The ruffed lemur, a medium-sized primate, weighs 6 to 7 pounds. These prosimians (not true monkeys) have long, silky fur that is black and white in two subspecies and red and black in the third. Lemurs are highly developed for life in the trees. Their long tails act as counterbalances while they move through the trees. Lemurs have a variety of calls, the most characteristic being an intense roar of alarm and a powerful, plaintive call for territorial expression.