2 October 2024

The diagram above, from Arizona State University’s Ask A Biologist, shows that beneath our skin humans, birds and bats all have the same bones in our arms/wings but the bones have evolved to match our lifestyles.

We humans use our arms to reach and our hands to grab and manipulate. Birds and bats use their “arms” for flying. You can see it in our bones.

Each bone has changed compared to humans.

Big changes start at the wrist with huge changes in the “hands” and fingers.

Birds have only two “fingers” and their “thumbs” (the alula) are used only for slow flight maneuvers.

See more in the original article at Ask A Biologist: Human, Bird, and Bat Bone Comparison

(diagram from asu.edu Ask A Biologist coloring pages for kids, CC BY-SA)