A loggerhead turtle, Caretta caretta, with sharksuckers in the northern Bahamas. The loggerhead turtle is one of only seven species of marine or sea turtles in existence today. The loggerhead's name refers to the size of its head, which is larger in proportion to its body than the head of other marine turtles. Adult female loggerheads can weigh as much as 300 pounds, and males may grow even larger. The head and upper shell (carapace) are a dark reddish-brown; the flippers and lower shell (plastron) are light yellow. The outer layer of plates on the shell and head are called scutes. The number and position of the scutes distinguish the various species of marine turtles. In coastal waters, the loggerhead feeds mainly on whelks (large marine snails), crabs, fishes and benthic organisms (those living on the bottom of the sea), such as sponges and algae.