Many turtles can survive the winter in your Pennsylvania pond. Just like koi and goldfish enter a state called torpor, turtles enter a state similar to hibernation, called brumation. During brumation they can stay under water for months at at time.
During the warm summer months, they surface frequently to breathe through their mouths. If they are buried in the mud in the bottom of the pond for the winter -how do they breathe? Well, as one researcher so eloquently put it, they breathe through their butts.
Yep. Nature is amazingly weird. Turtles have some incredible biological tricks that help them survive extreme conditions
At a Glance: How Pond Turtles Survive the Winter
Aquatic turtles usually spend winter buried in mud on the bottom of the pond where water stays cold but above freezing.
As temps drop, their metabolism slows dramatically and they enter brumation, so they need very little food and oxygen.
They can absorb oxygen through the water around them (through the lining of their mouth, throat and cloaca) which allows them to survive under ice.
Winter Slow-down
Let’s go back to elementary school science for a moment.
Turtles are ectotherms – a fancy word for cold-blooded. This means their body temperatures match their environment. If the water is cold, the turtle’s internal temperature is too. This biology is different from that of warm-blooded animals, which need to constantly generate body heat.
Being cold-blooded in winter sounds rough, but it’s actually what helps turtles survive. As their body temperature lowers, so does their metabolism. And a low metabolism means less need for food and oxygen.
Most aquatic freshwater turtle species survive the winter by submerging themselves in the muddy pond bottom. In an ecosytem pond designed with turtles in mind, the bottom will have areas with a deep soil pocket. Although the pond surface may freeze, the temperatures remain above freezing in the bottom of the pond.
Turtles might occasionally swim to the surface, but they’ll generally stick to the mud until spring.
Still Breathing
How can turtles stay underwater so long? It’s all thanks to … butt breathing.
Turtles have lungs and require oxygen to breathe. In the winter, though, their oxygen needs drop considerably. They absorb the little bit they still need from the water through a special area around their cloaca, which is packed with blood vessels.
The cloaca is the all-purpose final stop at the end of the turtle’s digestive track. (Other reptiles, as well as birds and fish, have similar setups.) Because this area is so rich in blood vessels, the turtle can use it to take in oxygen from the surrounding water in winter and doesn’t need to use its lungs.
The scientific term for this process is cloacal respiration – and it only works in winter. In warmer weather, turtles can actually drown if they stay underwater too long because they need a lot more oxygen to survive.
What kind of Aquatic Turtles can you typically find in Pennsylvania Ponds?
Eastern Painted Turtle Chrysemys picta picta – 4–10 in
Smooth dark shell with red & yellow edges. Loves sunbathing on logs & rocks.Red-eared Slider Trachemys scripta elegans – 5–12 in
Green shell with red streaks near eyes. Loves sunbathing on logs & rocks.- Eastern Musk Turtle Sternotherus odoratus– 3–5 in
Small, dark shell, musky odor if threatened. Hides under logs & eats insects/small fish. Snapping Turtle Chelydra serpentina– 8–20 in
Rugged shell, long tail, strong jaws. Bottom dweller & ambush predator.
What about Box Turtles?
The Eastern Box Turtle (Terrapene carolina carolinacan) grow to about 4–7 in. It’s shell is distinctly dome-shaped shell with yellow/orange spots. Although it may visit pond edges, it is mostly terrestrial, spending it’s life slowly walking around woodlands. The box turtle Hibernates in soil (not underwater).
Let’s get down and dirty …
Soil type and preparation are important things to consider when creating a habitat for overwintering turtles—especially in semi-natural outdoor Splash ecosystem ponds, where turtles burrow into the substrate to brumate (a reptile form of hibernation) and avoid freezing temperatures.
We want a soft, fine, oxygenated mud bottom. The soft mud or silty clay we used is ideal because it’s easy to dig into and allows good oxygen diffusion. Your aeration system will keep the water well oxygenated, help release CO₂, and keep your turtles happy and healthy all winter long. Even during brumation, they are still breathing!
