Hardly a year goes by without the loss of a ferret due to hyperthermia. Hyperthermia occurs when a ferret has too high a body temperature, and it can be a deadly problem in the summer heat. I was particularly impacted by such a possibility last year when my air conditioner gave up the ghost at the beginning of a particularly nasty heat wave. Outdoor temperatures went into the 90s, while indoors, the temps were several degrees higher. The ferrets could not wait for me to repair the unit, so I had to do something immediately to keep them cool.
How Ferrets Keep Cool Naturally
The best way for a ferret to keep its cool is to allow them to use their own innate behaviors to accomplish the task; behaviors forged over millions of years of polecat evolution. Polecats and black-footed ferrets typically live in areas that freeze in winter and swelter in summer. Yet, polecats and ferrets lack significant numbers of sweat glands and other physiological adaptations that heat-tolerant animals seem to possess. So, how do they survive?
Simple — they go underground. Any spelunker can tell you that caves are warm in winter and cool in summer. If deep and protected, the cave interior is the yearly average temperature for the local environment. So, if the summer highs are 110 degrees Fahrenheit and the winter lows are -20 degrees Fahrenheit, the yearly average could be a stable 60 degrees. That makes the cave cozy in winter and cool in summer. A deep burrow acts similar to a cave in that regard. Neither polecats nor black-footed ferrets hibernate, yet they survive harsh, cold winters and sweltering summers quite nicely, snug in a cozy little burrow.
Ferrets also overcome heat by limiting movement as much as possible, abstaining from most play and exploration. Using muscles requires burning calories, which creates heat. Humans sweat to prevent overheating, but ferrets lack appreciable numbers of sweat glands. Hot ferrets tend to limit exercise as much as possible, turning into pathetic furry slugs, slithering across the floor in slow motion.
Hot ferrets frequently cool down by going prone. You have no doubt seen your ferret imitating a speed bump after strenuous play. They go prone on the floor, flattening as much of their body as possible to cool down. This ingenious behavior is a cooling mechanism that works on basic principles of thermodynamics. It is why a tile floor feels cool to your feet even though it is the same comfortable temperature as your room. Your feet are hotter than the floor, so heat flows from your feet into the tile, creating a sensory feeling of coolness. It is why a hot skillet cooks an egg; heat flows from the frying pan into your breakfast. Called “heat conduction,” it is the flow of thermal energy from an object with high temperature to one of lower temperature in the attempt to reach equilibrium. In the wild, a shallow pit in the earth, a shady rock, and muddy wallows are favored for conductive cooling. Water can speed heat loss, so ferrets might soak in a water dish or lounge in urine to cool off; a damp litter box is a favorite spot to lose heat.
Panting is a common method to lower body temperature. Simply put, as cooler-than-body-temperature air crosses the tongue and oral tissues and enters the lungs, heat transfers from blood to the air, helping cool the body. The degree of panting can be used as a rough estimate of heat stress: the more frantic the panting, the more stressed. If panting stops and the ferret is still obviously overheated, it is in serious trouble.
Another method to keep cool is to abstain from food. Food digestion generates heat, and so heat-stressed ferrets usually eat less. Ferrets will drink more water if available. This replaces moisture lost thought panting, but because water is generally cooler than the body core, it directly cools as well. It also increases urination, which also helps to drain heat from the body.
Another behavioral heat adaptation is sleeping. Ferrets will not only decrease their activity levels when heat-stressed, but tend to sleep longer and nap more. Metabolic rates are slower when sleeping and muscles are not working as much, so there is less body heat for the ferret to lose.
How A Ferret’s Environment Can Add To Heat Stress
Ferret housing can contribute to overheating in two ways: it can limit the number of opportunities for a ferret to cool itself, and it can act as a radiator. An elevated cage can hold the ferret up in the air column where it is warmer. A habitat that lacks flat surfaces doesn’t allow conductive cooling. Habitats with sleeping areas filled with heat-holding materials keep a ferret warm in winter, but may contribute to overheating in summer. If in direct sunlight, a habitat can prevent a ferret from escaping to a cooler area. Habitats with heat-holding materials like metal can get very hot, even hot enough to burn feet. All these reasons and more may contribute to a ferret’s heat stress.
Assume if the temperature and conditions are uncomfortable for you, they are just as bad — or worse — for your ferret. Remember, ferrets typically do not show signs of distress until they can no longer cope with the problem. By the time a problem is obvious, it is already serious. You need to recognize the signs of heat stress in order to combat it.
