Identifying human versus non-human Identifying human versus non-human skeletal remains in the fieldskeletal remains in the field

Amy E. KellyAmy E. KellyForensic InvestigatorForensic Investigator

Coconino County Medical Examiner’s Coconino County Medical Examiner’s OfficeOffice

Human vs. Non-humanHuman vs. Non-human

In modern forensic cases, 25-30% of the In modern forensic cases, 25-30% of the presented cases are non-human in origin.presented cases are non-human in origin.

Access to and using a comprehensive Access to and using a comprehensive comparative collection is necessary.comparative collection is necessary.

Using a variety of literature in the field is Using a variety of literature in the field is helpful and an easy and efficient means to helpful and an easy and efficient means to improve animal vs. human identification improve animal vs. human identification (Cruz-Uribe and Klein 1994, Gilbert 1990, (Cruz-Uribe and Klein 1994, Gilbert 1990, Ubelaker 1989).Ubelaker 1989).

If in any doubt, GPS, photograph and describe If in any doubt, GPS, photograph and describe the specimen and “scene” before moving or the specimen and “scene” before moving or collecting the remains and bringing it to the collecting the remains and bringing it to the CCME office for analysis. If appropriate, call CCME office for analysis. If appropriate, call me or the CCME investigator on-call.me or the CCME investigator on-call.

Human vs. Non-humanHuman vs. Non-human

The first question that should be asked is “Is it The first question that should be asked is “Is it bone?” and not wood, shell or plastic or rock.bone?” and not wood, shell or plastic or rock.

If yes, is it cranial or post-cranial? (cranial bones are If yes, is it cranial or post-cranial? (cranial bones are usually thin, flat or even irregular in structure; look usually thin, flat or even irregular in structure; look for sinuses, sutures or sockets)for sinuses, sutures or sockets)

Post-cranial bones are typically long, skinny and can Post-cranial bones are typically long, skinny and can be flat. Exceptions are the bones of the hands and be flat. Exceptions are the bones of the hands and feet, vertebrae and the pelves.feet, vertebrae and the pelves.

Then, look to see if the bone is whole or fragmented.Then, look to see if the bone is whole or fragmented. Also, are the bones adult in age or juvenile? (Fused or Also, are the bones adult in age or juvenile? (Fused or

unfused epiphyses)unfused epiphyses) And lastly but most importantly, could this be And lastly but most importantly, could this be

human?human?

Human vs. Non-humanHuman vs. Non-human

Most mammalian bones share similar Most mammalian bones share similar morphological features between species. The morphological features between species. The exceptions are marine mammals and some exceptions are marine mammals and some unusual critters like tree sloths.unusual critters like tree sloths.

The primary difference is size. However some The primary difference is size. However some animals, such as deer, have bones that are very animals, such as deer, have bones that are very close in size to an adult human.close in size to an adult human.

Other mammals that cause confusion are bear Other mammals that cause confusion are bear and raccoon for their paws (Klepinger 2006). Bear and raccoon for their paws (Klepinger 2006). Bear paws look similar to adult hands and raccoon paws look similar to adult hands and raccoon paws are easily confused for children’s hands.paws are easily confused for children’s hands.

Human vs. Non-humanHuman vs. Non-human

Which hand is human versus bear?Which hand is human versus bear?

Human vs. Non-humanHuman vs. Non-human

Human versus raccoonHuman versus raccoon

Human vs. Non-humanHuman vs. Non-human

Easy identificationsEasy identifications

Human vs. Non-humanHuman vs. Non-human

But what if you come across bones like these?But what if you come across bones like these?

Human vs. Non-humanHuman vs. Non-human

Humans: bipedalHumans: bipedal Pelvis is broad and shallow (bowl-shaped)Pelvis is broad and shallow (bowl-shaped) The femur is the longest bone in the body with a single linea The femur is the longest bone in the body with a single linea

asperaaspera The tibia and fibula are separate bones and the tibia is triangular The tibia and fibula are separate bones and the tibia is triangular

in cross-section with a small tibial tuberosityin cross-section with a small tibial tuberosity Long and narrow foot with multiple bones for bipedialityLong and narrow foot with multiple bones for bipediality

Other mammals: Quadrupedal (mostly)Other mammals: Quadrupedal (mostly) Pelvis is long and narrow Pelvis is long and narrow The femur is short relative to the body size. If the femur’s length The femur is short relative to the body size. If the femur’s length

is comparable to an adult human femur, the diameter may be is comparable to an adult human femur, the diameter may be twice as thick as a human femur (i.e., cow) with a double or twice as thick as a human femur (i.e., cow) with a double or plateau linea asperaplateau linea aspera

The tibia and fibula are often fused and the tibia is more rounded The tibia and fibula are often fused and the tibia is more rounded in cross-section with a large tibial tuberosity or longitudinal ridge.in cross-section with a large tibial tuberosity or longitudinal ridge.

