Why do my turtles climb on top of each other? Is it mating or heat?

It may be due to coloring from the food or tank furniture. It may also be a water quality issue. Look both turtles over for any signs of obvious injury. If they are both female, you may have some aggression/territoriality issues which may require a significantly larger tank or separation.

Separate out the aggressive one. It could be nipping due to hunger, stress or aggression. Consider hand feeding to avoid accidental bites as well as dividing them into two tanks to provide more space. As they mature, they will require a significantly larger space. This number of turtles ideally will need a tank in the hundreds of gallons range or a small pond. A general guideline is 10 gallons per inch of turtle. Sexing turtles is easier when they are mature. Without knowing the species, it can be difficult, but in general, females are larger than males. Males have a shorter, thicker tail in comparison and usually have longer front claws. A female will have a flat plastron whereas the male will have a slight concavity. Males have a v-notch at the rear of the carapace to accommodate the tail when mating. Lastly, you can check the cloaca, or vent. Females will have a rounder vent closer to the body whilst males will have more of a slit farther down under the tail. All these differences are best seen when comparing two turtles or a proven pair.

Thanks for reaching out about Sheldon. This sounds like a common breeding behavior, to attract mates and warn off competing males. Females probably release pheromones in the water, as a signal for breeding potential. Unusual season for this but might be stimulated by warmer temperatures. Good luck.

Thanks for reaching out about Leo. Many aquatic turtles won't bask if they feel safe. Also if the air is cool, and the heat lamp over the basking site not adequate, they might be warmer in the water. If the heat lamp is too close and too hot, Leo might feel uncomfortable. Check out those parameters and fix any problems. Good luck.

Turtles will bask in a variety of positions to maximize heat and UVB absorption. If she is behaving normally otherwise, there is likely no cause for concern. Monitor for lethargy, difficulty breathing, "gaping" (opening and closing mouth), blowing bubbles or discharge from the nose or mouth, decreased appetite or lopsided swimming. See your veterinarian or an experienced herp veterinarian if any of these symptoms develop.

You should separate them. When confined in a tank or other small area, red ear sliders (RES) can exhibit a dominating behavior towards other tank mates. Turtles can easily injure one another with their bites. Males may endlessly pursue females which is probably what is happening with yours. Harassment can escalate to serious aggression such as fighting which can result in cuts, loss of limbs or even death. Adding a new turtle may immediately cause aggression and bullying, while some turtles harass more after they develop sexually. Males seem to be more likely to fight each other and harass females. Wish I had an easier solution for you but separating them would be best.

Thanks for reaching out. Whether they get along depends on the sex of the other turtles, the size of the tank, having multiple haul-out locations for bathing, water and basking temperatures/UVB exposure and food access. Hiding spots should be multiple also. All animals should be disease free prior to introduction. Good luck.