How to Determine an Animal Carcass by the Bones

How to Determine an Animal Carcass by the BonesA pile of bones encountered in the woods is a mystery, a puzzle that begs to be solved. Bones may bear little resemblance to the animal that once possessed them. They may have the appearance of a bizarre, alien creature or undiscovered life form, but many bones can be fairly easily traced back to the animal that owned them using clues from what little is left behind. The more of the skeleton available, the more features you have to study and the better your chances of making a positive identification.


Difficulty: Moderately Challenging

The Area

Step 1
Think about companion animals first. Because they dominate in number and tend to wander almost all areas used by humans, the most common animals, such as cats and dogs, should be considered and eliminated first.
Step 2
Consider wild animals common to the area where the bones were found. While you may encounter an escaped exotic animal skeleton or the remains of an animal that wandered out of its usual zone of habitation, any bones you find are far more likely to belong to a local animal.
Step 3
Keep unusual animal possibilities in mind. Do not entirely eliminate somewhat unlikely animals because people keep a variety of legal and illegal imported and domestic animals as pets. Occasionally, people set these animals free.
Step 4
Consult professional wildlife resources. Your state Department of Natural Resources or local university usually can assist in identification or direct you to a community resource able to help you in your quest.

The Bones

Step 1
Pinpoint the animal's identity through the presence of unique horns, antlers or tusks. Features found in a single type of animal or animal bone also may help narrow your choices. For example, a reptile skull has two temporal fossae (holes located behind each of the eye sockets), while mammals have only one.
Step 2
Look to the teeth. Knowing what your mystery animal ate is key to a positive identification. Insectivores have sharp-pointed molars. The molars of omnivores are flat, and their canine teeth are smaller.

Carnivores have teeth somewhat like our own; their incisors help penetrate and keep a grip on food, molars crush and grind food, but their canine teeth are much larger, wider or longer. These teeth can be used to attack prey or for self-defense.

Tooth formations can vary among subfamilies and subspecies. For example, each type of bear may have a slightly different diet, requiring smaller, larger or flatter molars and greater or lesser canines.
Step 3
Judge the relative size and thickness of the bones. The length and girth of leg bones can tell you whether the animal supported a heavier body, like that of a mature cow, or if it was large but lighter weight, like a deer.
Step 4
Double-check that the bones are animal bones. Mammal bones are rounded and may have a spongy cavity inside, or they may have a thick outer layer with a hollow core; only mammal bones, however, have that spongy cavity.

Rodents and smaller animals have bones that may be mistaken for bird bones at first glance. Bird bones have thin walls, a more angular appearance and internal features with the appearance of spider webs. Even the largest species of birds have very short femur (leg) bones.

Fish bones are nearly flat and have an internal texture like wood. They are more likely found around a water source, but prey animals can carry them to other locations.

Article Written By Alice Moon

Alice Moon is a freelance writer with more than 10 years of experience. She was chosen as a Smithsonian Institute intern, working for the National Zoo in Washington, D.C., and has traveled throughout Asia. Moon holds a Bachelor of Science in political science from Ball State University.

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