Loggerhead Sea Turtle

The loggerhead sea turtle is the world's largest hard-shelled turtle, slightly larger at average and maximum mature weights than the green sea turtle and the Galapagos tortoise. It is also the world's second largest extant turtle after the leatherback sea turtle. Adults have an approximate weight range of 80 to 200 kg (180 to 440 lb), averaging around 135 kg (298 lb), and a straight-line carapace length range of 70 to 95 cm (28 to 37 in). The maximum reported weight is 545 kg (1,202 lb) and the maximum (presumed total) length is 213 cm (84 in). The head and carapace (upper shell) range from a yellow-orange to a reddish brown, while the plastron (underside) is typically pale yellow. The turtle's neck and sides are brown on the tops and yellow on the sides and bottom.

The loggerhead sea turtle has a cosmopolitan distribution, nesting over the broadest geographical range of any sea turtle. It inhabits the Atlantic, Indian, and Pacific Oceans and the Mediterranean Sea.

In the Atlantic Ocean, the greatest concentration of loggerheads is along the southeastern coast of North America and in the Gulf of Mexico. Very few loggerheads are found along the European and African coastlines. Florida is the most popular nesting site, with more than 67,000 nests built per year. Nesting extends as far north as Virginia, as far south as Brazil, and as far east as the Cape Verde Islands. The Cape Verde Islands are the only significant nesting site on the eastern side of the Atlantic. Loggerheads found in the Atlantic Ocean feed from Canada to Brazil.

The loggerhead sea turtle is omnivorous, feeding mainly on bottom-dwelling invertebrates, such as whelks, conchs, bivalves, and horseshoe crabs. It has a greater list of known prey than any other sea turtle. Other food items include sponges, corals, sea pens, polychaete worms, tube worms, sea anemones, cephalopods, barnacles, brachiopods, amphipods, isopods, Portuguese men o' war, insects, bryozoans, hydrozoans, sea urchins, sand dollars, sea cucumbers, starfish, tunicates, fish (eggs, juveniles, and adults), hatchling turtles (including members of its own species), algae, and vascular plants. During migration through the open sea, loggerheads eat jellyfish, floating molluscs, floating egg clusters, squid, and flying fish.

Loggerhead sea turtles observed in captivity and in the wild are most active during the day. In captivity, the loggerheads' daily activities are divided between swimming and resting on the bottom. While resting, they spread their forelimbs to about midstroke swimming position. They remain motionless with eyes open or half-shut and are easily alerted during this state. At night, captives sleep in the same position with their eyes tightly shut, and are slow to react. Loggerheads spend up to 85% of their day submerged, with males being the more active divers than females. The average duration of dives is 15–30 min, but they can stay submerged for more than ten hours, longer than any other air-breathing marine vertebrate. Juvenile loggerheads and adults differ in their swimming methods.

Female loggerheads first reproduce between the ages of 17 and 33, and their mating period may last more than six weeks. They court their mates, but these behaviors have not been thoroughly examined. Male forms of courtship behavior include nuzzling, biting, and head and flipper movements. Studies suggest females produce cloacal pheromones to indicate reproductive ability. Before mating, the male approaches a female and attempts to mount her, while she resists. Next, the male and female begin to circle each other. If the male has competitors, the female may let the males struggle with each other. The winner then mounts the female; the male's curved claws usually damage the shoulders of the female's shell during this process. Other courting males bite the male while he is attempting to copulate, damaging his flippers and tail, possibly exposing bones.

Many human activities have negative effects on loggerhead sea turtle populations. The prolonged time required for loggerheads to reach sexual maturity and the high mortality rates of eggs and young turtles from natural phenomena compound the problems of population reduction as a consequence of human activities.