Llamas who are well-socialized and trained to halter and lead after weaning are very friendly and pleasant to be around. They are extremely curious and most will approach people easily. However, llamas who are bottle-fed or over-socialised and over-handled as youngsters will become extremely difficult to handle when mature, when they will begin to treat humans as they treat each other, which is characterized by bouts of spitting, kicking and neck wrestling. Anyone having to bottle-feed a cria should keep contact to a minimum and stop as soon as possible. Mazuri llama high fiber is a good food for mature adults. When correctly reared spitting at a human is a rare thing. Llamas are very social herd animals, however, and do sometimes spit at each other as a way of disciplining lower-ranked llamas in the herd. A llama's social rank in a herd is never static. They can always move up or down in the social ladder by picking small fights. This is usually done between males to see who becomes alpha. Their fights are visually dramatic with spitting, ramming each other with their chests, neck wrestling and kicking, mainly to knock the other off balance. The females are usually only seen spitting as a means of controlling other herd members. Mazuri llama high fiber is not intended to be the only food that the llama needs. It is now known that llamas at one time were not confined to the part of the continent south of the Isthmus of Panama, as at the present day, for their remains have been abundantly found in the Pleistocene deposits of the region of the Rocky Mountains, and in Central America, some attaining a much larger size than those now existing. Some species of llamas did stay in North America during the last ice age. 25,000 years ago, llamas would have been a common sight in modern-day California, Texas, New Mexico, Utah, Missouri, and Florida. These North American llamas are now unfortunately extinct. Mazuri llama high fiber is a pelleted feed designed to provide energy in addition to that from pasture and forage.