Here’s why researchers say you shouldn’t release your pet turtle into the wild

California’s native Western Pond Turtle tends to lie low during the winter. But in the warmer months, it’s at its most active. You might occasionally spot the turtle basking on a sunlit log around freshwater, like the American and Sacramento rivers, or places where watershed restoration is happening, like UC Davis’s arboretum. 

And during those warmer months, UC Davis conservation biologist Brian Todd sets out with a team to study its local population. 

To do that, they’ll capture turtles in baited hoopnet traps set along bodies of water like Putah Creek. They’ll then take measurements of the captured turtles before returning them. Todd says it’s a way to estimate the size of the population and their survival. 

But they’re not the only turtles out there. The non-native red-eared slider — most often bought as pets and then later released by their owners into freshwater ecosystems — are becoming a more frequent sight in the same places where Western Pond Turtles make their homes. 

And unlike the native species, Todd says these turtles aren’t too shy. 

“If you're walking in an urban or suburban park and you notice a bunch of turtles on a log, the first ones that jump in seem to always be our native Western Pond Turtles,” Todd says. “The ones that will hang out the longest are non-native species like the red-eared slider.”

CapRadio spoke with Todd about how Western Pond Turtle populations are doing as they compete with invasives like the red-eared slider and other threats.

This interview has been edited for clarity and length. 

How did Western Pond Turtles become a focus for you? 

When I moved here about 15 years ago, I had already had a lot of experience working with reptiles in the Southeastern United States. I was pretty shocked when I moved to California and found out that there's only one species of freshwater turtle native to the entire state, and that is the Western Pond Turtle.

Now, it turns out, as we understand it now, the Western Pond Turtle is actually two very closely related species that look identical — The Northwestern Pond Turtle and the Southwestern Pond Turtle. It would be very hard for the average person to tell apart. They're the only two species in the entire state that live in our fresh waters natively.

To me, that's really cool because it means that any type of water that you are working in, whether it's a stream, a lake, a cattle pond, sometimes sewage treatment plants, if there's a turtle and it's native, it's got to be this species.

I'm also a conservation biologist. And when you look at wildlife declines globally, two of the hardest-hit species are amphibians and turtles.

And when I say hardest hit, what I mean is that those are the species that are declining the fastest, that are the most imperiled, and that we're at the most jeopardy of losing if we don't better manage our natural resources, our habitat, and the problems we're creating for them. 

From left to right: Research assistants Ben DeDominic and Stan Spafford, alongside wildlife biologist Laura Kojima, remove a hoopnet trap meant to capture Western Pond Turtles along Putah Creek on Aug. 5, 2025.Manola Secaira/CapRadio

How would you describe the Western Pond Turtle? I’m curious about what sets it apart from other turtles, and what it means for local ecosystems. 

One of the things I find really interesting about the pond turtle is that it's sort of the anti-Gen-Z or anti-Millennial.

When I'm teaching my classes, I like to joke that if someone made a social media app for pond turtles, it would never succeed because they do not like being noticed. You're lucky to see one and most of the time, when you do see one, it's basking on a log. But as soon as it sees you, it jumps into the water. 

So they're a very shy species that doesn't particularly like being around people, being disturbed or being at risk from things like birds or mammals that may try and catch and eat them.

If you find Western Pond Turtles in a habitat in California, that’s also a good sign that it is a relatively high quality habitat. That's because native Western Pond Turtles seem to disappear first from a lot of areas. They need terrestrial habitat or land that's in good shape so that they can lay their eggs, so that they can bask. They need healthy rivers and streams so that they can feed and swim around and complete the rest of their lives.

So if you have a Western Pond Turtle in your local habitat, it's usually a great sign that there's a healthy ecosystem there.

But now, they’re seeing competition from other turtles that aren’t native. Can you tell me about what’s happening there? 

Here in California, we have red-eared sliders. They're a really common pet turtle. You can actually find them in pet stores in Davis and all over Sacramento. If you see the bright red patch behind the eye on the neck of the turtle, that's how you know it's not one of our native species — that’s the red-eared slider.

Unfortunately, people will buy them as pets, realize they can live for many, many years and when they no longer want them, they illegally release them outdoors.

The problem then is that those non-native turtles start to create their own populations in the wild and that causes challenges for our native wildlife. I think one of the reasons non-native turtles like red-eared sliders do so well when they're released into the wild is that they tend to be much more defensive. If you get your hands on one or if a predator is trying to eat it, they will bite back.

And when a non-native turtle is interacting with a native turtle, the non-native turtle probably has an edge. It probably has a leg up in terms of being able to bite at the native turtle and scare the native turtle away because our Western Pond Turtles are really shy. They like to hide and not be noticed.

UC Davis researchers Brian Todd (left) and Laura Kojima (right) take measurements of a captured Western Pond Turtle on Aug. 5, 2025.Manola Secaira/CapRadio

What other challenges are Western Pond Turtles facing in our area? 

The Western Pond Turtle is really broadly distributed from Baja Mexico up through California into Oregon and Washington State. 

And at one time, it was pretty abundant across most of its range, but it has declined dramatically in the last 30 years or so. So much so that Washington State protects the turtle and Oregon protects the turtle.

There are some minor protections here in California in cases like development. But it is not a threatened or an endangered species under state law or under federal law. However, just last year, the U.S. Fish and Wildlife Service, proposed a rule listing the Western Pond Turtle, both species of the Western Pond Turtle, as threatened, which would give it a lot of protection provisions. 

There are a lot of reasons it has declined just like many wildlife. They're affected by how we use land. So, if there are relatively pristine or clean streams that run through areas and we end up developing those areas and putting in housing or shopping malls or parking lots, we end up changing the way that landscape looks and functions. 

Another thing that has really threatened Western Pond Turtle populations are roads. They have to come out and lay their eggs on land. And occasionally, if their water dries up, they might head over land to find other places. When they encounter a road, they usually lose. 

And looming in the background for all of our biodiversity, whether it's plants, animals of any kind, is climate change.

What do you hope for the future of Western Pond Turtles in our region? Is there something that you wish could change or that we could focus on?

I think an important step would be for people to recognize the potential harm that releasing unwanted pets or non-native wildlife can pose to our native species like the Western Pond Turtle. Not releasing increasing wildlife, not feeding wildlife, is a good way to keep wildlife wild and to keep our native species in place.

The best alternatives are to offer it up for adoption on places like Craigslist or Facebook Marketplace, or other kinds of online ad services. And if you can't find anyone that's willing to adopt the animal that you no longer want, you can also reach out to organizations like the Northern California Herpetological Society or local turtle rescue groups. 

My hope for the Western Pond Turtle is that there will be enough rural or wilderness places for the pond turtle populations to do really well, and that our urbanized and suburban waterways will continue to recover and improve as we manage impacts and restore waterways.