The lower jaws of lizards, birds, fish and even dinosaurs are comprised of multiple bones per side. Yet mammals diverged from all other vertebrates and settled on just one bone, repurposing the extra ...

A Erin Flynn, conservation education curator at Henry Vilas Zoo in Madison, Wis.: Mammals such as giraffes, bears, humans and many more are vertebrate animals, meaning they have spines. They’re also ...

Vertebrates are animals that have a spine (backbone) inside their body. Other organisms, like spiders and snails, that don’t have a backbone are called invertebrates. Fran: Here at the farm there are ...

A tiny fossil skull found within 195-million-year-old Chinese sediments provides evidence that crucial features of mammal anatomy evolved more than 45 million years earlier than previously recognized.