The desert elephants of the Northern Namib Desert in Namibia’s Kunene Region live in an extremely arid environment of less than 150mm of annual rainfall and periodic drought. They are one of only two populations of “desert” elephants in the world (the other is in Mali, North Africa). They are not a unique species or subspecies of elephant but an "ecotype": a population unique in that it has adapted to this extreme environment through learned behaviors, rather than genetic adaptions.
Based on historic records and archeological evidence, Namibia's desert elephants once ranged along ephemeral rivers from the Kunene River in the north (along the border with Angola) to the Kuiseb River in central Namibia (at the northern edge of the massive dune fields that characterize the Southern Namib Desert). However, because of historic over-hunting, wartime poaching, and ongoing human-elephant conflict and poaching, the range of desert elephants has been reduced to five subpopulations along the Hoarusib, Hoanib, Uniab, Huab, and Ugab Rivers. There are approximately 150 desert elephants remaining.
Our study area includes the three northern subpopulations, found in the Hoarusib, Hoanib, and Uniab river drainages, including Skeleton Coast National Park. These are the same three subpopulations studied by P.J. Viljoen from 1975-1983, allowing a long-term comparison of population dynamics, behavior, habitat use, and causes of mortality. We monitor the population with field observations and by constantly updating a photographic inventory of all the elephants, along with reports and photographs from a wide-ranging network of Namibian collaborators interested in their conservation. Genetic data is obtained non-invasively from fecal DNA to determine relatedness of individuals and paternity of elephant calves. The group, Elephant-Human Relations Aid (EHRA) monitor the Huab and Ugab subpopulations.
We share the results of our scientific research and report on current desert elephant status to collaborators, stakeholders and decision-makers. These individuals and organizations include, but are not limited to: Namibian NGOs (Integrated Rural Development and Nature Conservation (IRDNC), and Tourism Supporting Conservation (TOSCO), affected conservancies, tourism concessions, local guides, interested individuals, the Desert Lion Project, and MET. Copies of reports, scientific papers, and training materials are freely provided . These efforts have increased local appreciation for, and economic valuation of, elephants, thus contributing to overall elephant conservation in the Kunene and a sustainable tourism sector.
We (Dr. R. Ramey and Dr. L. Brown) began our long-term research program in 2006, focusing on questions regarding elephant social organization and genetics in the Hoarusib and Hoanib Rivers. This research was initially in collaboration with Dr. K. Leggett, until he left in 2009 and we fully took over the project. We subsequently expanded the study area, as well as conservancy and IRDNC involvement in the project (via our Namibian collaborators, R. and T. Vinjevold), which has proven to be mutually beneficial to our research, local communities, and desert elephant conservation in general.
Through the mutual sharing of information and increasing ability of guides and game guards to identify individual elephants and family groups (and knowing the history of both of these), there is now more empowerment and incentive within the conservancies to conserve desert elephants.
Desert elephants are approximately the same body size as savannah elephants, although their bodies may appear less bulky, probably from a lower food intake. Their feet appear to be wider, probably as a result of walking long distances on sand, which causes the footpads to be splayed out.
A full-grown male (bull) elephant can weigh up to 6 tons (~6000 kg) and be 4m high at the shoulder. Females are usually a little more than half that weight.
Elephants are known to live 60+ years in captivity, but most probably have shorter lives in the wild. We do not know the exact ages of the oldest elephants in the desert population, but estimate that some may be 40-50 years old. That means that the older elephants in the population are survivors of poaching during the War of Independence and Angolan War.
Elephants have only four teeth, one on each side of the upper and lower jaw. They grow six sets of new teeth throughout their lifetime, and may die of starvation in old age when they can no longer chew.
Tusks are specialized teeth that continue to grow throughout an elephant’s lifetime. Tuskless-ness is an inherited trait that tends to run in family groups. The tuskless trait is found in some desert females, never in males, however both males and females are prone to tusk breakage, which may make them appear tuskless for a time, until the tusk grows out again. Subpopulation vary widely in their degree of tusklessness, with up to one-third of females being tuskless in the Hoanib subpopulations.
