Grubb et al. (2003) and Groves (2001, 2005) recognized three subspecies: Papio cynocephalus cynocephalus, P. c. ibeanus and P. c. kindae. Subspecies kindae is now treated as a separate species. Limits to the distributions of the two remaining subspecies are poorly known. Historically, several forms of P. cyanocephalus have been described, some of which may merit subspecies status (e.g. P. c. jubilaeus from the Luangwa Valley) (Mittermeier et al. 2013).

Papio cyanocephalus hybridizes with P. anubis and there is a broad clinal hybrid zone between Laikipia district to the northeast of Mount Kenya and the Lower Tana River on the Kenya coast. Baboons in this more than 200-km wide region are intermediate and are difficult to allocate to either P. cyanocephalus or P. anubis (Mittermeier et al. 2013).

Papio cyanocephalus also hybridizes with Papio kindae, P. ursinus griseipes and Rungwicebus kipunji in the respective contact zones (Mittermeier et al. 2013). Whether their distribution overlaps with P. hamadryas in Somalia is not clear (Mittermeier et al. 2013).

Papio cynocephalus is listed as Least Concern, as the species is widespread and common, present in numerous protected areas, and there are no major range-wide threats believed to be resulting in a significant population decline.

The Yellow Baboon ranges from southern Ethiopia into Somalia, coastal Kenya, and northeastern Tanzania southwards to the Zambezi valley, where they are found in Malawi, northern Mozambique, and the far eastern part of Zambia (Jolly 1993). There are hybrid zones with Papio anubis near Sultan Hamud (2°02'S, 37°23'E) and Amboseli National Park in Kenya and Mkomazi National Park in Tanzania. As mentioned above, baboons in the broad clinal hybrid zone between Laikipia District, just to the northeast and east of Mt. Kenya, and the Lower Tana River, Kenya coast are intermediate in appearance; they become increasingly “yellow-like” in their phenotypes towards the Kenya Coast (De Jong and Butynski 2009, Zinner 2013). Yellow baboons are sympatric with Chlorocebus pygerythrus, Erythrocebus patas and Cercopithecus mitis.

There are two subspecies: P. c. cynocephalus occurs in the central and southeastern parts of the range including Zambia east of the Luangwa, Malawi, northern Mozambique, and most of Tanzania and P. c. ibeanus is found in far southeastern Ethiopia, southern Somalia, and southeastern and coastal Kenya.

This species is widespread and locally common, but patchily distributed over its extensive range.

The Yellow Baboon lives primarily in open and woodland savanna. Over much of its range, it is associated with fire-climax Miombo (Brachystegia) woodland. Both in this zone and especially to the northeast of its range, the species may also occupy dry bushland, thickets, steppes, and the coastal littoral (including mangroves). Fever Trees (Acacia xanthophloea) and Tortilis Trees (A. tortilis) are often used as both sources of food and shelter (Altmann et al. 2013). The Yellow Baboon typically forages in extended, well-spaced troops that may occasionally number up to 300 animals, though more typically average 30 to 80 individuals. The species is not territorial but, instead, uses home ranges that may overlap with other troops’ ranges. They drink almost daily, so their ranges tend to include a water source within a half-day’s journey (Altmann et al. 2013).

Like other members of the genus, Yellow Baboons are opportunistic omnivores. They primarily feed on the seeds, flesh, and pods of the leguminous trees including Acacia, Albizia, mopane (Colophospermum), and tamarind, all of which are seasonal staples. They also feed on grasses, shoots, fungi, lichens, and a range of animal prey, including invertebrates, lizards, birds, reptile and bird eggs, and small mammals. The latter include other primates, such as Vervet Monkeys (Chlorocebus pygerythrus) and Northern Lesser Galago (Galago senegalensis) (Altmann et al. 2013).

Yellow Baboons prefer foods with unusual chemistry, suggesting that this species has acquired special digestive adaptations. Such adaptations may help to explain why the boundaries of the species’ distribution do not follow specific geographic discontinuities but coincide closely with the distribution of a plant community (Jolly 1993, Kingdon 1997).

Although Yellow Baboons exhibit clear preference for woodland life, they can persist in secondary and highly fragmented vegetation, including areas that have been cultivated. In fact, some troops have adapted to living close to humans and regularly visit garbage dumps for foraging. While wild-foraging groups may spend approximately 70–75% of their time foraging and travelling up to 10 km per day, baboon troops that exploit garbage dumps forage for only 35–40% and travel only 2–4 km per day (Muruthi et al. 1991).

Extensive review and summary of the Yellow Baboon’s anatomy, behaviour and reproduction may be found in Altmann et al. (2013) and Zinner (2013).

There are no major threats to this species across its range, although some populations may be under pressure from agriculture and development projects. As other wildlife species decline and human populations increase, a potential increase in hunting pressure may be likely and trapping due to crop-raiding.

Both Papio anubis and P. cynocephalus are naturally infected with Treponema pallidum subspecies pertenue, the bacterium that causes human yaws and closely related to the bacterium that causes syphilis (T. p. pallidum) (see Harper et al. 2012, Chuma et al. 2019). In Papio sp., the infection appears to spread through sexual contact and is associated with open lesions in and around the genitalia of both sexes. The degree of morbidity varies, including some cases of deaths occurring in the Tanzania’s Gombe National Park’s Olive Baboons, when the genitalia are so badly damaged that urinary flow was obstructed (Wallis and Lee 1999).

Although the current hunting pressure and incidence of disease do not constitute “major threats”, both phenomena merit attention and monitoring.

Hunting of Yellow Baboons is not widespread, although occasional reports occur. As with other members of this genus, the species is often persecuted for crop-raiding activity as indicated in reports of trapping and killing by farmers in Tanzania’s Nguru (Doggart and Loserian 2007) and Nguu Mountains (Ceppi and Neilson 2014). Previous export of this species for use in medical research has apparently declined in recent years, although no current records are available.

This species is currently listed under Appendix II of CITES. It is listed as Vermin under the African Convention and is thus subject to legally sanctioned trapping and killing in certain areas. This may result in local extinction, if not controlled (Altmann et al. 2013).

Yellow Baboons are present in many protected areas. These include, for example, Amboseli National Park and Tsavo East National Park in Kenya; Ruaha National Park, Mikumi National Park, Udzungwa National Park, Mkomazi National Park, and Selous Game Reserve in Tanzania; and Liwonde National Park in Malawi.

They are susceptible to the spread of Treponema pallidum, which can have debilitating or even deadly consequences. Thus, research and ongoing monitoring for hunting pressure and disease transmission is recommended in assessment of the species’ long-term future. The effect of global climate change should be monitored; Altmann et al. (2002) noted measurable woodland loss in Amboseli since the 1970s, associated with temperature increases in the area. Thus, research into their habitat use, range, boundaries and reasons for separation into distinct subspecies could be useful for conservation planning.