Also known as brown sharks, sandbar sharks exhibit the typical appearance and behavior that people associate with sharks. They are ram ventilators, which means that they must constantly swim to move water across their gills. While these sharks swim much faster and are more agile than the sandtiger sharks, they seem almost afraid of the divers and will avoid any type of interaction with them. Sandbar sharks bear live young and have eggs that develop internally. Litter sizes generally average six to 13 pups; females reach maturity at about 12 to 15 years of age As with most sharks, they have very low reproductive rates and are vulnerable to population decline if overfished.