The Rheper

Art done by Tortoiseman on reddit

The Rheper (Simialuctor unguespollicus, thumb-clawed grapple-monkey) is a carnivorous descendant of the Rhesus Macaque. It resides in the forests and swamps of Arabia, east Asia, south Asia and southeast Asia during the Calidocene epoch.

Evolution

Their evolution first began during the holocene extinction, already adapted to survive negative human activities and take advantage of them, the rhesus macaques took over cities after humans died off. To cope with a small amount of fruit or vegetation, they started to hunt for small vertebrates. As their prey got bigger over time they evolved better equipment for taking down larger prey and developed an ambush strategy as to have a lower chance of being injured and to conserve energy. This strategy was changed as forests came back and the monkeys returned to the trees. Most returned to being normal monkeys with a diet of leaves and fruit, the ones going down the carnivorous rote would become the rhepers. 

Biology and behavior

The Rheper is a mesocarnivore with 65% of its diet being comprised of meat. They are slightly smaller than their ancestors. They hunt medium sized herbivores and thus have the adaptations necessary to do so. Each monkey has a longer snout with sharp incisors and thick canine teeth to tear into flesh easier, some of their molars have also attained a shape similar to carnassials. Each Rheper has claws that replace its nails along with a longer more talon-like claw on its thumb. They have claws on the feet as well. They have a shorter but bulkier tail that helps them stay balanced while taking down prey.

The hunting strategy goes as follows. The monkey first jumps from a strong branch onto its prey, in order to avoid being bucked off by its prey the rheper will grapple onto its prey with the hands and feet, while the prey flees it slowly moves towards the neck before deliver a fatal blow to its prey by tearing out its throat out with the claws on the hands. 

Rhepers live in groups of 4 adults comprising of 1 male and 3 dominant females. This quartet will mate from when they hit maturity at 3 to sterility at 19, this mating season usually occurs during the fall. Sometimes fights will break out between the females over who gets to mate but they rarely end in death. Usually this quartet will produce 4-5 children and each child learns how to hunt from its mother. Once a child reaches maturity it will go out on its own to form its own quartet with other monkeys.

Despite having lower neuron density and smaller brains, they still exhibit a degree of intelligence with planning and strategy going into their hunts as well as some of that brainpower going into a social system and emotional behavior reminiscent of their ancestors.