Bald Uakari - Physiology, Ecology and Geography

Physiology, Ecology and Geography

The bald uakari weighs between 2.75 and 3.45 kg (6.1 and 7.6 lb), with head and body lengths average 45.6 cm (18.0 in) (male) and 44.0 cm (17.3 in) (female). In general, the bald head have long, shaggy coats ranging from white in color to red and their heads are bald. The tail of Cacajao calvus is bob-like and rather short for a New World monkey (about 5.9 inches (15 cm)), at only half the length of the body and head combined.Their scarlet red faces are due to the lack of skin pigments and plentiful capillaries that run under their facial tissue. This bright red facial skin is a sign of good health and allows for the determination of a healthy mate. The breeding season is between October and May. Their gestation period is approximately six months. Both sexes have a sternal gland, which might be involved in olfactory communication, especially during mating, when the female encourages the male to mate by releasing an attractive scent. The uakari generally live approximately 30 years and they have been known to live over 30 years in captivity.

These arboreal primates prefer to reside in seasonally flooded forests in the area of the Amazon River Basin, in the countries of Peru and Brazil. It is important that the uakari is arboreal (lives in the tree tops) because of the flooding of the forests and the water rising to great heights during the rainy season. During the dry season, Cacajao calvus comes to the ground to look for seeds and other food material. The overall diet of a uakari consists of 67% seeds, 18% fruit, 6% flowers, 5% animal prey, and buds. Their powerful lower jaw forms a pseudodental comb, which allows the uakari to open the hard surfaces of unripe fruits and eat the nuts that most other primates would not be able to open. They will also eat insects that happen to cross their path, however they do not specifically pursue this type of food.

The bald uakari can be found traveling up to 4.8 kilometers per day in multi-male/multi-female groups of 5 to 30 individuals, and even up to 100. It can be extrapolated from the general primate behavior of female philopatry that female uakaries are also philopatric. This means that males leave the natal group. The total size of their home range is between 500 and 600 hectares. This requires efficient territorial defense mechanisms. A few of these include specific vocalizations, wagging of the tail, and erection of the hair.

Due to the uakari's location, it is extremely common for these animals to contract malaria. Primates who have contracted the disease are noticeably paler and are not chosen as sexual partners as they do not have the desired natural immunity to malaria.