Chimpazee, called Osa or Elegbede in Yoruba languagem is the closest animal relative of humans, sharing 98% of human genes. Chimpanzees are hefty, four limbed, long-armed and short-legged primate found predominantly in moist and dry forests, and forest galleries extending into savanna woodlands. Chimpanzees show learned behaviors, long memories and some extraordinary use of tools. They are omnivorous, and their diet is highly variable according to individual populations and seasons. Leaf swallowing that is found to be a feature of the Nigerian Chimpanzee is believed to serve self-mediatory purposes.
The Nigerian-Cameroon Chimpanzee, Pan troglodytes ellioti is found only in Nigeria and Cameroon, north of the Sanaga River. It is the most endangered subspecies, accounting for only 2.5% of the continent-wide species population. About 1,500 Chimpanzees are found in Nigeria’s Gashaka-Gumti National Park, and this figure accounts for 23% of the total Nigerian population of the primate. Chimpanzees are also found in a mosaic landscape of semi-deciduous forest and savannah in Nigeria. Ngel Nyaki forest is home to a population of the rare and endangered Nigerian chimpanzee, Pan troglodytes subsp. villerosus
HIV-1 epidemic has been implicated as been a result of the zoonotic virus transmission from Chimpanzee, subspecies Pan troglodytes troglodytes to man, but this is to be differentiated from the Nigerian Chimpanzee, the Pan troglodytes ellioti subspecies.