The total size of the group's 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. The 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. Its 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 bald uakari lives approximately 30 years and has been known to live over 30 years in captivity. 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. Conservation The conservation status of this species was changed from near threatened to vulnerable in the 2008 World Conservation Union (IUCN) Red List because the species has declined at least 30% over the past 30 years (three generations) due to hunting and habitat loss. This is considerably better than the 1994 assessment which found it to be endangered, followed by the 2003 assessment which found the species to be near threatened. Although the conservation status has improved, actual population numbers are on a decreasing trend. Since it only lives in white water flooded forests, it is very susceptible to human impact (i.e. land acquisition for agriculture and/or pastures). Forest loss and hunting are the two most prominent threats to the bald uakari. Between 1980 and 1990 it was found that an average of 15.4 million hectares of tropical forests were destroyed each year and the Neotropics are facing forest loss in areas such as the southern and eastern parts of the Amazonia. In 1997, the Amazon Basin experienced the highest rate of forest destruction of the remaining tropical rainforests worldwide. Logging of hardwoods is a major contributor to overall destruction as large-scale logging disrupts the continuity of forest canopies. Canopy disruption and forest loss directly affect uakaris because of their arboreal lifestyle and adaptations for seed food consumption. Additionally, Cacajao calvus populations are located so close to the Amazon River that there is a higher risk of human hunting from