A grey squirrel sitting on a log holding an acorn in its two paws. Thumbnails likely played a key role in rodents’ evolutionary success. Instead of sharp, pointy claws, several rodent species ...

Rodents may have a rule of thumbnails. Many rodents have curved claws that help the animals climb or dig. But most also have flat nails on their thumbs, researchers report in the Sept. 4 Science. This ...

Many rodents have nails on their thumbs and claws on the rest of their fingers. A new study suggests this trait might have been key to their world domination. Missagia et al. Rodents are the largest ...

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 ...