Hard-Packed Clay – You may have read that “clay” is not ideal. That’s very true for ponds with a compacted clay bottom, where heavy construction equipment has rolled and packed the soil to create a watertight seal. In that case, the soil becomes so dense that turtles can’t dig into it.
Organic Muck – Another issue we’ve seen involves soils that are too rich in organic matter (muck). It can get too anoxic/anaerobic with very little oxygen as the organic material decomposes. When organic material decomposes, bacteria and microorganisms break it down and use up oxygen that would otherwise be available for fish, turtles, and other aquatic life. So — the more decaying organic matter (like leaves, dead plants, or algae), the lower the oxygen levels in the water. Such conditions are harmful to aquatic life, especially burrowing turtles.
Remember, your turtles still need oxygen during brumation,
Painted Turtles: The Masters of Cold Weather
Painted turtles – one of the most widespread turtle species in North America- are especially adept at handling the cold.
Adult painted turtles can survive in water as cold as 37 degrees Fahrenheit without food or oxygen for up to 100 days. These conditions would kill most vertebrates in three or four minutes.
Many turtles, however, can survive in extremely low oxygen conditions because of their ability to change their blood chemistry. And painted turtles can survive even longer than most.
While hibernating mammals break down fat stores to survive the lack of food in winter, turtles break down a blood sugar called glycogen. This process creates a build-up of lactic acid in the turtle’s body. Lactic acid is the stuff that causes muscle soreness in humans after we work out, but for turtles, it can turn deadly.
Some turtles neutralize the acid by borrowing chemicals from their shells and skeletons – kind of like a natural Tums. Painted turtles are the undisputed masters of this skill and can survive longer than other turtles in low- to no-oxygen environments.
Remember: the ability to survive extreme oxygen depletion is unique to painted turtles. Most other pond critters – including your pond fish – need good gas exchange in order to survive the winter.
Tips for a Healthy Winter Pond
Ecosystem Ponds are easy to care for and beautiful to look at any time of year.
Here are some tips for keeping everything running smoothly in the cold months:
Do I need to shut down the whole pond in winter?
Whether or not you shut down your pond in winter is up to you.
If you like hearing your waterfalls year-round, you can keep them running. The water runs through your pipes fast enough to prevent the plumbing from freezing.
For the most peace of mind, however, we recommend winterizing your pond. With the pump off, you don’t have to worry as much about water loss or other issues.
Check out our Winterization Guide for step-by-step instructions.
Regardless of whether you winterize the entire pond, you still need to turn off your autodoser if you have one and move it to a frost-free location.
Stop feeding fish
Your fish enter a semi-dormant state called torpor during cold weather. They don’t need to eat while in this state, so any food you give them will either sit in their bellies (bad for the fish) or sit in the bottom of the pond (bad for your water.)
Stop feeding your fish when water temperatures are consistently below 55 degrees. You can ease your fish’s transition into and out of winter with Cold Water Fish Food. Check out our seasonal feeding guide for more information.
Aerate!
Your fish don’t eat in winter, but they do breathe.
Install an aerator to add some much-needed oxygen to your pond and to help keep a hole open in any ice that forms on the surface. An aerator is especially important if you decide to shut off your waterfalls for the season.
If your pond ices over, gently create a hole to let oxygen into the pond and bad gases out. Don’t use blunt force to break the ice; anything too jarring could injure your fish. Instead, place a deicer or pot of hot water on top of the ice to gently melt it. You can also – carefully – cut a hole with a rough-toothed saw.
Speaking of deicers …
Deicers are floating heaters that keep a small hole open in an otherwise iced-over pond. These heaters are small enough that they won’t raise the overall temperature of your pond, and their thermostatic controls ensure they’re only running when they need to be.
Deicers are a great addition to your winter pond care arsenal. With a deicer running, you know a hole will always stay open in your iced-over pond – even if your aerator fails.
Always use a deicer in addition to an aerator – not in place of one. If you can only afford one or the other, an aerator should be your first priority.