Spotted turtles are native to the Southeastern United States. They inhabit bogs (swamp like areas), but can also be found in fresh still water. The spotted turtle is endangered due to habitat loss and the constant threat of being collected and placed into the pet trade. However, we are lucky enough to have these little creatures hatching and thriving here at the Zoo and in other zoos around the country.
In the month of December, the Oakland Zoo welcomed a few more spotted turtles to the family, and another just last week on January 31, 2013. Wayne and Gladys Valley Children’s Zoo Herp and Invert Keeper Adam Fink, fills us in about the most recent hatchlings as well as shares more facts about the spotted turtle.
A spotted turtle egg is about the size of a large grape, and unlike bird eggs that need to be rotated during incubation, reptile eggs must be kept in the same position as they were laid. This is because the embryo orients itself in the egg and turning the egg during this time could do much damage and kill the tiny turtle. Keepers are able to make an educated guess on whether the hatchling is male or female based on the temperature at which eggs are incubated. Females will result to warmer temperatures and males in cooler temperatures. “Like crocodilians, turtles can communicate to each other through the egg cases. This is why both species will have mass hatchings in the wild. The turtles or crocodilians will let each other know when they are ready to hatch and they all start hatching together. This is so that there is a better chance that at least some of the hatchlings will make it to the safety of the water,” says Adam.
Another interesting fact that Keeper Adam shared with us is that turtles, like all egg laying species, have egg yolks, which serve as nutrients for the developing embryo. However, unlike other eggs, the yolk is on the outside of the shell. The bottom of the shell has a small slit where the turtle comes out when ready to hatch. Once it hatches, the turtle will absorb the yolk sac, which in turn will close up that slit. If needed, the baby turtle can live off of the absorbed yolk for up to a few weeks.
Fink says the Oakland Zoo had about twenty spotted turtles hatch on site, with some continuing to live in our exhibit and some that have gone to join other zoos accredited by AZA, which is the Association of Zoos and Aquariums. Eight of the thirteen currently on exhibit have been born here at the Zoo.