The head and body length of a spider monkey is 15 to 25 inches and the tail is around 20 to 35 inches. Their weight ranges from 12 to16 lbs while the hair is generally coarse and stringy. Colors range from golden, red, buff to brown or black with hands and feet generally black. The hands are like hooks with long narrow palms, long curved fingers and no thumb. Their limbs and tail are exceptionally long in relation to body. The tail is prehensile while the head is small. Their muzzle is very prominent (but brain capacity, 107 grams, is twice that of same-sized howler monkeys).
These monkeys range from the tropical forests of southern Mexico to the south in Bolivia and the Matto Grosso in Brazil. Elevation areas range anywhere from sea level to higher ground.
They associate in groups of 2 to 8 individuals; groups are units of a main band which usually consists of 15 to 25 animals. Each band inhabits an area of forest centering around food supplies and sleeping trees. When approached in the wild, spider monkeys usually scatter. But thier most frequently heard call resembles whinnying of a horse which is probably a “greeting” call. Female groups with offspring are the most cohesive units in an otherwise loosely nit group. High ranking spider monkeys groom more than they are groomed.
Only gibbons exceed spider monkeys in agility in the trees. Normal movement through trees is along upper surfaces of limbs with their tail arched over the back as a fifth limb. They have the ability to grasp objects with single hand, foot, or tail alone. They are basically quadrupedal but are capable of rapid progression with legs extended by swinging below branches using arms and tail. They rarely descend to the ground but are capable of bipedalism on the ground with tail held in a curve parallel to the back.
DIET: The diet consists of 72% fruits, 22% young leaves (carefully selected) and 6% flowers. Spider monkeys are characterized for their rapid passage of food through the digestive system (about 4 hours).
BREEDING & REPRODUCTION
A females menstrual cycle is 24-27 days and the gestation period around 139 days. Young are carried on the mother’s abdomen for about four months, then carried on the back. Females wait about 3 years before mating again and their young will grow to adulthood in 4 to 5 years. Infants use their prehensile tail to hold onto their mother’s tail. Infants are black for six months, during which time it is entirely dependent upon its mother. Adult coloration is completely acquired by 10 months. The life expectancy of this species is 25 years.