Rabbit heatstroke: the cool-down order and the 72 hours after

Quick answer

Heatstroke in a rabbit is won or lost in the first fifteen minutes, so the kit and the plan have to exist before the hot day arrives.

A rabbit cannot sweat and cannot pant effectively. It sheds heat mainly by pushing blood through the large vessels of its ears, and once the surrounding air is as warm as the rabbit, that system stops working.

Cool the ears, not the body. Move the rabbit somewhere cool, wet the ears with cool water, provide airflow and a cold surface to lie on, and get to a vet. Never plunge a rabbit into cold water, and never treat a hot rabbit as a case you can finish at home.

• Panting in a rabbit is not an early sign. It is a late one, and it means act now.
• Wet the ears and mist the coat lightly. Do not soak or immerse the body.
• Never use iced water. Extreme cold shuts down the skin circulation, which traps heat inside and can cause shock.
• Before you conclude it is heat, look under the tail. In summer, a collapsed rabbit may have flystrike, and that is a different emergency with the same appearance.
• A rabbit that looks recovered by the evening still needs veterinary care. Most of the deaths come afterwards, from gut shutdown and organ damage.

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Cool the ears. Do not immerse the rabbit.

Cold water over the whole body causes the blood vessels in the skin to clamp shut. That reduces the amount of blood reaching the surface, so heat stops leaving the core just when it needs to leave fastest, and the sudden temperature shift can push a compromised rabbit into shock.

Use cool, not cold, water. Wet the ears thoroughly and repeatedly, damp the feet, and mist the fur lightly. Sit the rabbit on ceramic tile or a cool floor, move air across it with a fan aimed past it rather than at it, and go to a vet.

A rabbit that is flat, panting, unresponsive or having tremors is a critical patient. Begin cooling and travel at the same time, not one after the other.
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Decide in 60 seconds

Why a rabbit overheats so easily

Heat leaves an animal by four routes: radiation from the skin, conduction into cooler surfaces, convection into moving air, and evaporation from wet surfaces such as skin or airways.

Rabbits have almost nothing available on the evaporation side. They do not sweat meaningfully, and although they can increase their breathing rate, they are built to breathe through the nose and cannot move air the way a panting dog does.

That leaves radiation, conduction and convection, and the ear is the organ built for it. Rabbit ears carry large superficial blood vessels and a big surface area relative to the body. When a rabbit is hot, it increases blood flow to the ears and dumps heat from them into the surrounding air.

This works only while the surrounding air is cooler than the rabbit. On a still, hot day, in a hutch in the sun or in a poorly ventilated shed, the air reaches the rabbit's own temperature and the radiator stops functioning. The rabbit then has no remaining route out.

Humidity makes everything worse, because what little evaporative loss there is from the airways depends on the air being able to accept more moisture.

This is also why a fan matters. Moving air across the ears restores convection, and it is one of the few interventions that works without touching the rabbit.

Early, established and late

Early. The rabbit seeks the coolest place it can find and stretches out flat, often on tile, concrete or bare earth, with the legs extended behind. It moves less. It may stop grooming. Ears feel hot and look flushed with visible vessels. Eating slows.

Established. Breathing becomes fast and shallow. The nose is wet, and there may be drooling or wetness around the mouth. The rabbit is reluctant to move at all, and may not respond normally to you or to food. Some rabbits become restless and shift constantly before going quiet.

Late. Open-mouth breathing, which in a rabbit is close to the end of the road. Gums pale, grey or blue. Tremors, incoordination, seizures. Collapse and unresponsiveness. Blood-tinged fluid from the nose or mouth in the worst cases.

Because rabbits conceal illness, the gap between "lying flat, seems fine" and "collapsed" can be very short. Treat the flat, quiet rabbit on a hot day as an emergency in progress rather than as a rabbit relaxing.

The cool-down order

One. Move it out of the heat. Indoors, a tiled room, a cool floor, the shaded side of the house. Do this before anything else, because everything else fails if the rabbit is still gaining heat.

Two. Wet the ears. Cool water on a cloth, or poured gently over the ears, repeated as they warm again. This is the highest-yield action available to you and it targets exactly the organ the rabbit uses.

Three. Airflow. A fan set to move air past the rabbit, not blasting directly into its face. Air movement across damp ears removes far more heat than either alone.

Four. Cool surfaces. A ceramic or slate tile, a frozen water bottle wrapped in a towel placed beside the rabbit so it can choose to lean against it, or a cool damp towel underneath rather than over the rabbit.

Five. Damp the feet and mist the coat lightly. The feet have exposed skin. Light misting helps a little. Soaking does not, and a saturated coat becomes an insulating blanket.

Six. Offer water, do not force it. Put water where the rabbit can reach it without moving far. Do not syringe water into the mouth of a rabbit that is drowsy or breathing hard, because it will be inhaled.

Seven. Travel. Phone the vet while you cool. Take the rabbit in a carrier with a cool damp towel and a wrapped frozen bottle, with the car air conditioning on before the rabbit goes in. Do not leave a rabbit in a parked car for any length of time at all.

Stop active cooling when the rabbit becomes responsive and its ears are no longer hot. Cooling past that point risks the opposite problem in a small animal.

