User:Ariel Kruger/sandbox

From Citizendium
< User:Ariel Kruger
Revision as of 21:23, 6 November 2010 by imported>Ariel Kruger
Jump to navigation Jump to search

Loggerhead Sea Turtle

The loggerhead sea turtle (Caretta caretta) is an omnivorous, ectothermic, marine reptile that is the most widely distributed of all sea turtle species. Named for its broad head, loggerheads are the largest hard-shelled turtle in the world, weighing 250 pounds and reaching lengths of about 35 inches (the Leatherback turtle is the largest sea turtle, but it’s carapace is covered by skin instead of a hard-shell). Life expectancy in loggerheads is about 50 years, although actual records of age are scarce. The loggerhead sea turtle has a distinct heart-shaped shell that is reddish-brown in color. The turtles’ hard-shell protects them from predators, such as sharks. Loggerheads are known to feed on jellyfish, barnacles, shellfish, and occasionally seaweed. Adults can reach speeds up to 15 miles per hour.

Habitat

Loggerheads spend most of their lives in shallow, coastal waters, and have been found in the Atlantic, Pacific, and Indian Oceans, as well as the Mediterranean Sea. Loggerheads can live in both temperate and warm waters. Habitat preference may change depending on life stage. Hatchlings tend to float in open water, while juveniles prefer to remain in coastal areas.

Nesting Habits

Female loggerheads come ashore during the nesting season, which generally lasts from May to September, but male loggerheads never return to land after birth. Females may nest every year, although most nest every two to three years. Loggerheads may migrate long distances to nest at preferred sites, usually areas they return to each time they nest. Each season, a female loggerhead will come ashore an average of four times to nest, laying about 100 eggs in each clutch. Loggerheads seem to prefer nesting above the high tide line and on steeper beaches.[1]
Females emerge from the water to nest at night. Once they find a suitable spot to lay their eggs, the female begins digging a body pit by moving sand with her flippers. Once she is situated, she uses her hind flippers to dig a nest, into which she deposits her eggs. After the eggs are laid, the female will use her hind flippers to fill the nest with sand and then will return to the water. The entire nesting process may take up to three hours.
Hatchling development is dependent on nest temperature. Loggerheads, along with other oceanic turtles, exhibit temperature sensitive sex determination (TSD). The pivotal temperature, the temperature at which a 1:1 ratio of females and males are produced, occurs around 30°C, [2] although this temperature varies depending on location. Females are produced at temperatures above the pivotal temperature, while males are produced at temperatures below the pivotal temperature.

  1. 1. Fish MR, Cote IM, Gill JA, Jones AP, Renshoff S, Watkinson AR. Predicting the impact of sea-level rise on Caribbean sea turtle nesting habitat. Conservation Biology 2005;19(2):482-491.
  2. 2. Chaloupka M, Kamezaki N, Limpus C. Is climate change affecting the population dynamics of the endangered Pacific loggerhead sea turtle? Journal of Experimental Marine Biology and Ecology 2008;356(1-2):136-143.