Description ⁴

The carapace of this species can reach more than 40 cm (16 in) in length, but the average length ranges from 15 to 20 cm (6 to 8 in). The females of the species are usually larger than the males. They typically live between 20 and 30 years, although some individuals have lived for more than 40 years. Their life expectancy is shorter when they are kept in captivity. The quality of their living environment has a strong influence on their lifespans and well being.

These turtles are poikilotherms, meaning they are unable to regulate their body temperatures independently; they are completely dependent on the temperature of their environment. For this reason, they need to sunbathe frequently to warm themselves and maintain their body temperatures.

The shell is divided into two sections: the upper or dorsal carapace, and the lower, ventral carapace or plastron. The upper carapace consists of the vertebral scutes, which form the central, elevated portion; pleural scutes that are located around the vertebral scutes; and then the marginal scutes around the edge of the carapace. The rear marginal scutes are notched. The scutes are bony keratinous elements. The carapace is oval and flattened (especially in the male) and has a weak keel that is more pronounced in the young. The color of the carapace changes depending on the age of the turtle. The carapace usually has a dark green background with light and dark, highly variable markings. In young or recently hatched turtles, it is leaf green and gets slightly darker as a turtle gets older, until it is a very dark green, and then turns a shade between brown and olive green. The plastron is always a light yellow with dark, paired, irregular markings in the centre of most scutes. The plastron is highly variable in pattern. The head, legs, and tail are green with fine, irregular, yellow lines. The whole shell is covered in these stripes and markings that aid in camouflaging an individual.

Turtles also have a complete skeletal system, with partially webbed feet that help them to swim and that can be withdrawn inside the carapace along with the head and tail. The red stripe on each side of the head distinguishes the red-eared slider from all other North American species and gives this species its name, as the stripe is located behind the eyes where their (external) ears would be. These stripes may lose their color over time. Some individuals can also have a small mark of the same color on the top of their heads. The red-eared slider does not have a visible outer ear or an external auditory canal; instead, it relies on a middle ear entirely covered by a cartilaginous tympanic disc.

The main internal organs of these reptiles are the lungs, heart, stomach, liver, intestines, and the urinary bladder. A cloaca serves both excretory and reproductive functions.

Some dimorphism exists between males and females.

Red-eared slider young look practically identical regardless of their sex, making it difficult to determine their sex. However, there is another method to determine their sex, by inspecting the markings under their carapace. These markings will fade as the turtles age. It is much easier to distinguish the sex of adults, as the shells of mature males are smaller than those of females. Male red-eared sliders reach sexual maturity when their carapaces' diameters measure 10 cm (3.9 in) and females reach maturity when their carapaces measure 15 cm. Both male and females reach sexual maturity at five to six years.
The male is normally smaller than the female, although this parameter is sometimes difficult to apply as individuals being compared could be of different ages.

Males have longer claws on their front feet than the females; this helps them to hold on to a female during mating and is used during courtship displays. The male's tail is thicker and longer. Typically, the cloacal opening of the female is at or under the rear edge of the carapace, while the male's opening occurs beyond the edge of the carapace. The male's plastron is slightly concave, while that of the female is completely flat. The male's concave plastron also helps to stabilize the male on the female's carapace during mating. Older males can sometimes have a dark greyish-olive green melanistic coloration, with very subdued markings. The red stripe on the sides of the head may be difficult to see or be absent. The female's appearance is substantially the same throughout her life.

Fontes e Créditos

1. (c) Aleksandar, alguns direitos reservados (CC BY-SA), uploaded by Aleksandar
2. (c) E65vern, alguns direitos reservados (CC BY-SA), http://commons.wikimedia.org/wiki/File:Red_eared_slider_shell.jpg
3. (c) Pierre Fidenci, alguns direitos reservados (CC BY-SA), http://commons.wikimedia.org/wiki/File:Trachemys_scripta_elegans02.jpg
4. (c) Wikipedia, alguns direitos reservados (CC BY-SA), http://en.wikipedia.org/wiki/Red-eared_slider

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