Ammonites are extinct marine animals that were once a ubiquitous life form in the oceans about 400 millions years ago. Ammonites probably fed on smaller forms of sea life and, in turn, were food for larger fishes and reptiles that hunted in the ancient seas,
A mass die-off occurred about 65 million years ago at the end of the Cretaceous Period. The name means “horns of Ammon" (the Egyptian horn- bearing God). Ammonites are a distant cousin of the modern Nautilus.