An online exhibit for the Harvard Museums of Science and Culture

Sharks are some of the oldest and, from an evolutionary perspective, some of the most successful marine vertebrates ever to have lived. They have been around in their current form for over 400 million years, since the geologic period known as the Devonian, and their earliest ancestors emerged in the Silurian, some 50 million years before that. Sharks have spent their entire evolutionary history in the aquatic environment, and the body design in many species has been honed over hundreds of millions of years to increase swimming performance. Attributes of body form, fins and even the skin, work in concert, enabling sharks to slice through water and execute complex maneuvers with startling speed and precision.