Today, I decided to write about turtles, but not the ones you might think. This week I will be spotlighting the only native fresh water turtle in Baja California Sur.
The Baja California Slider (Trachemys nebulosa) is an interesting turtle with a mysterious and rich history. These sliders rarely leave the water, yet they inhabit many isolated oases throughout the desert. So… how did a turtle that doesn’t leave the water spread across deserts? Well, one theory is that Baja used to be much wetter.
Thousands of years ago, this peninsula was much more like the mainland adjacent to Baja, with a good bit more rainfall. The turtles could have traveled from oasis to oasis until they arrived at their current range, or they could have stayed here unchanged since the peninsula broke off from Mainland Mexico, or somehow crossed the ocean. Another possibility is that they just evolved in Baja, although this theory is probably not the answer because a very similar — if not identical — population of turtles lives in Sinaloa and Sonora on the mainland.
These are all good theories, and it is unknown how these turtles got to Baja in the first place, but we do understand how they got into all of the isolated oases. In the 1700s, natives brought these turtles northward, from their tiny natural range of the Rio San Jose Valley to all over BCS, as a food source! Now, in the Rio San Jose Valley, these turtles are actually quite rare as a direct result of overhunting.
The Baja California Slider is the only native fresh water turtle in our area, but not necessarily the only fresh water turtle living here because there may be invasive species. For example, unfortunately, Red-Eared Sliders have been released in some water sources, competing with the Baja California Sliders, and diluting the bloodline with interbreeding. These two species are very similar-looking, and it is quite difficult to tell the difference between them. I have not yet had the pleasure of crossing paths with one of these amazing reptiles, and I will follow up with a column about identifying them once I find one, and figure out for myself what the differences are. chancestevens123@icloud.com