Guinea pigs are comfortable only in the narrow temperature range from 65°F to 75°F (18°C to 23°C). They also prefer a low relative humidity (below 50%). When exposed to temperatures above 85°F (29°C), they may develop heat stroke. Thus, special care needs to be exercised when transporting these animals during very cold or very hot days. They do not thrive in drafty locations and should not be constantly exposed to direct sunlight.
Because of their small size, guinea pigs often suffer injuries when outside their cages. They can be seriously injured if they are stepped on or fall off a table. Like many other rodents, guinea pigs are attracted to anything that looks interesting to chew. Electrical cords are common hazards for these animals. Other pets, such as dogs, cats, and ferrets, may easily injure guinea pigs. In addition, many common houseplants are toxic for guinea pigs. Whenever your guinea pig is outside its cage, it should be very carefully monitored to keep it safe.
Unlike hamsters and rats, guinea pigs are mostly diurnal—that is, they are usually awake during the day and sleep at night. This makes them a good choice as pets because they will be active during the day when you can observe them and handle them without disturbing their rest.
Keeping more than one guinea pig provides companionship for your pet. Keeping only guinea pigs of the same sex prevents them from mating. If you plan to keep male guinea pigs together, they should either be neutered or be introduced to one another before they are finished weaning from their mothers. This will help prevent fighting. Guinea pigs may panic or become stressed if they come into contact with other pets, so keep them separate from dogs, cats, or other animals. This will also help prevent the spread of infectious diseases.
Guinea pigs have unusual sensitivities to many commonly used antibiotics when given orally, by injection, or rubbed on in creams. Many of the most widely used antibiotics can be toxic for your guinea pig. Do not use antibiotics or products containing antibiotics on your guinea pig without the guidance of a veterinarian.