The humble rodent “thumb” may not seem like an obvious window into evolution, but its keratinized tip – the unguis (hoof, claw, or nail) – turns out to reveal striking insights into rodent history and ...

Meet the evolutionary hipster that beat Portland to weirdness by 30 million years. We’ve just found North America’s oldest beaver fossils. They’re rewriting everything we thought about these ...

The legions of squirrels breaking into backyard bird feeders benefit from a surprising trait developed over millions of years—tiny hands with four claws and a human-looking thumbnail. This combination ...

The arrangement of the bones that form the joint (the articulation) between the lower jaw and the skull is a key hallmark of vertebrates. Their configuration has long been used to draw a line in the ...