There is a wonderful African folk tale that gives insight into the biology and life of the dik-dik. One day Juma, the king of all the dik-diks, was out walking through his kingdom when he inadvertently tripped over and fell into a huge pile of steaming elephant dung. He was understandably furious, so he called a meeting of all the dik-diks of the land at which he said the dik-diks were to take revenge on the elephant. He told them that while dik-diks were small, together they can be big and henceforth the dik-diks were all to defecate in the same place and produce a dung heap so big that it would trip up a passing elephant so that justice could be served.
Dik-diks toilet behaviour
As with so many of these African folklore stories, there is a modicum of truth that arises from careful observations of the animals. Dik-diks do indeed produce piles of dung, in latrines that several dik-diks will defecate on, although the evidence looks as though it relates more to territorial defence than to seeking revenge on elephants. There is also something of a ritual that takes place when a family group of dik-diks approach a latrine. The female, who doesn’t have horns but is bigger than the male, approaches the latrine first, urinates in a characteristic hunched position and then accentuates this hunched position when she defecates.
Next, the fawn walks onto the midden to defaecate and last, the male approaches the dung pile, smells the dung of the female and scratches it backwards as he urinates on it, and then he does a 180o turn and urinates again. He makes a few more turns and defecates before doing one final 180o pirouette and completes his ritualized dunging behavior. After this, both the male and female go to a nearby bush or piece of grass and open their preorbital gland to deposit a pea sized extract onto the bush.
This pre-orbital gland is the obvious opening just in front of the eye and while marking, looks as though the antelope is poking its own eye out with a stick. Many antelope species use latrines to communicate their presence, although, in most species, only the males use the latrines so for females and fawns to utilize them is intriguing. Some workers have suggested that the characteristic hunched position when defaecating is also a ritualized visual signal that reinforces the scent marking to their neighbours. There can be as many as 20 dung piles within one territory and dik-diks from both neighbouring territories will use the same latrine to confirm that this is the edge of a territory. While neighboring dik-diks will chase each other it is exceedingly rare for them to ever make contact and fight. Interestingly, there is often an old midden close by the active one and I wonder if they abandon middens when they lose a mate, or the territory is taken over by new individuals.
Latrines, territories, and predator avoidance
As a very small antelope, dik-diks are vulnerable prey to any passing predator and are taken by more than 20 predator species: lions, cheetahs, leopards, African wild dogs, martial eagles, jackals, caracals, servals, pythons and more. Without question, the selective pressure on these animals to avoid predation is massive and their modus operandi is to know a section of bush so well that with every twist and turn they can spot a predator coming from a distance, hide and move around the vegetation to avoid them. They know their area so well that they can dodge any predator attack and will not try to outrun them but dive into a hiding spot, so the predator misses them. In the meantime, they can’t be out grazing for hours at a time leaving themselves exposed to all the passing predators, so they are specialized browsers taking just the highly nutritious leaves and buds from the trees and shrubs they feed on, mostly in the evening and before midnight but also in the early morning, when is the perfect time to photograph them. Compared to other antelope species, they spend an inordinately long time either ruminating or simply hiding from predators.
In my experience the best places to see dik-diks are close to the safari camps. Ndutu safari camp in the south of the Serengeti is a case in point. Situated in the arid scrub, every time you turn around you see a pair of dik-diks. Initially I thought this could be simply because the habitat was perfect, and the predators avoided the camps – but this was not really true since I bumped into a lion one night. Maybe reduced predator pressure coupled with nocturnal lighting that allows them the means to browse more at night, and some access to water may be driving this preference.
Young production
One benefit of the highly nutritious food is that the females produce 2 fawns a year, but only ever one at a time – yet another form of predator avoidance I wonder? They produce these fawns so fast that they are lactating with one fawn while pregnant with the next. Like most antelopes, she leaves the fawn “lying out” and visits it for periods of about 10 minutes to feed, four or five times a day. As the fawn gets larger, she takes it to a new hiding place every day and by the time the fawn is 6 months of age, the fawn spends most of its time with the male while the female is caring for the next offspring. At this age, the parents start to push the young off to find their own territory and no doubt this is a period of heavy mortality before they establish and get to know their own territory.
Water retention and the strange nose
Dik-diks inhabit semi-arid areas where access to water is difficult and should they get to a waterhole draws the undesired attention of predators. This is even more an issue for such a small antelope that has a high surface area to body mass ratio and so heats up fast and loses water much faster than a larger species. The dik-dik exhibits several amazing adaptations. Many of these are subtle like adaptations in kidneys that can reabsorb urea, passing highly concentrated urine, water absorption physiology and reduced density of sweat glands compared to cattle, but similar to that seen in camels.
Perhaps the most obvious adaptation is their remarkable flexible nose or proboscis which is similar in structure to the remarkable noses of the unrelated tapir and saiga. The nose is lined with multiple blood vessels where the blood is cooled through evaporation of water from the mucosal membrane, a very economical method when water loss is a critical issue. They even lick the condensation that appears on the end of the nose to help water retention. The cool blood circulates to a sinus where it cools the blood destined for the brain and keeps the brain sharp and active. Cooling can be increased through panting behaviour where the flexible nose acts as a bellows and water loss is prevented through fine hairs and small nostrils.
Conservation and Conclusion
The dik-diks are a group of four very similar looking species restricted to the arid regions of Africa and only one species, the Silver Dik-dik, restricted to Somalia, is decreasing and of concern although we lack knowledge. The three other species are not threatened and are stable although the continual loss of habitat must mean numbers are falling. The species we have focused on here is primarily Kirk’s Dik-dik (Madoqua guentheri) since this species is the prevalent species in East Africa and the one photographed the most by our readers. Interestingly this species has a really disjunct distribution with a large population in East Africa, (southern Kenya and Tanzania) and another in northern Namibia and western Angola. The explanation is that once they were all one population, but increased humidity and development of more humid forests split the population. Another common species, that looks very much like Kirk’s Dik-dik, is Guenther’s Dik-dik (Madoqua guentheri), found in Northern Kenya and up through Ethiopia, Somalia, and South Sudan. The final species is Salt’s Dik-dik (Madoqua saltiana) that occurs to the east of Guenther’s in Somalia and up through Ethiopia to Eritrea.
The Dik-diks are doing well amongst the antelope species where 25% of the species are threatened and 62% are declining. The antelopes of arid and desert areas appear also to be the most vulnerable now, so we hope this detailed look at the dik-dik does two things. First, draws your attention away from the large and charismatic species of the African bush to appreciate the subtleties and beauty of the less obvious small antelopes. Second, to provide you with biological insight and understanding that you can apply in your photography to reveal stories about these and other antelope species.
