Identifying Human Remains: Human or Non-human

Human vs. Non-human In modern forensic cases, 25-30% of the presented cases are non-human in origin. Access to and using a comprehensive comparative collection is necessary. If in any doubt, photograph and describe the specimen and “scene” before moving or collecting the remains and bringing it to the Lab for analysis.

The first question that should be asked is “Is it bone?” If yes, is it cranial or post-cranial? (cranial bones are usually thin, flat or even irregular in structure; look for sinuses, sutures or sockets) Post-cranial bones are typically long, skinny and can be flat. Exceptions are the bones of the hands and feet, vertebrae and the pelves.

Then, look to see if the bone is whole or fragmented. Also, are the bones adult in age or juvenile? (Fused or unfused epiphyses) And lastly but most importantly, could this be human?

Most mammalian bones share similar morphological features between species. The primary difference is size. However some animals, such as deer, have bones that are very close in size to an adult human. Other mammals that cause confusion are bear and raccoon for their paws.Bear paws look similar to adult hands and raccoon paws are easily confused for children’s hands.

Which hand is human versus bear?

Human versus raccoon

Easy identifications

But what if you come across bones like these?

Humans: Bipedal Pelvis is broad and shallow (bowl-shaped) The femur is the longest bone in the body The tibia and fibula are separate bones and the tibia is triangular in cross-section Legs of larger mammals are modified toes and fingers for speed and agility

Other Mammals: Quadrupedal (mostly) Pelvis is long and narrow 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 twice as thick as a human femur (i.e., cow). The tibia and fibula are often fused and the tibia is more rounded in cross-section.

Humans: Vertebrae Large, broad and flat vertebral body Sacrum is triangular in shape and composed of 5 fused vertebrae, which are broad compared to length and flattened anteriorly-posteriorly.

Other Mammals: Small vertebral body, often convex on one side and concave on the other Sacrum is long and narrow with fewer fused vertebrae (3-4)

Humans: Forelimbs Designed for rotation Long axis of scapula is perpendicular to scapular spine Clavicle present Humerus, radius and ulna are not weight bearing so they are not robust. Ulna and radius not fused Large thumb Small thumb, even on mammals with similar hands (bear and raccoon)

Other Mammals: Designed for front-back stride Long axis of scapula is parallel to scapular spine, which is why it’s rectangular shaped Clavicle absent in most non-human mammals Humerus, radius and ulna are weight bearing and robust. Ulna and radius are often fused to support these weight bearing limbs

Human vs. Non-human

Human vs. Non-human Mandibles from infants Petrous bones circled

Human vs. Non-human Human infant and fetal bones, recovered from a burial

Human vs. Non-human Fragmented and burned remains are more challenging to correctly identify than intact remains for distinguishing between human and non-human remains Ids can be done macroscopically by morphology** Ids can be done microscopically (histological examination)

Human vs. Non-human Skull Fragments?

Human vs. Non-human Fragmentary and burnt bison bones.

Traumatized and burned pig bones Human vs. Non-human Traumatized and burned pig bones

Human vs. Non-human