Inhabiting a broad swath of arid savanna woodlands just north of equatorial Africa lives one of the most remarkable monkeys that you have likely never heard of. The patas monkey (Erythrocebus patas) survives in these difficult places with the help of several unique adaptations that allow it to carve out a living in ways unlike most other primates.

Unlike most monkeys, patas spend a great deal of time moving on the ground rather than in trees. The small Acacia trees that dot their open habitats are widespread and force them to roam far each day, sometimes over 6 kilometers, to acquire enough food to survive. That’s far for a monkey not much larger than a house cat. Many of the patas monkeys’ closest relatives live in forests and consume fruits, leaves, and insects. However, the patas’ diet contains large quantities of small arthropods, gums, and plant parts, a composition highly unusual for a monkey of its size. Given their odd diet and challenging environment, it is surprising that patas monkeys seemingly flourish so long as there is available water somewhere nearby. They breed seasonally, and many females reproduce every year, a remarkable feat for a monkey of this size. This is possible due in part to this species’ accelerated rate of growth which allows offspring to be independent of their mothers as early as six months of age! Another feature that may explain this remarkable ability to thrive in these spartan habitats are their relatively long limbs. Longer legs decrease the amount of energy it takes to move, which would allow patas monkeys to maximize the energy gained from their small, widely dispersed foods. These long legs also allow them to run remarkably fast, up to 55 kilometers per hour (35 miles per hour). This likely aids in their ability to evade lions, cheetahs, leopards, jackals, wildcats, caracals, hyenas, and the numerous other terrestrial predators that they might encounter. Of course, escaping from other threats like martial eagles might require a different strategy.

Unlike their close relatives, the pesky vervets (Chlorocebus pygerythrus) that thrive throughout Africa both in the wild as well as around humans, patas monkeys seem unable to depart from their unique way of living. Sadly, because of this, their fate as a species is seemingly tied to the existence of these savanna woodlands. One of the biggest threats to their habitats are humans cutting the trees to make charcoal, trees that the patas rely on for most of their food and even a modicum of shelter.

References

1. L. A. Isbell, Diet for a Small Primate: Insectivory and Gummivory in the (Large) Patas Monkey (Erythrocebus patas pyrrhonotus). Am J Primatol 45, 381-398 (1998).
2. L. A. Isbell, J. Pruetz, M. Lewis, T. Young, Locomotor Activity Differences Between Sympatric Patas Monkeys (Erythrocebus patas) and Vervet Monkeys (Cercopithecus aethiops): Implications for the Evolution of Long Hindlimb Length in Homo. Am J Phys Anthropol 105, 199-207 (1998).
3. Y. A. de Jong, T. M. Butynski, L. A. Isbell, C. Lewis, Decline in the geographical range of the southern patas monkey Erythrocebus patas baumstarki in Tanzania. Oryx 43, 267 (2009).
4. L. A. Isbell, T. P. Young, K. E. Jaffe, A. A. Carlson, R. L. Chancellor, Demography and Life Histories of Sympatric Patas Monkeys, Erythrocebus patas , and Vervets, Cercopithecus aethiops, in Laikipia, Kenya. International journal of primatology 30, 103-124 (2009).
5. N. Nakagawa, Seasonal, Sex, and Interspecific Differences in Activity Time Budgets and Diets of Patas Monkeys (Erythrocebus patas) and Tantalus Monkeys (Cercopithecus aethiops tantalus), Living Sympatrically in Northern Cameroon. Primates 41, 161-174 (2000).
6. N. Nakagawa, H. Ohsawa, Y. Muroyama, Life-history parameters of a wild group of West African patas monkeys (Erythrocebus patas patas). Primates 44, 281-290 (2003).
7. L. A. Isbell, J. Chism, Distribution and abundance of patas monkeys (Erythrocebus patas) in Laikipia, Kenya, 1979-2004. Am J Primatol 69, 1223-1235 (2007).