Elephants prefer to drink daily, but can go up to three days without water if necessary. Bulls will drink up to 160 liters per day. We have discovered that elephants dig wells in sandy river beds to purify their drinking water. Water, dust, and especially mud are sought out for bathing and coating the skin against sun and biting insects.
Elephants eat almost any vegetation, including grasses, herbs, shrubs, leaves, bark, seeds, and fruit. Adult bulls can consume 250kg daily, although females eat less than that. During the wet season they prefer green grasses, shoots and buds, but in the dry season desert elephants have to rely on woody vegetation, primarily camelthorn (Acacia erioloba), mopane (Colophospermum mopane), and Ana trees and seedpods (Faidherbia albida).
Elephants communicate with each other using scent, touch, and a variety of sounds, including low frequency rumbles and infrasound (which at <40Hz is below the level of human hearing) that can travel 5-10km or more.
An older female (cow) leads the family and is called the matriarch. Family groups are usually related, and include the matriarch, her sisters, daughters, and their young. Related family groups are called “bond groups” or “kin groups,” and groups that share the same seasonal habitat are known as clans. Being the oldest, the matriarch has the longest memory and knowledge of water sources, seasonal foods, and migration routes to help her family survive.
Male offspring leave the family group at puberty, usually around 12-14 years old, and often form loose bachelor herds. The young males may attach themselves to older dominant bulls that act as “mentors,” guiding the younger ones through their teens and twenties.
Males undergo periods of heightened sexual condition called musth, when they become restless and more aggressive in their pursuit of estrous females. At his point bulls may clash and even fight, but will resume more tolerant relations once the musth period is over.
Females usually produce their first offspring around 10-12 years of age, after a 22-month gestation period. Calves depend on their mother’s milk until the age of two, but most will suckle until the birth of the next calf, usually at 3-4 years. In the desert population we have seen calves as old as six, still suckling.
Family groups of desert-dwelling elephants are smaller than those found in the savannah. In Etosha, for example, one may see 20-30 elephants in a family group. Family groups are generally all related females (grandmothers, mothers, daughters, sisters, aunts) and their juvenile offspring. In the desert, elephant family groups are quite a bit smaller, often consisting of a single adult female and her calves, or two adult sisters with their dependent offspring.
In the northwestern Kunene Region, where rainfall averages less than 150mm annually, desert elephants will migrate long distances in search of food and water. For example, some of the elephants of the Hoarusib River migrate to the Hoanib River, over 70km distant, to feed on the seedpods of the Ana trees (Faidherbia albida) when they are ripe, or to the Hoanib floodplain to feed on grass. (Ana trees are found in the Hoarusib River, but are not as large or as numerous as in the Hoanib River). Typically the elephants will drink and eat constantly for a couple of days, then make the long journey across the barren gravel plains in one long push, usually at night when the temperature is cooler.
Historically, elephants even migrated 190 kilometers from the Kunene River on the Angolan border, to the Hoarusib River. (P.J. Viljoen, who studied the elephants of Namibia’s northwest in 1975-1983, documented this migration.) However, the Kunene River elephants were poached out at the end of the Angolan War, thus bringing a tragic end to this spectacular long-distance migration.
From satellite radio collar data during his study, K. Leggett found that adult bull elephants in the northern Kunene roam over very large distances. One collared bull (WKM-10) covered an area from Skeleton Coast Park in the west, to Etosha National Park in the east, over the course of a few months. Female desert elephants on the other hand, have smaller and somewhat more predictable movement patterns, tending to stay in or near the ephemeral rivers where water and forage are more readily available. Unfortunately, we have documented two elephant family groups that have abandoned migration due to the premature and tramatic loss of their matriarchs.
The desert elephants also make excursions into the low mountains, following traditional paths that are quite narrow and precipitous. They go in search of Commiphora, small bushes that are fragrant with resin, and known more commonly as myrrh. Elephants will go to great lengths to locate, uproot and eat entire plants, presumably because of the sweet taste, or possibly for medicinal purposes. (There is a sustainable development project in Orupembe, organized by IRDNC, where Commiphora resin is harvested for sale to perfume companies.)