Understanding how the rabbit cools itself helps us to provide the most comfortable environment for our rabbit in hot, humid weather and helps to prevent heat stress. Aged, overweight and pregnant rabbits are most susceptible to heat prostration.
Rabbit stretched out and panting
Moisture around face and/or drooling
Bloody discharge from mouth/nose
Enlarged blood vessels in ears and mouth turning blue
Eighty percent of heat dissipation in rabbits occurs through the evaporation of moisture during respiration (breathing). Fans help this cooling process by speeding evaporation. Cooling also occurs through nasal mucosa (by air passing over mucous membranes). The ears are also important for cooling as the blood moves to the farthest (coolest) points away from the body core. The rabbit will also stretch its body out as far as possible to cool through radiation/convection. Rabbits do not have many functional sweat glands; so only lose a small amount of moisture through the skin due to perspiration. The rabbit’s fur further inhibits the process of the rabbit being able to cool itself by evaporation of moisture from the skin.
Temperatures approaching 90 degrees Fahrenheit can be dangerous to rabbits, and temperatures in the 80’s can also be a concern if the humidity is high. Rabbits should never be placed in full sun.
If you have a rabbit showing signs of heat stress, move it too a cool area and place a fan nearby to create a gentle breeze, then contact your vet immediately. In advanced cases, your vet may recommend cooling the bun with tepid (not cold) water, as well as the administration of electrolytes.
The best way to assure a rabbit does not suffer from heat stress is to make him or her a permanent indoor member of the family. Housing your bun in your air-conditioned home will keep him safe from heat stress and allow you to fully enjoy these very social creatures.
Orlando Diaz-Figueroa, DVM, MS, Dipl. ABVP (Avian Specialty)