Pond Slider (Trachemys scripta)
by Jeff LeClere
PROTECTED. It is illegal to kill or collect this species by law in Iowa. This is formerly a species of special concern in Iowa. Sightings along the Mississippi River and other large rivers north of Muscatine are needed.
This turtle is also called the red-eared turtle. Adults range from 5 – 11 1/2 inches in carapace length (Conant and Collins, 1991). Males are at the smaller end of this range whereas females grow to the larger size. The carapace is greenish with yellow stripes in each scute. Mature turtles may have as few as one, but young turtles have many. There may be dark blotches and lines on the carapace as well. There is no vertebral keel. The underside of each marginal is marked with a dark spot. The plastron is yellow with a large black spot on each scute. Some of these spots are ringed with black borders.
The ground color of the skin is green with bright yellow stripes on the head, limbs, and tail. The yellow stripes on the head are wide and reach the eyes and the snout. The most prominent feature of this species is the bright red bar behind the eye. It is an excellent field mark and can be readily seen with binoculars. Old males sometimes become melanistic. These specimens are black and gray. There are no bright markings at all on the skin or shell. Males have very long front claws and longer, thicker tails with a cloacal opening that extends past the edge of the carapace. Females have shorter front claws, shorter, thinner tails and their cloacal openings do not extend past the edge of the carapace. The young are similar to adults, but brighter (especially in shell coloration) and are 7/8 – 1 1/8 inches at hatching (Conant and Collins 1991).
The subspecies ranging into Iowa is the red-eared slider, Trachemys scripta elegans.
The red-eared slider naturally lives in southeastern Iowa. They follow the Mississippi north into Iowa and are found in the four large southeastern rivers connected to the Mississippi. Populations have been introduced throughout Iowa due to the release of pet turtles. Red-ears found anywhere but southeastern Iowa are probably such turtles.
Pond sliders are found in the mighty Mississippi and large southeastern Iowa rivers. Nearby ponds and sluggish backwaters are favorite haunts.
The red-eared slider can most readily be seen enjoying its favorite pastime: basking. They emerge from hibernation in April and retire into hibernation in October. Adults overwinter at the bottom of the river or pond in the mud. During their active period, they spend time basking interspersed with foraging for food in the water. Often there will be one or more prime basking sites where many turtles will sit upon one another, sometimes up to three in a stack. Red-eared sliders recede to the bottom of the wetland to spend the night.
Breeding occurs in the late part of April. The male swims behind a female as she moves to shallow water. Then he swims past the female and positions himself directly in front of her facing her head-on. Stretching out his forelimbs, he vibrates his long front claws along the females cheeks. Many times she may respond by backing away and swimming onward and thus the male follows and repeats the courtship behavior. When she is ready to breed, she may stroke his forelimbs with her claws. The male mounts the female from behind using his claws to secure his position. Then he moves his tail under hers to breed.
The females are ready to lay their eggs in late May or June. At this time, many females can be observed seeking out their nesting sites which may vary considerably in distance from their aquatic home. Often, females must cross roads to reach their destination and unfortunately are hit by motorists. Females mainly choose areas of loose sand or soil that gets plenty of sunshine. She begins by digging a flask shaped nest. She deposits about 8-15 eggs, fills the enclosure in, and makes her way back to her home. Sex determination is dependent upon temperature with mostly females resulting at temperature of 84 degrees and up and mostly males below that temp. Depredation upon turtle nests are extremely high, mostly by mammals which are able to dig up the leathery shelled eggs.
The young turtles hatch in late August, but the young may overwinter inside the nests and emerge the following spring. They will be ready to reproduce at about three to eight years of age (Ernst, Lovich and Barbour, 1994).
Red-eared sliders are omnivorous. The young are mainly carnivorous and they become more herbivorous as they become older (Ernst, Lovich, andBarbour, 1994). Because they have a fixed tongue, they cannot easily swallow food on land. Their food must be obtained and eaten in the water. Sliders (especially younger ones) spend time chasing fishes, aquatic insects, tadpoles, frogs, crayfish, snails, and other aquatic animals. They also consume carrion and will browse on different forms of aquatic vegetation. The taste for the herbivorous portion of their diet is acquired with age; the young are mostly carnivorous.