The data suggest that all modern rodents descend from a common ancestor that had thumbnails too. This early rodent ancestor's thumbnails may help explain how rodents took over the world. The ...

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 ...

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 ...

Researchers (left to right) Gordon Shepherd, Anderson Feijó, Lauren Johnson, and Rafaela Missagia, working in the Field Museum’s mammal collections. Picture a squirrel eating an acorn. It’s holding ...