Turtles spend their summers basking in the sun and swimming in ponds, but what do turtles do in the winter? They can’t exactly build a snowman!
Turtles are cold-blooded, also known as ectothermic, which means they rely on external sources to regulate their body temperature. That makes them especially vulnerable to freezing temperatures. So, how do they survive the winter months?
The answer involves slowing down their metabolism to a crawl and even absorbing oxygen through their skin. Let’s take a closer look at how turtles manage to survive the winter.
The winter slowdown: Metabolism and torpor
Turtles are ectothermic, or “cold-blooded,” which means they rely on outside sources, such as the sun, to regulate their body temperature. As water temperatures drop, a turtle’s metabolism slows way down. This reduced metabolic rate means they don’t need nearly as much food or oxygen.
To conserve energy, turtles enter a state of torpor, which is a period of decreased physiological activity. It’s not exactly hibernation, but it serves a similar purpose. Turtles become dormant, remaining mostly still at the bottom of ponds, lakes, and other bodies of water.
Breathing underwater: Cloacal respiration and oxygen absorption
Even when they’re in a state of torpor, turtles still need some oxygen to survive. But how do they get it when they’re underwater in cold, sometimes oxygen-poor, water?
The answer is that turtles can absorb oxygen in a few different ways. One of the most fascinating is through a process called cloacal respiration.
The cloaca is an opening that turtles (and other reptiles, amphibians, birds, and fish) use for excretion and reproduction. In the area around the cloaca, there are many blood vessels. Turtles can actually absorb oxygen through that blood-vessel-rich area. As some people say, they “breathe through their butts.”
This method lets turtles pull oxygen right out of the water.
Turtles can also absorb some oxygen through their skin and the lining of their mouths. These methods are especially important when the water is low in oxygen.
Painted turtles and their cold-weather adaptations
Painted turtles are a great example of how turtles can survive even very cold winters. They can live in water as cold as 37 degrees Fahrenheit!
To survive, the painted turtle breaks down something called glycogen, which creates lactic acid. Painted turtles can neutralize the lactic acid with chemicals they get from their own shells. Pretty cool, huh?
Other kinds of turtles, like snapping turtles, also have ways to survive the winter. But painted turtles are especially good at tolerating low oxygen levels, which is important when they’re spending the winter underwater.
Environmental Factors and Winter Habitat
A suitable winter habitat is essential for turtle survival. They need to find the coldest spot in the wetlands that isn’t actually freezing so they don’t run out of oxygen.
If turtles can’t find the right habitat, or if the winter is colder than usual, they may die. How thick the ice gets and how deep the water is also makes a big difference.
Different types of turtles can tolerate different levels of oxygen, which also influences where they choose to spend the winter.
Winter pond care: Helping turtles thrive
If you have turtles in a backyard pond, there are a few things you can do to help them make it through the winter months.
Maintaining oxygen levels
It’s important to make sure turtles and other aquatic life have enough oxygen to survive the winter. Aerators can add oxygen to the pond water, especially if the pond is covered in ice.
Preventing freezing
Pond de-icers can keep small holes open in icy ponds. These holes allow for gas exchange and prevent toxic gases from building up in the water.
Other considerations
When water temperatures are consistently below 55 degrees, stop feeding the fish in your pond. Any uneaten food will decompose and lower the oxygen levels in the pond water.
Wrapping Up
To survive the winter, turtles slow down their metabolism, breathe through their butts, and carefully pick a habitat that will keep them safe until spring. Understanding the amazing biology of turtles is key to protecting them and the places where they live.
Even in the face of cold and challenging conditions, turtles are incredibly resilient. They’ve found remarkable ways to adapt and thrive.