Red-eared slider

The red-eared slider (Trachemys scripta elegans) is a semi-aquatic turtle of the family Emydidae, the best-known and most widely traded subspecies of Trachemys scripta. It is easily recognised by the red patch behind each eye, which gives the species its common name ("red-eared slider"), and by its green shell in juveniles, which darkens to olive or brown tones with age.

The shell usually measures between 12 and 20 cm, although some individuals exceed 30 cm; females are larger than males.

It is native to the south-eastern United States and north-eastern Mexico, where it lives in warm, slow-flowing fresh water: ponds, lakes, marshes and rivers, always with basking spots such as logs or emergent rocks. Because of the pet trade, it has been introduced to many countries in Europe, Asia and other continents, including Spain, where it is found as a feral population in rivers and wetlands, among them the River Tagus itself as it passes through Toledo.

It is omnivorous, although juveniles are more carnivorous and adults gradually become more herbivorous. It feeds on aquatic plants, algae, invertebrates, small fish and carrion.

Courtship and mating take place in the water between March and July. Females dig nests in the ground where they lay between 2 and 20 eggs, which take roughly 80 to 85 days to incubate. The hatchlings break out of the shell using a small "egg tooth" that they lose shortly after birth.

The red-eared slider is among the hundred most harmful invasive alien species in the world according to the IUCN, as it competes with native turtles for food and nesting sites. For this reason, Zoo Koki helps to raise awareness about controlling this invasive species around the River Tagus, stressing the importance of never releasing pets into the wild. It can live 20 to 30 years in the wild, and more than 40 in captivity.