Geladas are often referred to as the gelada baboon and the ʙʟᴇᴇᴅing-heart baboon but are not true baboons. These brown and grey primates are Old World monkeys that do bear some similarities to baboons. Twice the size of females, males are as big as a large dog and are equipped with vampiric canines, which they often bare at each other as a display of dominance or ᴀɢɢʀᴇssɪon. Both sᴇxes have large, fluffy manes, as well as distinct, hourglass-shaped, bald patches of skin on their ᴄʜᴇsᴛs. They also have the most opposable index fingers and thumbs than of any other primate.
They are in fact the only member of their genus (Theropithecus) that millions of years ago stretched from South Africa to Spain and into India, and there is no other animal like them. They also the last surviving species of aonce widespread group of grass-grazing primates.
Here are some facts about them:
1. Theropithecus is derived from the Greek root words for “beast-ape.”
There are two subspecies of gelada:
- Northern gelada, Theropithecus gelada gelada
- Eastern gelada, southern gelada or Heuglin’s gelada, Theropithecus gelada obscurus
They are the smallest vestige of genus Theropithecus
2. Geladas are found only in the Ethiopian Highlands, with large populations in the Semien Mountains.
They live in elevations 1,800–4,400 meters (5,900-14,450 feet) above sea level, using the cliffs for sleeping and climb up to the plateaus for their daily grazing and social activities.
3. The lifespan is about 15 years in the wild and up to 30 years in captivity.
4. There is sᴇxual ᴅɪᴍᴏʀᴘʜɪsᴍ in this species: males average 18.5 kg (40.8 lb) while females are smaller, averaging 11 kg (24.3 lb). The head and body length of this species is 50–75 cm (19.7–29.5 in) for both sᴇxes.
Both have dense, brownish to buff fur on the back and head, with lighter fur on the ᴄʜᴇsᴛ and belly, and dark colored faces (with pale eyelids) and extremities. Males have a long cape of hair on the back.
The gelada’s most striking feature is the hairless, hourglass-shaped pink or red area of skin located on the ᴄʜᴇsᴛ. On males, it is bright red and surrounded by white hair; on females, it is far less pronounced.
5. Geladas are the world’s most terrestrial primates, except for humans. Geladas are primarily diurnal. At night, they sleep on the ledges of cliffs. At sunrise, they leave the cliffs and travel to the tops of the plateaux to feed and socialize.
Geladas are the only primates that are primarily graminivores and grazers – grass blades make up to 90% of their diet. They eat both the blades and the seeds of grasses. When both blades and seeds are available, geladas prefer the seeds. The rest of their diet is made up of flowers, rhizomes and roots, herbs, other plants, fruits and the occasional insect.
This monkey is well adapted to its grazing feeding niche, with highly opposable thumbs and finely tuned index fingers for plucking grass, and a reinforced rear end ideal for scooting over the grass.
Geladas spend their days eating and socializing, like many other primates. Grooming, playing, and exercising their peculiar bipedal “shuffle gait” as they eat are paramount to gelada life.
6. Geladas have a diverse repertoire of over 30 different vocalizations — typical of highly social animals. Vocalizations can be combined into sequences to address necessary contact, reassurance, appeasement, solicitation, ambivalence, and ᴀɢɢʀᴇssɪve-defensive communications. Some calls are restricted to certain higher-status animals.
7. Geladas communicate through gestures, as well. They display ᴛʜʀᴇᴀᴛs 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.
8. Breeding and reproduction can occur at any time of the year.
After a gestation period of 5 to 6 months a female give birth to one baby (twins are rare).
Youngsters are usually born at night. They have red faces, black hair, and closed eyes. New mothers stay on the periphery of the group, as other females take a keen interest in her baby and may even try to abscond with it. The infant is carried on its mother’s belly for the first five weeks, and after that rides on her back. They can move independently at around five months old.
Geladas live in a complex multilevel society. The dynamic and complex social system consist of social units including reproductive units, all-male groups, and large bands. The smallest and most basic groups are the reproductive units, which are made up of one to twelve females, their young and one to four males, and the all-male units, which are made up of two to fifteen males. The next level of gelada societies are the bands, which are made up of two to twenty-seven reproductive units and several all-male units. The bands can number up to 1,200 individuals; some of the largest groups observed among any primate.
9. Their natural predators include dogs, jackals, leopards, servals, foxes, hyenas, and lammergeyers.
The usual response to predators is to flee to cliff faces, but in some circumstances, males may confront a ᴛʜʀᴇᴀᴛ and have even been observed to confront dogs and even mob and surround a leopard.
10. Due to the proximity of humans to many habitats, predator pressure is probably pretty low for the gelada.
Major ᴛʜʀᴇᴀᴛs to the gelada are a reduction of their range as a result of agricultural expansion and sʜᴏᴏᴛing as crop pests.
In 2008, the IUCN assessed the gelada as Least Concern, although their population had reduced from an estimated 440,000 in the 1970s to around 200,000 in 2008