Explore 25 giant prehistoric ancestors of modern day animals! See colossal creatures like elephant-sized sloths and rhinos.

New footage from a Japanese fishing vessel captures a live giant squid at the ocean's surface, an encounter so unusual that scientists only confirmed the species in its natural habitat in 2004.

The ocean is home to animals so enormous that some can outweigh entire groups ...

The enormous and slow-moving creatures are being pushed closer and closer to dangerous roadways. Here's how conservationists are thinking creatively to keep them safe.

The spiniest plant communities in the tropics grow where large browsing mammals once fed. In much of the Americas, many of those animals vanished thousands of years ...

Our understanding of animal behavior depends on observation. Researchers can study how animals are born, grow and develop. We can gather evidence of how they interact with each other and their ...

Ancient sloths lived in trees, on mountains, in deserts, in boreal forests and on open savannas. Some grew as large as elephants. Illustration by Diego Barletta The largest sloth of all time was the ...

Giant panda cub Xiao Qi Ji experiences snow for the first time just beyond his indoor exhibit on Sunday. Though he did not venture further, his parents Mei Xiang and Tian Tian played around outside.

Today, the vast plains of the Americas often evoke images of agriculture or modern development. We picture massive fields of wheat blowing gently in the wind, long highways stretching into the horizon ...

The word "dinosaur" tends to evoke giant animals with massive bodies, long necks and tails, and tiny heads. These "quintessential dinosaurs" actually represent one prominent subgroup of the Dinosauria ...