A new study suggests their evolution helped us develop our social skills.

PALEONTOLOGY
<em>Kumimanu biceae</em> would have dwarfed the penguins of today.
Paleoart: Visions of the Prehistoric Past explores the first 160 years of illustrating extinct species.
The name Borealopelta markmitchelli honors the man who spent more than five years revealing, bit by bit, the amazing creature encased in stone.
"I just knew it was not something that you usually find."
The skeleton is suspended from the main entrance hall's ceilings, providing visitors with a 360-degree view of the largest animal ever known to have lived on Earth.
In the 24 years since the original 'Jurassic Park' was released, what we know about dinosaurs has changed a lot. Here's some of the new research that may change how you imagine these ancient animals.
These 200-ton ocean dwellers had a growth spurt 3 million years ago.
The as-yet-unnamed nodosaur was so well preserved that it “might have been walking around a couple of weeks ago.”
There is no ankylosaurus, only Zuul.
See who your neighbors would have been 100 million years ago.
The next time you’re feeling less than brave, remind yourself you’re already one of nature’s great success stories.
Paleontologists say a prehistoric marsupial called "Didelphodon vorax" had the strongest bite force of any mammal that’s ever lived.
The animal lived off the coast of what is now Washington state about 10 million years ago and probably fished like seals do, relying on the power of its oversized eyes to track its prey.
The American Museum of Natural History is highlighting its artifacts in a whole new way.
Two specimens of the Chihuahua-sized animals have just rearranged the branches of the carnivore family tree.