Cephalopods were among the first predatory animals to hunt in the ancient seas. They evolved more than 500 million years ago—long before fish got going—from a small animal with a shell like a ...

The many chambers of their shells likely helped these cephalopods glide through the planet’s warm, shallow seas. A thin, tubelike structure called a siphuncle pumped air through the interior ...

Ammonites were shelled cephalopods that died out about 66 million years ago. Fossils of them are found all around the world, sometimes in very large concentrations. The often tightly wound shells of ...

The chambered, or pearly, nautilus (Nautilus pompilius) is a charismatic cephalopod species known for its exceptional spiraling, chambered shell. It belongs to a family that has barely changed since ...

If there was a prize for the world’s strangest cephalopods, we’re pretty sure argonauts would win. Need convincing? Well, first they make a weird ‘shell’ that isn’t technically a shell. Second, they ...