Chacoan mara the capybara, and guinea pigs. Chacoan maras are closely related to the other member of the genus "Dolichotis", the Patagonian mara. Maras are the fourth largest rodent in the world after the capybaras, beavers and porcupines . Though the mara may look like a rabbit, the rabbit is not actually a rodent and therefore not as closely related to the mara as one might expect. Chacoan mara The Chacoan mara, Dolichotis salinicola, is a relatively large South American rodent of the cavy family. They are a close relative of the better known Patagonian mara. The Chacoan mara lives in the
Guinea pig role usually played by growth hormone. Additionally, guinea pigs have been identified as model organisms for the study of juvenile diabetes and, because of the frequency of pregnancy toxemia, of pre-eclampsia in human females. Their placental structure is similar to that of humans, and their gestation period can be divided into trimesters that resemble the stages of fetal development in humans. Guinea pig strains used in scientific research are primarily outbred strains. Aside from the common American or English stock, the two main outbred strains in laboratory use are the Hartley and Dunkin-Hartley; these English strains are albino, although pigmented