If you live in the U.S., chances are you’re experiencing a heat wave like what we saw in Utah last week. With high temperatures across the nation, it’s high time for a reminder about the potential danger heat poses to our cavy friends.
Cavies are indigenous to the Andes mountains in South America and are not equipped to tolerate a wide range of temperatures. Guinea pigs evolved in mountain top prairies and grasslands near the equator, absent the seasonal changes we see in most of North America. They adapted to live in a stable environment with temperatures that rarely drifted outside 65 – 75 degrees, with relative humidity below 50 percent. Consequently, cavies never really developed an effective cooling system that would allow their species to thrive in higher temperatures.
Because guinea pigs cannot cool themselves, heat is a seriously limiting factor for the species. Problems can arise when temperatures exceed 80 degrees — males are known to become sterile, and pregnant females can develop toxemia (an infection that develops in the uterus after the death of the fetuses) within three hours if deprived adequate water. Temperatures above 90 degrees can prove fatal.
Heat stroke is almost always fatal in cavies. Warning signs include excess drooling, extreme lethargy, and poor body condition (the cavy’s muscles will relax and, as described by the ACBA husbandry article, assume the characteristics of wilted lettuce). If your cavy develops these symptoms, a warm bath should be administered immediately. This may help cool the cavy sufficiently to save its life, though, again, heat stroke is almost always fatal. Never use cold water to attempt to rapidly cool a heat-distressed cavy. The sudden change in temperature may cause the animal to go into shock. Syringe-feeding a small portion of room-temperature water, or even Gatorade, may also prove helpful.
On the other hand, guinea pigs cope relatively well with cold temperatures. Cool weather between 40 – 50 degrees does not seem to pose much of an issue — if they do get a bit chilly, cavies will huddle together to keep warm, and generally do just fine. Brief exposure to more extreme temperatures also does not seem to be an issue; however, prolonged exposure to cold can cause cavies to develop respiratory infections.
An interesting observation I have made: of all the common breeds of cavy in the U.S., the Peruvian seems by far the most susceptible to heat stroke. Cavies, like many related species, do have one limited method of cooling — they disperse heat by circulating extra blood through their ears. If you pay close attention, you can actually see blood flow in the ears increase during hot weather. This is, in my unscientific opinion, possibly the reason why all guinea pigs have bald spots on their necks, just behind the ears. Hair over the ears would prevent even this limited means of cooling from functioning effectively. The Peruvian’s thick frontal completely covers the head and ears at maturity. If you have Peruvians you are showing, keep a close eye on them during hot weather, especially if you are travelling, and consider pinning back the frontal with some bobby pins. If you’re not showing, trim the frontal back away from the ears.