Before you assume it is heat, check the rear

In warm weather, a rabbit found collapsed in a hutch has two common explanations, and heat is only one of them.

Flystrike happens when flies lay eggs on a rabbit's damp or soiled rear, and the maggots that hatch burrow into the skin. It develops in hours, not days. The rabbit becomes quiet, then collapses, and the shock and toxin release kill it.

Any collapsed rabbit in fly season should have its tail area, groin and underside examined immediately. Look for wetness, a smell, brown staining, and small pale maggots in the fur or in a wound.

If you find them, this changes the destination but not the urgency. Do not attempt to bathe the rabbit or drown the maggots. Pick off what you can see, keep the rabbit warm rather than cold, and go straight to a vet.

The other look-alikes worth knowing about are gut stasis, which produces a hunched, quiet rabbit that grinds its teeth and passes no droppings, and, in unvaccinated rabbits in some regions, myxomatosis, which causes swollen eyelids, lips and genitals in the days before collapse.

The 72 hours after are the dangerous part

The measure of recovery is not that the rabbit looks better. It is that the rabbit is eating and producing normal droppings.

Heat injures the lining of the gut, and it interrupts the constant motility a rabbit's digestive system depends on. It can also damage the kidneys and liver, and disturb blood clotting, and none of that is visible on the day.

The rabbit that survives the afternoon can therefore die three days later of gut stasis, which is why the veterinary visit is not optional even when the rabbit seems to have recovered.

Watch three things and write them down.

Eating. Not merely interest in food, but actual chewing and swallowing of hay. Hay intake, not pellets or treats, is the number that matters.

Droppings. Count them, and note their size. Fewer, smaller, or drier droppings than normal is the earliest reliable sign of stasis. None at all for a stretch of hours is an emergency.

Demeanour. A hunched posture, pressing the abdomen to the floor, teeth grinding, and reluctance to move are pain signals.

Expect the vet to consider fluids, pain relief and gut motility support, and follow through with any assist feeding they prescribe. A rabbit that will not eat cannot be left to come round in its own time, because prolonged anorexia in this species causes liver damage of its own.

Who is at highest risk

Rabbits living outdoors in a hutch or shed, especially where the sun moves onto a position that was shaded in the morning.

Dense-coated and long-coated breeds, and any rabbit part-way through a moult with dead coat trapped in the fur.

Breeds with small ears, and lop breeds whose ears are folded and hang rather than standing free in moving air.

Overweight rabbits, and rabbits with large dewlaps, both of which carry insulation and reduce the ability to stretch out.

Elderly and arthritic rabbits, and any rabbit that cannot move easily. A rabbit that cannot walk to the shade does not get the shade.

Rabbits with existing dental, respiratory or heart disease, and any rabbit recovering from illness.

Rabbits in transport. A carrier in a car, a waiting room or a garden shed heats far faster than the space around it.

Rabbits with soiled rears, because heat and flies arrive together.

Setting up before the heat

Carrier, towels, water and a grooming comb kept together. In hot weather the comb matters as much as the rest, because trapped dead coat is insulation the rabbit cannot remove.

What the vet will ask

How long the rabbit was in the heat, and where it was found.

What its ears felt like and what its breathing looked like when you found it.

What cooling you used, and for how long.

When it last ate, and when you last saw a normal dropping.

Whether it is vaccinated, and against what, since summer collapse in an unvaccinated rabbit raises other possibilities.

Whether it lives with another rabbit, and whether that one is affected too.

Whether the rear end was checked, and what you found.

Any existing conditions, medications, dental history and recent weight.

Expect the vet to take a body temperature, give fluids, and want to keep the rabbit for monitoring. Expect a discussion about the following days rather than a discharge with nothing to do.

What never to do

Never immerse a rabbit in water, and never use iced water, ice packs directly against the skin, or a cold bath.

Never wrap a hot rabbit in a wet towel. Covering it traps heat rather than releasing it. Put the damp towel underneath, not over.

Never leave a rabbit in a car, a conservatory, a greenhouse or a shed in warm weather, even briefly, and even with a window open.

Never force water or food into the mouth of a drowsy, collapsed or heavily breathing rabbit.

Never assume recovery because the rabbit perked up. The gut has not recovered on the same timescale as the demeanour.

Never treat a summer collapse without looking under the tail first.

Never rely on a hutch cover or a parasol that was shading the hutch at nine in the morning. The sun moves and the rabbit cannot.

Never give human medications, including anything for fever.

When to get help

Go immediately for panting or open-mouth breathing, collapse, tremors, seizures, pale or blue gums, or a rabbit that cannot be roused. Cool the ears while you travel rather than before you leave.

Go immediately, to the nearest vet, for any maggots found at the rear, whatever else is happening.

Go the same day for a rabbit that was found hot and flat and then recovered, for one that is breathing faster than usual after cooling, and for any rabbit that has not eaten since the heat.

Go the same day at any point in the following three days if droppings become fewer, smaller or absent, if the rabbit hunches and grinds its teeth, or if hay intake falls.

Phone ahead, describe the breathing and the ears, and ask whether they want you to keep cooling on the way. Take a wrapped frozen bottle and a damp towel in the carrier, and have the car cool before the rabbit goes into it.