Functional Morphology

The way bones grow depends on how they are used. For example, long and thin foot bones are indicative of an animal that spends a lot of time running (deer, horse, etc.). Zooarchaeologists can, therefore, look at the different shapes of a bone to identify what animal it belongs to, often to the species level.

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What kind of animal is it?

The three most common types of animal bones you are likely to find are:

• Mammal Bones

• Bird Bones

• Fish Bones

Commonly found mammal species include rabbits (Lagamorph), squirrels (Rodentia), raccoons (Carnivora), and deer (Artiodactyla).

The bones of large mammals (deer, horses,etc.) are probably the easiest to identify due to their size. The bones of small mammals (mice, squirrels,etc.) are more difficult to identify due to their similarity to bird bones. However, all mammal bones have some easy to identify common characteristics.

• Spongy (Cancellous) bone: Spongy bones resembles a sponge in that it has many air spaces within it. This type of bone is very commonly seen on the inside and ends of mammal long bones.

• Thick cortex: Most mammal bones are similar to bird bones in that they are both hollow inside. The difference between the two is that mammal bones have a thick outer wall (relative to the size of the bone) as opposed to bird bone which has a thin outer wall.

For more information on the mammalian skeleton or identifying mammal bones see these pages.

Perhaps the most easily found bird bones are those that belong to the chicken and turkey. After your next poultry dinner, try scraping all the remaining skin and flesh off your meal and you will have a great opportunity to learn more about bird bones.

Bird bones are easy to identify based on their:

• Angular edges: The bones of birds tend to be more square and triangular than rounded like mammal bones are.

• Thin cortex: Bird bones, like mammal bones, are hollow inside. The difference between the two is that mammal bones have a thick outer wall (relative to the size of the bone) as opposed to bird bone which has a thin outer wall.

• Supporting webs: To compensate for the thinner walls in bird bones, the inside of a hollow bird bone contains thin supporting webs that look like spider webs. These webs help the bone resist breaking but keep the bones light enough so that the bird can fly.

For more information on the bird skeleton or identifying bird bones see these pages.

Fish Bones:

Fish bones are not often found outdoors except on the banks of rivers. You can, however, examine the bones from your next fish dinner.

Fish bones are easy to identify based on their:

• Woody internal texture: If you break open a fish bone, the inside is not hollow like a bird or mammal bone but instead resembles a broken twig.

• Thinness: Fish bones are usually so thin that they can be described as flat. This thinness causes many fish bones to be translucent (allow light to pass through).

For more information on the fish skeleton or identifying fish bones see these pages.