The red-eared slider is a medium-sized aquatic turtle with a patch of red on each side of its head. The carapace (upper shell) is olive brown with numerous black and yellow lines. The plastron (lower shell) is yellow, with each scute (shell scale) normally having a large dark brown or black blotch. The exposed skin is dark green with narrow black and yellow lines. A wide red or orange stripe is present on each side of the head behind the eye. Old individuals sometimes have an excess of black pigment that obscures most of the yellow stripes on the shell and skin and the red stripe behind the eye. This condition is known as melanism and is associated with old males.
Similar species: The similar-looking eastern river cooter occurs in the southern half of the state. It is distinguished by a yellow, typically Y-shaped mark behind each eye, and by the lower shell, which is normally yellow; it may either lack dark markings completely or have gray-brown markings along the scute seams, especially toward the front.
The yellow-bellied slider (T. s. scripta), a subspecies that is native to southeastern states but is not native to Missouri, is increasingly being found in Missouri, especially at high public use conservation lands. It lacks the red "ear" marking and somewhat resembles the eastern river cooter. The plastron is mostly yellow with black spots along the edges. It appears that most of these yellow-bellied sliders were released pets. Efforts to remove this slider subspecies are being taken to reduce impacts to native turtles of Missouri. Never release pets into nature.
Missouri has several native members of the pond and box turtle family; the red-eared slider is one of the most common and widespread in our state. Other aquatic and semiaquatic relatives include painted turtles, the western chicken turtle, map turtles, and Blanding's turtle. Many of them have limited distributions, which can help with identifications.
Adult upper shell length: 5–8 inches; occasionally to 12 inches. Adult females have larger shells than adult males.
Statewide, except for a few northern counties.
Habitat and Conservation
The red-eared slider occurs in a wide variety of aquatic habitats, but it prefers a mud bottom, plenty of aquatic plants, and abundant basking sites. This turtle lives in both natural waters (including rivers, sloughs, and oxbow lakes) and human-made waters (such as ditches, ponds, and reservoirs). Red-eared sliders living in the Mississippi River prefer slow, muddy habitats.
Through most of Missouri, this turtle becomes active in March, when the air temperature reaches 50°F or higher, and it remains active until mid-October. A population of sliders studied in cooler climates in northeastern Missouri were active from late April to the middle of September.
On sunny days, basking in the sun on logs or other objects projecting from the water begins in midmorning and generally lasts until midafternoon. Sometimes a log is covered with many basking sliders.
At night, red-eared sliders will sleep while resting on the bottom or floating on the water's surface.
They are often seen moving about on land, especially males moving between ponds and females searching for nesting sites.
Individuals overwinter underwater buried in the mud or under a cut bank.
Red-eared sliders eat a wide range of both aquatic plants and aquatic animals. Young individuals often consume more animal foods, but as they age, their diet shifts to more plant foods. Foraging takes place in early morning and late afternoon.
During the 13- or 17-year mass emergences of periodical cicadas, sliders and other turtles feed heavily on this available and abundant resource.
This species is usually the most abundant turtle observed in Missouri, especially in ponds and lakes. In Missouri, it is one of the more commonly encountered and widespread aquatic members of the pond and box turtle family.
Elsewhere in the world, where they are not native, red-eared sliders have been released or have escaped into the wild. In parts of Europe and Asia, their populations are damaging populations of native species and are deemed invasive. Importing them is banned in several nations.
Within North America, young red-eared sliders were once commonly sold as pets in dime stores and pet shops. When it became known that the turtles and their water can harbor salmonella bacteria, and that humans handling the turtles might be affected, sales of the turtles mostly ended.
Courtship and mating occur between mid-March and mid-June; this species might also breed in autumn as well. Egg-laying occurs between April and mid-July, with most eggs laid in May and June in Missouri. Females ready to lay their eggs leave the water and search for a suitable egg-laying site. Throughout their range, females lay up to 30 eggs per clutch (with an average of 10 eggs in a clutch). Females leave the water and lay up to 22 eggs in a clutch. Some females may lay more than one clutch during a season. Hatching usually takes place in late summer or early autumn, with incubation probably lasting some 68–70 days. Young turtles usually remain in the nest and emerge the following spring.
Males may attain maturity at 4 or 5 years of age, but possibly up to 7 or 8 years in colder habitats and ranges. Females become mature at the age of 13 or 14. Individuals have been reported to live up to 37 and 49 years of age in captivity.
Before the mid-1970s, millions of baby red-eared sliders were sold as pets, most of them dying due to lack of proper care. The sale of these turtles was curtailed because of possible salmonella contamination that could be transmitted to humans by handling the turtles or the water in which they were kept.
Red-eared slider hatchlings are still being produced by turtle “breeders” in several southern states. The majority of these young turtles are destined for the pet trade in Europe and Asia. Many are eventually released or escape to the wild and, as invasive species in those regions, are causing a decline of native species, especially in southern Europe. Their importation has been banned in several countries.
The name “slider” comes from their habit of sliding quickly into the water from their basking spots.
In their native land, these turtles fill a role of herbivore and mid-level carnivore. However, American-bred sliders are being supplied to the pet trade in Europe and Asia, where some have been released to the wild. There, they are causing a decline of native species, especially in southern Europe.
Because sliders and several other species of turtles eat a variety of plant materials, they aid in the dispersal of plant seeds.
Ecologists have noted that predator-prey relationships influence population numbers. One example is the periodical cicadas, which emerge all at once after spending 13 or 17 years underground. Red-eared sliders and other turtles, plus birds and many other predators feast on the swarming cicadas. But the feast is short-lived, not perennial, and the cicada numbers overwhelm their predators' ability to eat them all. Many, many cicadas survive and reproduce, and any individual cicada has a good chance of parenting a new generation.
The red-eared slider is a member of family Emydidae (the pond and box turtle family). This is one of the largest families of living turtles in the world. It comprises 12 genera, containing 52 species. In general, turtles in this family are small to medium sized and are adapted to a variety of habitats. This family includes several colorful species. Although the majority of species are aquatic (such as the red-eared slider), several kinds are either semiaquatic or have taken to life on land (for example, the box turtles). In Missouri, this family is represented by 7 genera with a total of 11 species and 1 additional subspecies.