It can be difficult to determine whether a sick, sleeping or brumating turtle is alive or dead -- and that's an odd circumstance to have with a pet. In some cases, cool temperatures and illness can make a turtle so lethargic and unresponsive that you might mistake him for dead. Let your vet take a look before you call the coroner. If your pet's alive but ailing, the vet may be able to save his life.
Novice turtle owners often struggle to provide proper conditions for brumation, so most reptile experts advise keeping turtles active year-round, unless you're attempting to breed them. Otherwise, they cease feeding in the fall. Brumating turtles often appear dead, as their bodily functions slow to a snail's pace.
It is not advisable to disturb brumating turtles, who generally bury themselves under substrate and snooze throughout the winter. In most cases, the wise decision is to leave an apparently brumating turtle alone unless he begins to emit an odor. However, if you must check on your turtle, place him where he'll warm up slowly, over the course of 24 hours or more. If the turtle is not dead, you will likely observe signs of life as he warms.
Stimulate the Turtle
Perhaps the simplest way to determine whether a turtle is dead or is alive and sleeping is to gently poke or prod him. Most living turtles will move, close their shells or hiss in response to being disturbed. You can also pull a turtle's legs or tail very gently; living turtles typically respond to this by withdrawing into their shells or wiggling their legs to free them.
Another technique is to apply gentle pressure to a turtle’s tail and cloacal region with a gloved finger. Most living turtles will react to this type of pressure by trying to escape. Some may extend their heads when they feel this type of contact. If nothing else elicits movement or signs of life, place your turtle on his back. Most turtles respond to this by frantically trying to right themselves, flailing their legs and extending their necks.
Like all animals, dead turtles begin to decompose rather rapidly. As microorganisms begin feeding on a dead turtle’s tissues, they begin producing foul-smelling gases. In many cases, odor is the first clue of a turtle's demise. It can take a day or more for a dead turtle to begin to smell, and in cool temperatures -- such as those maintained during brumation -- it may take longer.
These gases can make a dead turtle buoyant. Accordingly, you can place a suspected dead turtle in a shallow tank of water to see if it floats or sinks. This test is not 100 percent conclusive, as the microorganisms living in a dead, cold turtle may not have produced enough gases to keep the turtle afloat by the time you do the water test. Additionally, while living turtles usually sink when placed in a tank of water, they can obviously float if they wish to. Use great care when trying this method with terrestrial turtles or tortoises, who often swim poorly and may experience anxiety from being placed in water.
While turtles can hold their breath for very long periods, and they typically have much slower breathing rates than humans and other endothermic creatures, they must breathe eventually.
You can watch the area between your turtle’s rear legs and his tail, or between his front legs and neck, for subtle pumping movements caused by the movement of the lungs.
If you can't discern movement, place a feather in front of the turtle's nostrils and watch for signs that the feather is moving with the turtle’s breathing. Be sure to watch the turtle for an extended period of time -- at least 10 minutes -- before determining that he is not breathing.
If you suspect your turtle is dead or dying, consult a reptile-oriented veterinarian. By virtue of his experience and training, such a veterinarian is better able to determine the state of your turtle’s health. A veterinarian may prescribe medications or treatment regimens to help improve your turtle’s health, if he is still alive.