With terrifyingly sharp teeth arranged around a circular mouth, lampreys look about as primitive a vertebrate as you could imagine. But a new study finds that the animals have a surprising similarity ...

Sea urchins look like an inanimate bundle of needles, but a closer look at these alien-like creatures reveals a surprisingly ...

Primitive animals called comb jellies can fuse their bodies and nervous systems together. Comb jellies split from the ancestors of all other living animals about 700 million years ago and have ...

Brains are like sponges, slurping up new information. But sponges may also be a little bit like brains. Sponges, which are humans’ very distant evolutionary relatives, don’t have nervous systems. But ...

Strange sea creatures called ctenophores have a fused nerve net where scientists expected to see synapses. Did they evolve their nervous system separately from other animals? When you purchase through ...

All bilateral creatures have some asymmetry, such as the human heart being located slightly to the left and the liver being ...