Legs of larger mammals are modified toes and fingers for speed Legs of larger mammals are modified toes and fingers for speed and agility and agility

Human vs. Non-humanHuman vs. Non-human

Humans:Humans: Large, broad and flat vertebral bodyLarge, broad and flat vertebral body Short spinous process (2-3 inches at the most)Short spinous process (2-3 inches at the most) Sacrum is triangular in shape and composed of 5 fused Sacrum is triangular in shape and composed of 5 fused

vertebrae, which are broad compared to length and vertebrae, which are broad compared to length and flattened anteriorly-posteriorlyflattened anteriorly-posteriorly

Other mammals: Other mammals: Small vertebral body, often convex on one side and Small vertebral body, often convex on one side and

concave on the otherconcave on the other Long spinous process (>6 inches in some larger Long spinous process (>6 inches in some larger

mammals)mammals) Sacrum is long and narrow with fewer fused vertebrae Sacrum is long and narrow with fewer fused vertebrae

(3-4)(3-4)

Vertebrae

Human vs. Non-humanHuman vs. Non-human

Humans:Humans: Designed for rotation (i.e., throwing, swinging)Designed for rotation (i.e., throwing, swinging) Long axis of scapula is perpendicular to scapular spine, which is why Long axis of scapula is perpendicular to scapular spine, which is why

it’s triangular shapedit’s triangular shaped Clavicle presentClavicle present Humerus, radius and ulna are not weight bearing so they are not Humerus, radius and ulna are not weight bearing so they are not

robust. Ulna and radius not fusedrobust. Ulna and radius not fused Large thumbLarge thumb

Other mammals:Other mammals: Designed for front-back strideDesigned for front-back stride Long axis of scapula is parallel to scapular spine, which is why it’s Long axis of scapula is parallel to scapular spine, which is why it’s

rectangular shapedrectangular shaped Clavicle absent in most non-human mammalsClavicle absent in most non-human mammals Humerus, radius and ulna are weight bearing and robust. Ulna and Humerus, radius and ulna are weight bearing and robust. Ulna and

radius are often fused to support these weight bearing limbsradius are often fused to support these weight bearing limbs Small thumb, even on mammals with similar hands (bear and Small thumb, even on mammals with similar hands (bear and

raccoon)raccoon)

Forelimbs

Human vs. Non-humanHuman vs. Non-human

Juvenile RemainsJuvenile Remains The most common human bones to be mistaken for The most common human bones to be mistaken for

animal bones are bones from infants.animal bones are bones from infants. The ends of the long bones, bones of the hands and The ends of the long bones, bones of the hands and

feet and clavicle are not fusedfeet and clavicle are not fused These unfused bones have indistinct edgesThese unfused bones have indistinct edges Multiple ossification centers and unfused epiphyses Multiple ossification centers and unfused epiphyses

increase the number of bones in infants and childrenincrease the number of bones in infants and children Epiphyses (the ends of long bones) when separated Epiphyses (the ends of long bones) when separated

from the rest of the skeleton do not look human to from the rest of the skeleton do not look human to the untrained eyethe untrained eye

Long bones are thinner in cross-sectionLong bones are thinner in cross-section Cranial bones can separate and lack the diploe Cranial bones can separate and lack the diploe

structure, are uniform in thickness and can be structure, are uniform in thickness and can be confused with tortoise carapace. Petrous portion is confused with tortoise carapace. Petrous portion is separate in infants and due to it’s dense nature, separate in infants and due to it’s dense nature, often survives burial better often survives burial better

Can be confused with smaller mammals such as Can be confused with smaller mammals such as raccoon, rabbit or even birdraccoon, rabbit or even bird

Human vs. Non-humanHuman vs. Non-human

Human vs. Non-humanHuman vs. Non-human

Mandibles from infantsMandibles from infants

Petrous bones circled

Human vs. Non-humanHuman vs. Non-human

Human infant and fetal bones, recovered from a burialHuman infant and fetal bones, recovered from a burial

Human vs. Non-humanHuman vs. Non-human

Fragmented and burned remains are more Fragmented and burned remains are more challenging to correctly identify than intact challenging to correctly identify than intact remains for distinguishing between human and remains for distinguishing between human and non-human remainsnon-human remains Ids can be done macroscopically by morphologyIds can be done macroscopically by morphology**** Ids can be done microscopically (histological Ids can be done microscopically (histological

examination)examination)

****For our purpose, we only need to discuss For our purpose, we only need to discuss macroscopic analysismacroscopic analysis

Human vs. Non-humanHuman vs. Non-human

Skull Fragments?Skull Fragments?

Human vs. Non-humanHuman vs. Non-human

Fragmentary and burnt bison bones.Fragmentary and burnt bison bones.

Human vs. Non-humanHuman vs. Non-human

Traumatized and burned pig bones

Human vs. Non-humanHuman vs. Non-human

Macroscopic characteristics: cortical bone much thicker in animal long bones than in human; humeral and femoral cortical thickness in humans is about ¼ of total diameter

Bone macroscopic characteristics: cranial bone diploe relative to cranial cortical (tabular) bone is thinner in animals compared to humans

Human vs. Non-humanHuman vs. Non-human

Review:Review: Ask first, “Is it bone?”Ask first, “Is it bone?” Ask second, “Could it be human Ask second, “Could it be human

and why?” (i.e., context, and why?” (i.e., context, size/shape of bones, do the size/shape of bones, do the bones fit bipedal locomotion?)bones fit bipedal locomotion?)

Have some reference material to Have some reference material to aide in more accurate aide in more accurate assessment of human versus assessment of human versus animal (I can provide animal (I can provide photocopies)photocopies)

If in doubt, If in doubt, no matter how muchno matter how much, , GPS, photograph and document GPS, photograph and document the remains, then collect or call the remains, then collect or call me or the on-call investigatorme or the on-call investigator

Human vs. Non-humanHuman vs. Non-human

Call me directly if you ever come upon this…

Thanks to the following:Thanks to the following:

Staff at CCME for support while I write lectures and play Staff at CCME for support while I write lectures and play with bones.with bones.

CCSO CI and SAR for all your hard work and selfless CCSO CI and SAR for all your hard work and selfless dedication to helping victims and their families with the dedication to helping victims and their families with the multitude of hours and energy invested to ensure multitude of hours and energy invested to ensure recovery.recovery.

My dear friends and boyfriend who watch my child so I My dear friends and boyfriend who watch my child so I can present these lectures.can present these lectures.

Human vs. Non-humanHuman vs. Non-human

For JoeFor Joe