A male is called a boar, and a female is called a sow. There is little sexual dimorphism, so it can be hard to distinguish males and females.
Guinea pigs make several noises, including squeals and whistles. They are easily startled and panic easily. They can be rather messy, and their cages require frequent cleaning.
On a dietary level, Guinea pigs differ from most other pet rodents because their bodies cannot make their own Vitamin C. It is critical that they eat a diet specifically designed for Guinea pigs. Otherwise, they will develop diseases including scurvy.
If you've ever heard anyone say that you shouldn't house Guinea pigs and rabbits together, this is why. Guinea pigs are susceptible to Bordetella (part of the complex of pathogens that causes "kennel cough" in dogs). They may serve as carriers or show signs of pneumonia. Other carriers include rats, rabbits, dogs, cats, swine, and primates.
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