Guinea pig varieties found in pet stores are the English shorthair (also known as the American), which have a short, smooth coat, and the Abyssinian, whose coat is ruffled with cowlicks, or rosettes. Also popular among breeders are the Peruvian and the Sheltie (or Silkie), both straight longhair breeds, and the Texel, a curly longhair. Grooming of guinea pigs is primarily accomplished using combs or brushes. Shorthair breeds are typically brushed weekly, while longhair breeds may require daily grooming. Cavy clubs and associations dedicated to the showing and breeding of guinea pigs have been established worldwide. The American Cavy Breeders Association, an
Rock cavy pile, she indirectly chooses the builder as her mate. Females weigh 700-800 g and give birth to one or two young only, but several litters per year are common. The gestation period averages 75 days. The newborn cavies weigh 90 g. The placenta for a rock cavy is similar to other hystricomorph rodents. They have several lobes that are lined with blood vessels and undergo a counter-current blood flow. There are blood vessels running from the mother along the placenta and then vessels running from the fetus back over the mothers vessels. This allows for a better flow of oxygen