On rare occasions, active sharks will cooperate in a hunt. Researchers have observed this phenomenon primarily in sevengill sharks . The sharks form a wide ring around a single seal, and slowly move in. When they get close enough, one shark will suddenly attack, and the rest will follow. This sort of behavior sometimes occurs in other shark species, but it is extremely rare.
Scientists also know that migration plays a big part in the lives of most shark species.
The main reason most sharks migrate is that their food migrates. Different marine animals gather in certain areas throughout the year, for breeding, to lay eggs and other reasons. Sharks remember these annual patterns and return to these areas every year to take advantage of the population boom. Sharks will also remember human activity when it involves food supplies. Many species gather around fishing boats, for example, because they know fishermen might discard extra bait and small catches.