Humans and other mammals share the same distant ancestors, so our bones are almost identical to theirs in form and function. The bones in your hand have the same layout as those in bat wings and in the fins of whales, for instance.
What differs most between species, however, is the thickness, size and density of minerals that provide strength to bones. This is what scientists are most interested in when trying to determine the origin of mysterious bones.
Even today, mistaken identifications of human bones from animal remains can occur. To the untrained eye, the bones within the paw of a bear, for instance, look very similar to the bones within the human hand.
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