Sloths weren't always slow-moving, furry tree-dwellers. Their prehistoric ancestors were huge — up to 4 tons (3.6 metric tons) — and when startled, they brandished immense claws.

Prehistoric fossils dating back to the Ice Age discovered in South Louisiana. What prehistoric animals used to roam Louisiana ...

Remains of giant sloths and proto-elephants were found interspersed with burnt human bones and ceramics in Mexico's Sac Actun cave system.

For example, water levels rose more than 300 feet at the end of the Ice Age, flooding the cave system and preserving the remains of extinct megafauna. Humans likely didn't live in the caves, but ...

Bolg amondol was a raccoon-sized armored mostesaurian lizard that lived about 77 million years ago, similar to today’s Gila monsters ( Heloderma horridum ). It is named after the goblin prince from ...

In this video, we dive into the details of this frozen discovery and explore other incredible prehistoric finds that reveal the mysterious lifeforms that once ruled our planet.

Reference: “The emergence and demise of giant sloths” by Alberto Boscaini, Daniel M. Casali, Néstor Toledo, Juan L. Cantalapiedra, M. Susana Bargo, Gerardo De Iuliis, Timothy J. Gaudin, Max C. Langer, ...

One of the cassowary's most prehistoric-looking features is its feet. Each foot has three toes, with the inner toe bearing a dagger-like claw that can grow up to 5 inches (12 centimeters) long.

Ancient sloths lived in trees, mountains, deserts, boreal forests, and open savannas. These habitat differences mainly explain the wide variation in size among sloth species. Illustration by Diego ...

Discover the stunning 12,500-year-old rock art of Colombia's Amazon rainforest in our latest video, "12,500-Year-Old Rock Art: A Glimpse into Prehistoric Amazon." This ancient artwork reveals a ...

Megatherium, the giant ground sloth, was an herbivore of massive proportions. This colossal mammal, native to the woodlands and savannas of prehistoric America, grew up to 20 feet long. Despite its ...