Red-eared Slider
Trachemys scripta

Size:  5 - 8 in (along carapace)
Statewide.  Red-eared sliders are the most common freshwater turtle in Oklahoma, found in nearly every pond, lake, and stream. Also commonly encountered on the pet trade. Called sliders for their nature of quickly diving or sliding into the water from basking on a bank or log, sometimes basking in large numbers, often stacked one on top of another. They are easily identified by having an orange or red patch behind each eye, though adult males become extremely dark and lose this characteristic feature. Although extremely common in farm ponds, and hated for fear of eating the fish, the truth is that their diet consists heavily of aquatic vegetation and algae and invertebrates. They will however eat the fish that are not capable of swimming well, such as those that are sick, dying, or already dead. Consider these turtles the "maid service" of a pond, actually making the pond healthier by helping to eliminate disease.
Dark plastron of the red-eared slider.