Signs Of Heat Stress In Ferrets
A list of symptoms cannot predict how rapidly a ferret will progress from minor heat stress to heat exhaustion or stroke. Assume you need to take rapid action if a ferret in warm temperatures shows a single symptom. Symptoms of heat stress include:
- Breathing difficulty: air gulping, gasping or other drastic changes in breathing
- Dehydration: sunken eyes, dry tongue, skin “tenting,” concentrated urine
- Drooling: Excessive, thick or stringy drool
- High temperature: body hot to the touch, temperature exceeding 103 degrees Fahrenheit
- Lack of activity or interest: a marked decline in play and exploration
- Level of consciousness: difficulty or inability to wake
- Loss of balance: a stumbling or clumsy gait
- Mental awareness: a confused or trance-like state
- Mucous membranes: reddened or darkened tongue, gums and under eyelids
- Panting: rapid, frantic or excessive breathing
- Paw licking: repeated footpad licking
- Poor appetite: eats little or refuses food
- Prone position: sustained flattened or sprawled position
- Thirst: generally increased, but some might stop drinking under severe stress
- Vomiting and/or diarrhea: a bad sign, get to a vet!
- Weakness: trembling, difficulty of movement or falling
14 Tips To Help Ferrets Beat The Heat
The best cure for heat stress is prevention. While there are no guarantees that the following recommendations will prevent heat stress, they can help lessen the impact. Always consult your veterinarian if you have any doubts or questions about your ferret’s health.
- Bath: A tepid (not cold) bath cools a heat-stressed ferret. If your ferret is frightened by water, use a wet washcloth to cool it down.
- Cooler: Cut an access hole in the side of that old plastic cooler wasting space in your garage and attach about 2 feet of dryer duct tubing to “plug” the hole. Toss in couple of ice packs or frozen water bottles and some light cotton bedding to provide a cool place to sleep.
- Damp soil bath: A pan or small child’s wading pool filled with damp potting soil or sand allows ferrets to cool themselves naturally.
- Electrolytes: Ask your vet the concentration and product you should use for your ferret and when you should use it.
- Fan: Good air circulation is very important; one or two fans dedicated to blowing air through the cage, but not directly on the ferrets, can help.
- Frozen treat: A bowl of ice cubes or frozen chicken broth is a cooling hot-weather treat.
- Heat sink: The best I’ve found is a thick piece of metal plate, roughly a foot square, but heavy ceramic floor tiles work, too. A water-soaked, terra cotta dish or low-sided pan also works. Store a couple of any of these items in your refrigerator and place them in the cage as necessary.
- Ice: Fill plastic soda or milk bottles with water and freeze. Cut down one side of a cardboard box, toss in a couple frozen water bottles, and cover with a layer of towels. You can fill a resealable plastic bag with ice cubes, which always seem to leak, or fill a hot water bottle with ice.
- Misting spray: This is especially good used in conjunction with a fan. Just spray a mist in the air stream and it will drop the air temperature several degrees.
- Shade: Car window reflectors can be attached to the sides of the cage facing a window to prevent the sun from directly heating the cage and its contents.
- Small A/C unit: A small window unit costs about a hundred dollars, but a vet bill for a sick ferret can cost more. Just perch it in a window and push the cage near it, but out of the sun’s rays.
- Splashing pool: About an inch of water in a low-sided pan or child’s plastic wading pool works well if the ferret is open to water play. If not, mist it with a water sprayer.
- Water: Don’t rely on just one water bottle for your ferret to drink from; it can leak or run out. During hot weather, add extra water bottles and even water dishes.
- Wet towel: A wet towel in a plastic tub is a great approximation of a mud wallow. I’ve only had a few ferrets that didn’t enjoy the experience — and they don’t track up the house with mud when they leave.
Heat Emergencies Can Happen Anytime
A sudden power loss, a broken air conditioner, or even a brownout or blackout can rapidly become a serious threat to your ferrets. Knowing what to do — and the rapidity in which you should do it — is a skill every ferret owner needs to possess. If you have a ferret that has become heat stressed and you see symptoms, it is likely the condition is worse than the ferret is letting on. Please, immediately cool it down and call your vet. If a ferret is showing any sign of distress, it is already in danger.
Bob Church is a former photojournalist and current zooarcheologist with degrees in biology (zoology) and anthropology (archaeology). He resides in Missouri with 19 ferrets that keep his chicken blender overheated and his heart overfull.