Instructions
Examine the claws on the turtle's front feet. Females have short, stubby claws that are the same length as the toes. Males have claws that are much longer than the toes.
Turn the turtle over and look at the length of the tail. Females have short, skinny tails, with the vent positioned nearer to the body. Males have long, thick tails, with the vent positioned towards the end of the tail.
Check the size. Females are the larger of the two sexes, although this varies depending on age and diet.
How to Tell if a Baby Red-Eared Slider Turtle is Male or Female
You can tell if your red-eared slider turtle is a male or a female by examining the length of the front claws, and the length of the tail. However, these characteristics don't develop until the turtle is at least 4 inches long from the front to the back of the shell. Red-eared sliders of all sizes are often sold in pet stores, so if you need to know the sex, it's best to pick a larger, older turtle.