Yvonne de Jong is a National Geographic grantee working to track down what may be Africa’s least understood large animal, the Desert Warthog.
In our search for warthogs in central northern Kenya, we drive from Marsabit, across the Koroli and Chalbi Deserts to Sibiloi National Park (just south of the Kenya – Ethiopian border). It is the end of the dry season in a region where the annual rainfall averages just 250 mm per year (and in some parts it may not rain for several years).
The ground alternates between deep red sand and bare, black, volcanic rock, and there is the rare oasis. Vegetation is sparse, and the birds and mammals are few. Most of the life of this region is supported by the narrow bands of poor forest found along the ‘sand rivers’….rivers that typically flow for but a few days or weeks each year. Only the most desert-adapted species are able to endure this severe environment.
Given it’s name, we anticipate that the ‘desert’ warthog is present here…and that the common warthog is absent. There is, however, a puzzling record of common warthog in our database for Sibiloi National Park (meaning ‘Cradle of mankind’). A primary aim of our survey is to determine which species of warthog is present in this region.
Slowly we drive northwards along the eastern shore of Lake Turkana towards the Ethiopian border. Much of the area is severely degraded as a result of over-grazing and over-browing by sheep, goats, donkeys and camels. Warthogs are not to be seen! The acacia shrublands of Sibiloi National Park and its surroundings seem slightly more likely to support at least a few warthogs.
A brief sightings of four warthogs, and examination of three warthog skulls at the camp of the famous Koobi Fora Research Project, indicate that the common warthog is present. Equipped with twelve infrared camera traps and a variety of ‘irresistible’ baits (sardines, soya sauce, bananas, dry cat food), we are confident of capturing some of the more shy and obscure mammals of the area.
The biggest surprise is the capture of sounders (or groups) of common warthog that are foraging at night…common warthogs are typically diurnal. It appears that the common warthog in this desert environment has ‘swapped’ its strictly diurnal lifestyle for a nocturnal or cathemeral (active during the day and night) one.
Nocturnal activity by warthogs has been rarely reported. To our knowledge, there are only two other records of nocturnal activity by common warthogs; one for a forest in western Africa and one for a forest in the Kenya Highlands. Just north of the equator, at an altitude of about 600 m, it is hot during the day. Being active at night is probably an adaption by common warthogs that enables them to live where it is hot, where food is probably often scare, and where there is no drinking water for several months at a time.
In all of the areas where we encountered common warthogs, there were dense clumps of doum palm (Hyphaene thebaica). This is probably a keystone species for the common warthog and other species in northern Kenya, providing food, water, and dense shade/cover.
That there was considerable moonlight during the nights when the camera traps captured common warthogs raises the question as to how reliant common warthogs are on moonlight for nocturnal foraging. Do they forage on dark, moonless, nights?…perhaps using their very acute sense of smell to guide them along?
The other question raised during this survey is, ‘Why did we find common warthogs where we expected to find desert warthogs? The ecological niche and environmental limits of the desert warthog a poorly known. Perhaps ‘desert’ warthog is a misnomer…and it is the common warthog that is able to exploit the more xeric habitats.
Other posts from Yvonne’s expedition: Quest for Kenya’s Desert Warthog