Keeping Turtles in an Outside Pond in the UK

Ponds in a back garden generally fall into two categories, wildlife and koi/goldfish ponds. The former is a great pond to have, but isn’t exactly an interactive experience, and the second can be rewarding, but an increase in cats, herons and other predators means that people are often looking for something that bit different to keep in a pond.

There are a few great reasons to consider keeping a turtle pond, firstly there is few other pond inhabitants that will climb out the water when they see you coming (with the food container), secondly in the right set up they are surprisingly low maintenance, and thirdly you may well be offering an unwanted pet a home.

At any point in the UK there are thousands of turtles looking for new homes. Unwanted pets that have outgrown the tiny tanks they were sold with, many will be dumped in rivers lakes and canals. The lucky ones will survive, but as an invasive species some counties are draining waterways to remove the turtles and euthanizing them as new homes can’t be found.

Turtles can make a great inhabitant of a residential pond. If you get the right one they are adapted to our climate and will happily hibernate under ice, it’s a brave heron or cat that will take on a fully grown foot long turtle, and on sunny days there is nothing nicer than seeing a turtle or two basking at the side of the pond. Many keepers happily cohabit turtles and fish, and whilst tadpoles may be snacked on, frogs seem to remain unharmed.

It’s well worth designing the pond specifically for turtles, in warm weather as long as they’ve got some way to get out easily and an escape proof fence then they’ll bask happily jump in to have a swim round and generally take care of themselves. But once the cold weather hits you need the pond to be specifically designed so they can safely hibernate and survive to come out for spring.

Hibernation

The study of turtle hibernation in UK ponds is still a relatively new field, but recently the information has been coming together, all thanks for this research goes to Roman Muryn (C. Eng MRAeS).

A turtle has the ability to survive for months underwater, and it’s worth looking at these briefly.

1. They have a lung capacity 10 x larger than comparably mammals. They also only have 10% of the metabolic rate. Meaning that they have 100 x the capability to survive. Scientists studying the cold water survival of turtles have shown that their heart slows down and only pumps just enough to keep them alive. In short they only breathe when they need to.
2. Their liver is 4% of their body mass and forms a huge energy reserve to get them through the winter.
3. Most turtles can take up oxygen in other ways than their lungs, including via the cloaca, the skin and via throat pumping.
4. They can use the calcium from their shells to buffer the lactic acid that builds up whilst they are under water over winter.

There are two types of species when considering hibernation.

1. Riverine species; these species need water rich in dissolved oxygen this group includes Sliders (Trachemys sp.), Cooters (Pseudemys sp.), Map turtles (Graptemys sp.), Soft-shell turtles (Apalone sp.), and Musk turtles (Sternotherus sp.) to give these guys the best chance make sure the pond is well oxygenated.
2. Enclosed pond dwellers; these guys tend to be found in still water, that gets completely frozen over in winter, and include Painted turtles (Chrysemys sp.), Snappers (Chelydra sp.) and Spotted turtles (Clemmys sp.). These turtles will seek out the coldest spots in the pond.

Designing Your Pond

After hibernation turtles will have used all their oxygen supplies and will be too heavy to swim up to the surface. Unless they can walk up to the surface they may drown once the water temperatures rise. Make sure your pond has sloped sides and plenty of ways for a turtle to walk to the surface in the spring.

Keepers with waterfall outflows, and higher flow rate pumps seem to have more success with overwintering their turtles, so try and incorporate this into your set up, and plan to run it over winter.

The pond shouldn’t be too deep, a maximum of two feet deep will mean that you won’t get layers forming with no oxygen. At this depth oxygenating plants can get sunlight and carry on producing oxygen even under ice. Although turtles can and will eat plants species such as elodea will survive being snacked on and produce oxygen which will help the turtles.

Escape proofing your enclosure is vital, turtles are amazing climbers, a quick search of online videos and you will see how amazing they actually are. Wooden fencing is harder to climb than chain link fencing, and it’s worth building in an overhang.

Females can lay eggs even if there is no male around, so make sure there is an area that she can dig down and lay eggs. Some turtles will choose to hibernate in the leaf litter and soil so allow them this option.

Pick a spot for a basking area where it gets the most sunlight for basking, make it a sheltered spot to allow them to bask in as much warmth as possible.

Choosing your turtle

There are two things that will influence your choice of turtle, availability and suitability. It should be the later rather than the former that influences your choice in turtle.

Trachemys sp. (Sliders); Yellow Bellied, Red Eared and other Pond Sliders are amongst the most commonly available turtles, but they are a mixed bunch when it comes to being suitable for overwintering outside. Since their natural range includes southerly and northerly populations, there is always a chance that the turtle you get is from the southerly population and not able to hibernate properly. Try and get turtles that have been wintered outside before as there is no way of knowing where their original genetics have come from.

Pseudemys sp. (Cooters and River Cooters); keepers have reported more success with this species, but they grow much larger and the larger the turtle the more dissolved oxygen it needs in the water to keep it going over winter.

Graptemys (Maps); again these seem to have relatively good success in coming through hibernation, especially the False Map (Gramptemys pseudogeographica), a smaller sized turtle over all they are commonly available, and it may be practical to bring them indoors for the winter.

The enclosed pond dwelling species listed above, excluding the snappers, seem to be ideal for overwintering outdoors in the UK. But they are less readily available and a lot more expensive if you do find them.

As of August 2016, the red-eared slider (Trachemys scripta elgans), the yellow-bellied slider (Trachemys scripta scripta) and the Cumberland slider (Trachemys scripta troostii) havenow been classed as an invasive species of turtle in the EU, and some important regulations have been introduced which will effect owners of these turtles or anyone trying to breed, sell or rehome them. Please read this following article on thenew EU Regulations on invasive species.

Acclimatising your turtle

Aim to put your turtle out at the height of the summer and make sure their as healthy as possible. It may be worth putting them out for a few times during the day only, although if the pond is large enough there won’t be a temperature drop overnight. Make sure that they have plenty of time out before the winter and get a good diet to build up their energy reserves. If possible keep an eye on them and if you see a lot of movement even in the coldest part of winter it may be worth bringing them in for the rest of the winter.

Thousands of turtles have survived and thrived in the UK after being dumped in waterways, but it is probable that thousands died and only the suitable ones survived. The winter of 2011/2012 and 2013/2014 were bad for keepers, especially those with over stocked ponds. But those with well-designed ponds and healthy turtles got theirs through with little or no problems.