A teaspoon of guanaco blood contains about 68 million red blood cells four times that of a human. For guanacos to survive in the low oxygen levels found at these high altitudes, their blood is rich in red blood cells. Guanacos are often found at high altitudes, up to 4,000 m (13,000 ft) above sea level, except in Patagonia, where the southerly latitude means ice covers the vegetation at these altitudes. The camels' digestive system is likely to have developed independently of ruminants, which is evidenced by the fact that the forestomachs are equipped with glands. This process is similar to that of ruminants, to which camels are not zoologically related. The food is swallowed with little chewing and first enters the forestomach to be digested finally after rumination. Like all camels, Guanacos are herbivores, grazing on grasses, shrubs, herbs, lichens, fungi, cacti, and flowers. Between 20, 13,200 guanacos were legally hunted in Tierra del Fuego. In Chile, hunting is allowed only in Tierra del Fuego, where the only population not classified as endangered in the country resides. Bolivians use the neck skin of these animals to make shoes, flattening and pounding the skin to be used for the soles. This protects their necks from predator attacks. Guanacos have thick skin on their necks, a trait also found in their domestic counterparts, the llama, and their relatives, the wild vicuña and domesticated alpaca. Other terrestrial mammalian megafauna weighing as much or more than the guanaco include the tapirs, the marsh deer, the white-tailed deer, the spectacled bear, and the jaguar. Guanacos are one of the largest terrestrial mammals native to South America today. The lifespan of a guanaco can be as long as 28 years. Guanacos have grey faces and small, straight ears. Their color varies very little (unlike the domestic llama), ranging from a light brown to dark cinnamon and shading to white underneath. Guanacos stand between 1.0 and 1.3 m (3 ft 3 in and 4 ft 3 in) at the shoulder, body length of 2.1 to 2.2 m (6 ft 11 in to 7 ft 3 in), and weigh 90 to 140 kg (200 to 310 lb).

Dear Patagonia by Jorge González