Fossilized footprints and tracks dating back 50 million years ago discovered at the John Day ... This marked "one of the few known reptile trackways from this time period in North America ...

Fossil evidence has established that modern dolphins and whales derived from small, four-limbed, hoofed animals that lived in South Asia during the Eocene around 50 million years ago.

Miopetaurista specimens have previously been unearthed from the Miocene and Pliocene (23.03–5.33 million and 5.33–2.58 million years ago, respectively) epochs of China, France and Germany.

Ancient horses lived in North America from about 50 million to 11,000 years ago, when they went extinct at the end of the last ice age, said Ross MacPhee, curator emeritus of mammalogy at the ...

North America was home to around 40 to 50 species of rhinos at one time or another, says Richard Hulbert, a vertebrate paleontologist at the Florida Museum of Natural History. But the last of these ...

Next the butterflies crossed the Bering Land Bridge — a land bridge that once existed between Russia and North America — and reached what is now Russia 75-60 million years ago. .

Tyrannosaurus rex ancestors would have moved from Asia to North America around 70 million years ago, researchers say. Pedro Salas/Sergey Krasovskiy Sign up for CNN’s Wonder Theory science ...

Tyrannosaurus rex ancestors would have moved from Asia to North America around 70 million years ago, researchers say. Pedro Salas/Sergey Krasovskiy Sign up for CNN’s Wonder Theory science ...

Butterflies first fluttered onto the scene in North America about 100 million years ago, according to a genetic analysis. The findings have been used to generate a detailed butterfly family tree ...

Butterflies likely split from nocturnal moths around 100 million years ago in present-day western North America or Central America, a new study of the winged insects finds.