Mammals are vertebrate animals that are endothermic, have hair on their bodies, and produce milk to feed their babies. Many mammals give birth to live young that are small and helpless. Producing milk to feed them allows them to develop more slowly and spend time with the adults as they grow up, learning the skills they need to survive. Regulating their own body temperature and having hair of various thicknesses for protection has also allowed mammals to live in almost every habitat on Earth.
Like other rodents, the guinea pig has long incisors, which grow constantly to compensate for wear. Only the front surfaces bear enamel and, since the inner surfaces of the incisors wear down more quickly, they remain bevel-edged.