For almost two decades, scientists have debated whether sponges or comb jellies are the first animal lineage. Now some are ...

The next time you go wild swimming, whether in a lake, river or sea, you are probably sharing the water with one of your tiniest, yet closest relatives. Subscribe to our newsletter for the latest ...

Earth’s first sponges may have been ghostly, soft-bodied pioneers—ancient animals that evolved long before their skeletons ever appeared in stone.

Animals, from worms and sponges to jellyfish and whales, contain anywhere from a few thousand to tens of trillions of nearly genetically identical cells. Depending on the organism, these cells arrange ...

At first glance, this mammal looks like a horse gone terribly wrong. But, in reality, Chalicotherium is far from a botched ...

Such evidence suggests early heartworms evolved alongside canines millions of years ago. Mosquitoes existed long before ...