Gelada baboon, Bleeding-heart monkey, Lion baboon, Bleeding-heart monkey baboon
The gelada (Theropithecus gelada) is a species of Old World monkey found only in the Ethiopian Highlands. Like its close relatives the baboons (genus Papio), it is largely terrestrial, spending much of its time foraging in grasslands. They are the last surviving member of a grass-grazing primate group, members of which were abundant and widespread in the past.
The gelada is large and robust, and it is covered with buff to dark-brown, coarse hair and has a dark face with pale eyelids. Its arms and feet are nearly black. Its short tail ends in a tuft of hair. Adult males have a long, heavy cape of hair on their backs. The gelada has a hairless face with a short muzzle that looks more similar to a chimpanzee's than a baboon's. It can also be physically distinguished from a baboon by the bright patch of skin on its chest. This patch is hourglass-shaped. On males, it is bright red and surrounded by white hair; on females, it is far less pronounced, but when in estrus, the female's patch brightens, and a "necklace" of fluid-filled blisters forms on the patch. This is thought to be analogous to the swollen buttocks common to most baboons experiencing estrus. In addition, females have knobs of skin around their patches. The gelada has several adaptations for its terrestrial and graminivorous (grass-eating) lifestyle. It has small, sturdy fingers adapted for pulling grass and narrow, small incisors adapted for chewing it. The gelada has a unique gait, known as the shuffle gait, that it uses when feeding. It squats bipedally and moves by sliding its feet without changing its posture. Because of this gait, the gelada's rump is hidden beneath, so is unavailable for display; its bright red chest patch is visible, though.
The natural range of this species is restricted to Ethiopia, where these animals mainly occur in the Semien Mountains National Park. During the nighttime hours, they typically sleep on rocky cliffs and outcrops. In the morning, geladas typically look for food in nearby grasslands.
Geladas are diurnal and highly social animals, forming so-called one-male units (OMUs). These are female-led groups that consist of a single male and multiple females with their young. When a male from the outside challenges the male of the OMU in order to displace it, females of the group may support or oppose both of them, accepting the winning male and fiercely driving away the defeated one. Various OMUs occasionally share the same area, thus forming larger units called bands. As these animals are non-territorial, they may be observed grazing in separate bands in areas with abundant food without any conflicts. Males and females can often be observed grooming each other. In general, all members of the community participate in grooming, which enhances social bonds within the OMU. Adult geladas use a diverse repertoire of vocalizations for various purposes, such as contact, reassurance, appeasement, solicitation, ambivalence, aggression, and defense. They sit around and chatter at each other, signifying to those around that they matter, in a way, to the individual "speaking". Geladas communicate through gestures, as well. They display threats by flipping their upper lips back on their nostrils to display their teeth and gums, and by pulling back their scalps to display the pale eyelids. A gelada submits by fleeing or presenting itself.
Geladas have a seasonal diet. As strictly herbivorous animals, they generally feed upon grasses, blades, seeds, and bulbs.
Geladas are polygynous, which means that one male gets an exclusive right to mating with multiple females. Although Geladas can mate at any time of the year, births appear to peak during the rainy season. The gestation period lasts for 5-6 months, yielding a single baby, which feeds upon maternal milk for 1-1.5 years. The infant is mainly cared by its mother, who will carry, groom, nurse, and protect the baby until the latter reaches the age of independence. Meanwhile, the father will take little part in rearing its offspring. Males of this species become reproductively mature at 5-7 years old, whereas females are ready to produce young when they are 4-5 years old.
One of the biggest threats to the population of this species is habitat reduction due to the development of agriculture. Additionally, Geladas are considered pests and thus shot because of destructing crops.
According to the IUCN Red List, the total population of the gelada is around 200,000 individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers are decreasing.
On one hand, due to their grass-based diet, Geladas control plant communities of their range. On the other hand, they contribute to the aeration of soil through their habit of digging for roots, tubers, and grass rhizomes. Additionally, geladas may be an important prey species for many local predators.