Heat stoke can kill rabbits. Overheating is a major killer of pet rabbits left exposed to the elements. Rabbits do not pant like dogs. Those who are living in the wild are able to go underground, but the only way bunnies can dissipate heat is from the blood vessels in their ears. If the temperature goes higher than 80 degrees Farenheit (26 Celcius) then heat stroke can be caused. So if you are experiencing hot weather it is important to provide a space where your bunny can stay cool and comfy. Here are some tips:
Fill plastic water bottles with tap water, freeze them (remember that water expands when frozen, so do not over-fill to avoid cracking), and put them in the cage.
Spray rabbit ear tips with water, which provides cooling as it evaporates.
Keep the sun off the cage by pulling blinds and keep the room cool by not burning any incandescent light bulbs.
Fill a bowl with ice and water and place it in front of an oscillating fan.
These tips are courtesy of 3 Bunnies Rabbit Rescue in East Hartford, CT, who say:
If your bunny becomes listless and unresponsive, get him to a vet immediately!
Would you be interested in building a cheap air conditioner for your rabbit? The same web page where we found the hot weather cooling tips includes instructions for building a battery-powered air conditioning bunny hidey box.
Here is a link to the 3 Bunnies Rabbit Rescue page with details on how to build a rabbit air-con box, using inexpensive materials most of which you may already have around the house: http://3bunnies.org/bunnyAC.htm
Update: Here is a link to a newer post on keeping rabbits cool even if you don’t have electricity.