Guinea Pigs and Heatstroke


Confession : I always over-fill my muffin tins and then they rise too high and the tops over- brown and stick. I chastise the owners of overweight dogs about their feeding habits as I offer treats from the huge jar of Pupcorn we keep in every exam room. I want my patients to enjoy their visits and stickers just don’t cut it. Right?  At home I poured the cat food into a handy repurposed plastic carry jug (the label read “Orville Redenbacher”) and my daughter Nicole squealed in amazement : “OHHH! The cat food comes in popcorn flavor?!” Bad, bad, bad.


Last week our weather did a belly flop straight into summer. The temperature soared up to 97 degrees Fahrenheit on Thursday, dropping back to 67 by Saturday. The hot flash was over so quickly we barely had time to complain, but…. a guinea pig suffered a heat stroke and nearly died. This little piglet was named Gyarados, after a dragon from the Pokemon Go! game.


He would have been adorable if it wasn’t obvious that the little guy couldn’t stand up straight and was breathing in rapid, shallow breaths. I counted over 100 breaths per minute. His owner explained that they had several piglets maintained in an outdoor shed. With heat lamps and their natural thick coats the Guinea pigs had been toasty and comfortable throughout the rainy winter. (There is no consensus on the need to provide additional heat for a guinea pig acclimated to being outdoors. In the wilds of South America, from which they once hailed, the guinea pig must adapt to temperatures that dip to freezing. I suspect they are well underground in a cozy burrow with the body heat of other piglets to keep them warm. Our guinea pigs are domesticated and may be less hardy. The true domestic guinea pig, cavia porcellus, no longer occurs in the wild.). The change of weather was so sudden that it hadn’t raised any alarm bells. After school the family went out to feed and play with their guinea pigs and found Gyarados passed out. “We thought he was dead!” they cried. They had the presence of mind to start his revival by administering a cold water bath. This method of immersion was frowned upon in the past, many believing that a too rapid decline in body temperature might lead to the heart stopping (cardiac arrest). Medical experts argued that a rapid drop in body temperature would cause shivering, which INCREASES the body core temperature. That said, evidence by experts today suggests that it is best to lower the body temperature of a heat stroke victim within 30 minutes. This is best accomplished by immersion in cold water, bringing it down to near 102 degrees F. Dropping the temperature further and faster with ice might throw the body into another kind of shock. Rapid treatment dramatically reduces the risk of death.


We continued his cooling and administered sub-cutaneous fluids under the skin. Gyarados was treated for shock and started on antibiotics. His skin was bright red from vasodilation, as his blood vessels enlarged to get rid of the extra heat instead of being cooked. Within the first hour his respiratory rate dropped to 60 / minute.


Guinea pigs have been popular pets for thousands of years. During the Inca Empire they were used for food and religious sacrificial ceremonies to the gods. Good natured, they became pets in many South American countries and were popularized throughout Europe after the Spanish conquistadores brought them home.


There is a world famous painting of “The Last Supper” found in the Cathedral Basilica of Cuzco, Peru. Painted by Marcos Zapata in 1753, it replaces the traditional serving of lamb with the native cavy, or guinea pig. This made sense to the native peoples. Paintings served to teach stories during a time that many people did not read.



Once recovered, Gyarados was typical of the average guinea pig. They are personable, making a variety of squeaky noises to express satisfaction or concern. An herbivore, they feed upon loose leaf timothy or grass hay and must be supplemented with vitamin C -enriched guinea pig pellets. Greens and vitamin C-rich vegetables complete their diet. A girl guinea pig is called a sow and a boy guinea pig a boar, just like “real” pigs! We don’t know why they’re named after pigs. They are not related to pigs and are really rodents. A guinea pig Mom can start having babies after 2 months of age. They like living in communes of 5 to 10 piglets. The average guinea pig lives to be 5 or 6 years old.


Christine B. McFadden, DVM


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