Marine Mammals
Life history, ecology and conservation
WHO ARE THEY?
Cetacea
whales, dolphins, and porpoises
Carnivora
polar bears, otters, seals, sea lions, walruses
Sirenia
manatees and dugongs
CETACEA: Toothed whales
Bottlenose dolphin
Striped dolphin
Common dolphin
Risso’s dolphin
Focena comune
Globicephalo...
Killer whale
False killer whale
Rough-toothed dolphin
Risso’s dolphin
Harbor porpoise
Pilot whale
Sperm whale...
Cuvier’s beaked whale
...Sperm whale
DNA
CETACEA:
Baleen whales
Fin whale
Right whale
Sei whale
Humpback whale
CARNIVORA:
Pinnipeds
Otariidae
sea lions, fur seals, etc
Phocidae
true seals
Otariidae
ear pinnae
eye
sagittal crest
snout
whiskers
mane
fore flippers
tail
scrotum
hind flippers
hind flippers
tail
whiskers(vibrissae) fore flippers
claws
snouteye
ear
Phocidaeor True seals
CARNIVORA:
Pinnipeds
Odobenidae
walruses
CARNIVORA:
Ursidae
polar bears
CARNIVORA:
Mustelidae
sea otters, weasels, minks, etc
SIRENIA:
Trichechidae
manatees
Dugongidae
dugongs, Stellar’s sea cows
This presentation will focus...
...on dolphins and whales (cetaceans)!
Some terminology....
FROM LAND TO SEA
50 MILLION YEARS AGO 45 MILLION
YEARS AGO
40 MILLION YEARS AGO
35 MILLION YEARS AGO
30 MILLION YEARS AGO
25 MILLION YEARS AGO
20 MILLION YEARS AGO 15 MILLION
YEARS AGO
MESONICHIDAE
PROTOCETIDAEDORYDONTIDAE
SQUALODONTIDAE
DELPHINIDAE
DIVERGENCE
ADAPTATIONS
ADAPTATIONS
Dog
ADAPTATIONS
Underwater life:
• Streamlined body
• Fins
• Head and skull
• Eyes and ears
• Heat conservation
• Salt balance
• Buoyancy
• Genital protrusion, etc
Nostril migration
ADAPTATIONS
• breathing system
ADAPTATIONS
• breathing system
ADAPTATIONS
Perfectly adapted to marine environment!
What are the differences?
DIFFERENCES
DIFFERENCES
baleen
ventral groovestonguejaw
DIFFERENCES
feeding Feeding
Humpback whales
Feeding
Gray whales
Feeding
Gray whales
Feeding
Other whales
Teeth
DIFFERENCES
Teeth
DIFFERENCES
HOW DO YOU DETERMINE THE AGE OFHOW DO YOU DETERMINE THE AGE OFA DOLPHIN AND A WHALE?A DOLPHIN AND A WHALE?
Feeding
Group waiting to feed
Sentinel
Dolphins feeding
Sentinel
Feeding
Bottlenose dolphin
Feeding
Common dolphin
Feeding
Killer whale
Feeding
Sperm whale
Feeding
OTHER CAPTURE TECHNIQUES:
“crater feeding”
“fish whacking”
“strand feeding”
How dolphins find their prey?
How echolocation works?
Returning echo
Sound emission
Where is the food?
Migration...
... and residency
How dolphins move
Great variety of cetaceans
Tongue =
Heart =
Blue whale
Group sizes
Small schools
Large schools
Single/Pairs
Groups
• Advantages
• Disadvantages
Schools, pods & herds
SOCIAL BEHAVIOR
Fission-fusion societies
Complex societies
Alliances and Superalliances
Courtship & Mating
Not easily distinguishable....
female
male
navel anusgenital slit
mammary slit
Birth
Long term bonds
Cetaceans’ sensory world
• Sight
• Smell
• Taste
• Touch
• Sound
Cetaceans’ sensory world
SOUND
• Communication whistles
• Echolocation clicks
Song of a whale
Dolphin whistles
Cetaceans’ sensory world
Modern humans=7.06Great apes=1.91Odontocetes=3.78Odontocetes=3.78
Brain and intelligence
Social learning
“Culture”
Self-recognition
Sponge carrying
Unique mammals
As humans increase their exploitation of marine As humans increase their exploitation of marine resources, individual dolphins, porpoises resources, individual dolphins, porpoises and whales suffer, their societies and whales suffer, their societies are disrupted, and their populations declineare disrupted, and their populations decline
(Whitehead et al. 2000)
Worldwide threats to cetaceans
WHAT ARE THE MOST IMPORTANT WHAT ARE THE MOST IMPORTANT ANTHROPOGENIC THREATS TO MARINE ANTHROPOGENIC THREATS TO MARINE MAMMALS?MAMMALS?
Present exploitation
• Aboriginal hunts
• Hunts in or by developing countries
• Whaling for scientific purpose
• Live capture
By-catch
“It refers to the incidental capture of non-target species in fisheries” (Whitehead et al. 1999)
Effects nearly every cetacean species
By-catch
Often unsustainable
Primary cause of population decline
May bring species close to extinction
560 <200
Habitat loss and degradation
Serious threat to inshore, freshwater species
Pollution
Oceans as
infinite trash
dumps...!?!
Competition with fisheries
likely to be a threat
BUT...
conclusive evidence is lacking due to complex ecosystem dynamics
Humans: use sounds in same wide range of frequencies to explore oceans
Noise is incidentally produced by most marine activities
Humans have potential to interfere acoustically with the lives Humans have potential to interfere acoustically with the lives of cetaceansof cetaceans
Noise and disturbance
Collisions with ships
Significant impact on mid/large cetaceans in areas of high/fast ship traffic
Global climate changes
“It’s generally agreed that the Earth’s climate is changing systematically in response to human activities” (Intergovernmental Panel on Climate Change 1995)
“These changes are likely to affect virtually all life, including cetaceans” (IWC 1997)
Thank you!
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