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YELLOWBELLY SLIDER

Despite its name, Hilton Pond is a relatively recent addition to our family land holdings. Until 23 years ago, the property belonged to a succession of farming folks, including the McFarlands, Faulkners, and most recently Bobby Bolin--a native of nearby Hickory Grove SC. Bolin was a sidearm hurler for the San Francisco Giants, Milwaukee Brewers, and Boston Red Sox, and it was he who in 1982 sold us the old farmhouse and acreage that became Hilton Pond Center for Piedmont Natural History. We Hiltons actually grew up about ten miles down the road at Twin Cedar Acres, a four-acre tract just west of Rock Hill SC where 79-year-old Jackie Hilton still feeds the birds and tends to trees and shrubs we planted in our childhood. Not infrequently, the matriarch calls to report some unusual natural history occurrence, and such was the case this week when she and our younger brother Stan were digging up some old fence posts along the road east of the house. Seems that with one turn of the spade, Stan uncovered an unexpected surprise--a nestful of six inch-long Yellowbelly Sliders.

All text & photos © Hilton Pond Center

Yellowbelly Sliders are among the most common aquatic turtles in the southeastern U.S., and they are well-named. Adults and hatchlings alike have a bottom shell--the plastron--that is creamy lemon yellow in color (below), and they use its smooth surface to help them slide from riverbank to water at the first sign of potential trouble. Equally at home on ponds as they are along slow-flowing tributaries, Yellowbelly Sliders occur across the Coastal Plain from extreme southeastern Virginia to the Florida panhandle, and into the Lower Piedmont of South Carolina and Georgia. Some field guides show that Yellowbelly Sliders don't occur in our central Piedmont county of York, but Stan Hilton's shovel and observations we've made throughout the area indicate otherwise.

Stan found the baby turtles about four inches or so below the surface in relatively soft soil covered by grass. We were a bit confused as to why these "turtlets" were just appearing, since Yellowbelly females typically lay in May or June and eggs take about two months to mature. Hatching in mid-summer allows young turtles to crawl to the safety of a pond or lake, grow a little, and put on some fat before the onset of winter. It appears that the little sliders from the Hilton homestead were laid rather late in 2003 and simply stayed in their nest after breaking through leathery eggshells last fall. Stan undoubtedly encountered them this week just before they were ready to dig their way out of their subterranean winter home.

The distribution of Yellowbelly Sliders is actually much wider than it was historically and includes places as distant as Europe, Africa, and Asia. That's because millions of baby sliders were raised--or purloined from nature--and sold in pet shops here and abroad as "dime store turtles." Of the relatively small percentage that survived during captivity, many were dumped into local waterways when the owners tired of caring for them, and sliders are now considered to be invasive species in many parts of the world where they may crowd out native turtles.

According to the Center for North American Herpetology, there are actually four kinds of sliders; of these, three are closely related subspecies grouped under Trachemys scripta--a name that refers to the delicate script-like markings on the carapace (dorsal shell)--of young turtles (below). The Yellowbelly Slider, T.s. scripta is the nominate subspecies; the others are the Red-eared Slider, T.s. elegans (above right)--also once sold as a pet--and Cumberland Slider, T.s. troostii, which is found in roughly the same geographic area as the Yellowbelly.

All three subspecies have yellow plastrons. T.s. scripta has a vertical yellow bar behind the eye that joins two horizontal stripes that extend down the neck, while the Cumberland lacks the vertical bar, may have an orange-yellow spot, and has narrower stripes. The Red-eared Slider typically has a prominent scarlet spot on the side of the head. It's possible that all three subspecies interbreed, so sliders in general present an interesting taxonomic puzzle and once were even considered to be in the same genus as Painted Turtles, Chrysemys picta, which also occur on Hilton Pond.

Young sliders have well-defined markings that blur with age. In fact, the carapace of an old Yellowbelly Slider may be almost black (above), and even the yellow head markings become less prominent. All six hatchlings from Rock Hill had similar carapace scripting, but close examination showed subtle differences as unique as human fingerprints. Although each plastron had two anterior bulls-eye markings (below), the shape and number of ventral spots were distinct and allowed identification of specific individuals.

Adult Yellowbelly Sliders typically grow to lengths of 5"-8"--a few old individuals have had shells a foot in length--with males being somewhat smaller than females. Mature males have long foreclaws with which they stroke the female to get her attention during courtship, which includes a sort of slow-motion underwater ballet by the male. After mating, the female eventually crawls to an appropriate but sometimes distant spot where she uses her hind legs to excavate a vase-shaped nest in the earth. Then she lays four to 24 round, white eggs that resemble small ping pong balls, covers them, and makes her way back to her aquatic home--not knowing that her deposit is often dug up and eaten by Raccoons within the first 24 hours. Some females apparently lay two or three clutches per year, with the latter being produced in July or August--which likely was the case with the nest Stan found in Rock Hill.

Sliders become inactive when temperatures drop below 50 degrees F, so basking turtles we occasionally see on warm days in midwinter are Painted Turtles rather than Yellowbellies. Sliders sleep underwater at night, either resting on the bottom or filling their throats with air as a flotation device. Younger sliders such as our recent hatchlings are primarily carnivorous, with about 70% of their diet being small fish, snails, aquatic insect larvae, and occasional dead animal matter. Feeding preferences flip flop in adults, which eat up to 90% plant material that includes water lilies and duckweed. Young sliders are consumed by big fish, large turtles, and herons, and since the slider's shell is unhinged and doesn't close all the way (below), even in adults it provides scant protection from mammalian predators such as Raccoons, foxes, and domestic dogs. Nonetheless, the biggest danger for Yellowbelly Sliders is habitat loss--and fast-spinning automobile tires when females come ashore to lay eggs.

Although we would never transport an adult slider very far--one study showed they are exceptionally faithful to their home ranges--we decided to bring the Rock Hill turtlets back to York for release in Hilton Pond. We have a couple of Yellowbelly Sliders that ply our local waters, but the population is much reduced from a decade ago. We suspect the five-year drought that finally ended in 2003 played a role, and that a family of River Otters that visited in the winters of 2001 and 2002 may have harvested some of our turtles as they slumbered on the pond bottom. In any case, we believe the recent hatchlings are a lot better off being deposited in Hilton Pond than they would be had they tried to navigate the 200 yards of roadways and driveways between where they hatched out and the nearest aquatic habitat in Rock Hill. If our six new sliders make it here in York, we'll try to recapture them in a few years to see if they've retained those distinctive ventral markings or worn them off by sliding their Yellowbellies down the muddy banks of Hilton Pond.

All text & photos © Hilton Pond Center

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