have added curls for each fingers both front and sideward’s to bring overlapping feel in fingers

• Select the pelvis_joint, shift select the mesh and apply skin, bind skin, smooth bind.• Select the options joint hierarchy, closest to distance, classic linear, max influences “3”.• For the tail as I took many joints skinning was easy to do.

Skinning

Controls used to animate


Body skinning

Legs skinning

Hands skinning


• I have tried to bring out folds for body of iguana whenever it bends and be normal in normal pose but it was very tedious to manage both.• In order to bring that output I took blend shape of skin folds on each side separately and animate its value accordingly.• Skin near knees was problematic as the model is not in T-pose like other animals.• So separately correctives are needed to avoid the problem of penetration of skin near knees.• For mouth tongue, teeth and jaw was single object and it’s attached, when mouth is opened all the vertices of upper and lower teeth mixed together and jaw vertices are also mixed. Each and every vertex weight is checked in the component editor and skinned properly which took lot of time.•Due to less loops near the throat when we stretch the skin near throat using controls given the texture applied to it stretched so I again need to decrease the amount of stretch.

Problems faced in skinning

Mouth and teeth skinning


Leg before correctives are used

Leg after the correctives are used


• Animating iguana is interesting. I like the flexibility in its spine.Arc in the spine was bought easily after rig is modified.I have drawn key poses roughly and noted down the modifications taking place in each pose.After animating the main body, add the secondary animations like tail, skin near throat, and do eye blink animation.

Animation

Spine movement of Iguana


• In the dissertation of IGUANA all team members played their important role and made this project a success. We have divided the work between us according to our specilazations. Being a team member my part in this project is the visual effects part that is lighting,rendering and compositing. First the model was given to me without textures and shaders, to test the lighitng for basic lambert shader, I have used different lights on it for basic lighting test. After testing with default shaders. The character with out textures and default shaders will be as following :

Lighting and compositing

Character with default shaders


• Then I have showed the test lighting of the character to our faculties they have told the problems and they told to use sIBL type of lighting in whole project. So when we go to shoot of footage we have taken HDRI camera with us and we have taken and HDR image in proper environ-ment and proper lighting for the character to mix with bg. We have faced a problem for the first time we shot the HDR image. Then we have clearly known the settings and process to take the HDRI and then we re shoot the whole footage again with HDRI. We re shoot whole the footage because the lighting in environment changes day by day it may not match with the character lighting.• After HDRI is done we have used sIBl lighting by using the sIBL plugin in maya. When this whole process of shooting and HDRI is done the character is ready with textures. Then I have taken the textures and con-nected with uv sets and given the bump maps and vector displacement maps through the nodes in hypershade in maya. While connecting the maps I have faced some problems like not understading the connections properly where to give which connection. Then I have taken some of my friends help and then finally succeded in connecting all texture maps.• After this connection is done then Its time to light the charcter with all textures, by using the sIBl lighting I have lighted the character. In maya mental ray type of render it took a lot of time to render because of final gathering and its displacement maps.


• Then I have absorved some problems in texture and told them to our modeler:

Texture in the leg problem with large scales. Decrease the scales to 80% of the size on the present character . Comparitively to the body.Black lines in front legs are more dark decrease the opacity to 75%-80% or change the blend mode. They are apprearing as if they are drawn .Seams are appearing . See that seems dissappear in texture.

Size of scales near hand is large


• After the all the corrections are done the matchmove of all footages is also done and then I have placed the character and set the position of it scaled the camera accoriding to the character size in the scene and then tested the lighting. During this process I have told the matchmove artist to create shapes of the tree and ground, create mesh accordingly to the ground so the animator can do proper animation with proper contactness of the character. We have different shots and different camera angles and adjusted lighting accordingly to it. With the sIBL type of lighting we have made a bit easier in lighting process. After setting all the lights attributes the character looks like this:

Size of scales is modified


• I have abosorved contactness missing in some scenes and then told animator about the problem and then corrected and set the scenes ready ro render with light rig and 8 different passes and container.• After animation of all scenes is done we have imported the geometry cache of the whole character. We got a problem with eyes geometry cache the eyes geometry cache is not imporing, we have asked our faculties about the problem they have told to bindskin the eyes to the character we have also tried that but still we have problem with eyes. • Then we have decided to import directly the animation file of only the eyes and we have over come the problem. • After the animation is done in all scenes and proper placement is done in all scenes with proper lighting the scenes are started with rendering. •The rendering process has taken about 5-7 days for all scenes in 8 passes. • The rendering was done in only 3 to 4 systems with high configuration so I have never placed a problem in rendering exept when its my fault in setting the frame numbers and passes names. Proper naming is done in all scenes with all passes in it.After the rendering process is done I have gone through the compositing part done in fusion and after effects.


• In fusion all images are loaded with loader in different nodes of all passes and color correction is done and blend modes are adjusted accordingly ro the render pass type and finally rendered all scenes in quicktime movie formate in photo-jpeg compression in it and titles animation done in after effects and music is also added according to the scene to sync with the scens and then final render is done in after effects. • I have got a problem in file size the file size is too large and then in quick time player it is exported with movie to apple tv formatte and file size is decresed and finally ou project is done with lots of efforts and many sleepless nights work I have enjoyed a lot and satisfies with the work.


The render passes which I have used for the lighting are shown below :

This is pass In which color information is shown.

The fresnel effect causes images to soften around the edge of the reflective surface.

Color pass

Fresnel pass


Indirect Lighting refers to the feature of processing light reflected from environment surfaces.

Light pass shows the light direction and information of the lights present in the scene.

Indirect pass

Light pass


This pass shows the contactness of the character in background and spread of the shadow.

This show the specular information of the charcter. The character highlights are shown on the character.

Occlusion

Specular pass


This pass shows the shadows of the character on the bg. The light for which shadows are on only gives the shadows.

This pass give the reflecions of the environment on the character.

Shadow pass

Reflectivity pass


The compositing part is completely done in fusion because it is a node based software and for each node we can change the blend mode and color correction can also be done. The setup for the composting is fusion and connection for nodes are shown below :

Connection nodes in fusion


After compositing all scenes in fusion the final rendered image in each scene are:

Shot002 after rendering





In this project I have done match move and roto.I used Pftrack to track the footages the following are the images of two shots.

Match move and Rotoscopy

Shot001 PFTrack

Shot005 PFTrack


• I have enjoyed a lot while doing all match move shots except one shot that is shot005 which irritated me a lot but at last I managed to do that.That was a static shot but we shot it with free hand that is the reason why I faced the problem.It was moving continuously and i was unable to track. At last I have done manual tracking for that shot.

Mesh placed on Shot005


This is the first shot where the character enters .After doing the match move i have built the mesh according to the tree and gave the details like the bumps etc.This is a pan shot .In this the character comes walking from the top.

Mesh palced in Shot002


This is a Focus and Defocus shot and still camera shot. In this the character comes from the top and goes down.In this shot also we built the mesh for character placement.

Mesh placed in Shot003

Mesh placed in Shot006


This is a still shot with no movements and this was easy to track.

This is a human interaction shot in which the 3d character touches the hand of the human and will run away.The other part for me is roto which is a boaring subject for me it took 2 days for me to do that roto.I need to do the roto for the grassWhile shooting the shots also we have faced many problems and we have done shooting two times instead of one time after the second shooting we got exactly what we need and continued with the other parts of our project.

Mesh palced in Shot007


Rotoscopy of grass

Iguana Dissertation

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Transcript of Iguana Dissertation