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Human, bird, and bat bone comparison

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  • Common ancestor: a single species that gave rise to at least two other species.

Human, bird, and bat bone comparison

From the outside human arms, bird wings, and bats wings look very different. Humans are covered in skin, birds are covered in feathers, and bats are covered in hair. But on the inside there are many similarities among human, bird, and bat forearms. Did you know that humans, birds, and bats have the exact same types of bones in their forearm? These organisms share the same forearm bones because they all evolved from a common ancestor.

Human, bird, and bat forearm bones include the humerus, ulna, radius, carpals, metacarpals, and phalanges. Can you identify these bones on the diagram below?

bone comparison illustration

While these organisms all have the same basic types of bones, the bones have been modified to have different functions. Humans use their forearms to reach and pick up objects, swing a baseball bat, and play the piano. Bird and bat forearms have evolved into wings allowing them to fly. Can you find any more differences and similarities among human, bird, and bat forearms?

Download your own human, bird and bat bone coloring page.

Looking inside bones

Bones of animals are strong and mostly dense, but some animal bones are different. Unlike human bones, birds have a lot more empty space inside their bones. This makes them lighter so they can fly. Bird bones also lack the dense center section of bone marrow, which also reduces their weight.

Bird and Human Bone Comparison



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