Written by: Graeme Lyons

01 December 2024

Red-eared Terrapins to be removed from the website until confirmed breeding is observed

Although "your list, your rules” is at the core of pan-species listing, there is a line that we do not cross—we do not count non-native species in captivity or that have escaped/been released from captivity if they do not go on to breed, naturalise and/or form a viable population. If they did though, then we would add them: such as the plethora of naturalised species found in hot houses, or Ring-necked Parakeets for example. But we do not count the individuals that have escaped or been released until they go on to breed–or else we’d be counting dogs in parks and escaped monkeys from zoos.

That’s why it’s been important to get to the bottom of whether there is any evidence at all that Red-eared Terrapins are breeding in the UK. We listened and went away and did some research. Here is what we got back from Amphibian and Reptile Conservation:

We have been made aware of a few cases where people have reported burrow digging and even egg laying in the wild in the UK, but no confirmed hatching success. It is possible that there could be hatching success in a semi-wild situation, e.g. an outdoor vivarium where the substrate is heated, but probably very unlikely there would be successful hatching in the wild, certainly not on a sustained basis year after year. There have been some studies modelling the potential range of the species/subspecies and from memory this indicates that it would take several more decades of climate warming before the species is likely to establish. The Turtle Tally project will be able to give you more information.

Turtle Tally researches released pet terrapins in the UK through a citizen science survey. According to Turtle Tally (see their ‘About us’ for more details), terrapins (freshwater turtles) are widespread across Europe and released pets have had an impact on those populations due to competition for food and basking sites. The European Pond Turtle Emys orbicularis was native in the UK c8,000 years ago but became extinct due to climatic changes, so there are no native terrapins in the UK. In Europe, released terrapins out-compete native species: whilst this is not a factor in the UK it is unclear how they impact the environment and what the welfare considerations are for them. Turtle Tally responded:

In regards to evidence of breeding, in the six years I have been running my research work, I haven’t had anything which categorically proves that they have successfully hatched here. A few individuals who are hobbyists with outdoor enclosures have had them hatch but these are manipulated environments facilitating what is needed. Otherwise any reports (very rare) have not provided accompanying evidence.

Therefore Red-eared Terrapin will be removed from the PSL checklist, along with the other three species of freshwater turtle currently included, and any records of these will automatically be removed from people's lists. If confirmed breeding occurs they can always be added back, but this is unlikely to happen anytime soon based on the above.

Of course, by all means keep recording them if you see them. Let Turtle Tally know about any observations of freshwater turtles in the UK to help prevent the spread of these non-native species in our water ways: non-native species are the second biggest cause of extinction globally, after habitat loss.