Great White Shark (Carcharodon carcharias)
In North America, the Great White Shark is primarily found off the coasts of California and the northeast, but they live throughout temperate and tropical oceans and can occur along the length of both coasts. While they can reach 21 ft (6.5 m) long, they actually average a more modest 13-17 ft (4-5 m) when mature.
Great Whites are relatively intelligent and can be fairly social. In South Africa where most Great White research is done, they have been shown to organize into clans like wolf packs, where each individual has a clear rank under an alpha leader. They are typically not violent in their social interactions with other Great Whites - they rely on rituals and displays to establish dominance. Interestingly, females are dominant over males in such situations.
They are ambush predators whose diet is composed of large vertebrates such as seals, dolphins or big fish like tuna. Most prey is taken by surprise from behind or below, typically in the early morning hours when visibility is poorer. Great Whites generally focus on species with higher fat content - humans are too bony to be considered appealing, but since swimmers or surfers can resemble some of their preferred prey (seals) attacks occasionally happen.
photo by Tom Clifton on Flickr
(via: Peterson Field Guides)