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ZooNooz Article - December 2005
Focus on: Addax
Story by BRIGITTE DUBA
Photograph Leonie Saville
Illustration Ngaire Sales
Desert Survival
Crepuscular is not a word you hear often, but to the Addax, it’s not just a word, it’s a way of life! The Addax is a desert dweller and being crepuscular means that it’s most active at dawn and dusk, a perfect lifestyle to escape the heat of the day.
Everything about this large antelope is suited to desert living. Its coat is greyish-brown during winter but in summer it becomes almost white to reflect the sun’s scorching rays and keep its body cooler. White markings are also present on the rump, belly, limbs and face to break up its solid body outline. The clumsy appearance of the Addax is attributed to the combination of heavy head and shoulders, thick short legs and slender hindquarters; it’s unable to achieve high speeds to outrun natural predators, so camouflage is essential.
Water loss is reduced even further through a cooling system that lets the body tissues tolerate temperatures up to 60ºC. As its body temperature increases, its breathing rate also increases by up to seven times faster
The Addax may be heavily built and a slow runner but it is equipped with especially large and wide spreading hoofs to make walking on soft sand a breeze, and its well-developed dewclaws, just above the hoof at the back of each foot, prevent it sinking into sandy desert soils.
A male can weigh up to 135 kg while females are lighter and smaller, up to 90 kg. The maximum length from head to rump is 1.7 metres and height from toe to shoulder is 1.15 metres. Long spiral horns with three twists are present on both males and females.
The Addax is considered one of the world’s rarest mammals (LS) |
The Addax is nomadic and possesses heightened senses to locate sprouting patches of desert vegetation after rain. It does not need to drink at all and obtains moisture from dew on plants.
To balance its low water intake, it produces highly concentrated urine and hard pellet-like faeces. Water loss is reduced even further through a cooling system that lets the body tissues tolerate temperatures up to 60ºC. As its body temperature increases, its breathing rate also increases (up to seven times faster). This speeds up the rate of evaporation of air passing through the moist nasal passages and so cools the blood traveling to the brain, preventing it from overheating.
Feeding and breeding
Food is mostly coarse grasses, acacia and herbs and the Addax will travel vast distances following sporadic rain to forage. The herd travels in the cool evening then rests and shelters from the heat and strong desert winds of the day by digging beds in the sand, nestling amongst the bushes for shade.
The female Addax produces only one calf per year after a pregnancy of about ten months. The birth season follows the rainy season, usually September to January, and avoids the cold. Sexual maturity is reached by two years and in captivity an Addax may live to 25 years.
The numbers game
The Addax is considered one of the world’s rarest mammals and classified as critically endangered. Single herds of up to 200 once roamed throughout the arid areas of North Africa and over most of the Sahara and sometimes herds joined and numbered up to 1000. Now only found in small pockets in Chad, Mauritania, Niger and Mali, the Addax occurs singly or in small groups of two to four.
Probably the only reason the Addax survived at all was due to its ability to retreat and survive in sand dunes too harsh for hunters and human habitation.
The decline is mainly due to hunting for meat and leather and the expansion of farmlands rather than from natural predators such as lions, leopards and hyenas. Natural disasters, such as prolonged drought, as well as mining exploration, increased human populations and invading tourists, have also contributed.
The 1960s almost saw the beginning of the end for the Addax – it had an estimated population of only 5000 and was dropping. By 1986, the decline had slowed in remote parts of the Sahara but population was still fewer than 2000. Probably the only reason the Addax survived at all was due to its ability to retreat and survive in sand dunes too harsh for hunters and human habitation.
By 1996 the population consisted of fewer than 200 in Chad, 50 in Mauritania, 50 on the border of Mali and 200 in Niger, and it was considered extinct in Sudan.
The Addax's horns have 3 twists (NS) |
Despite all obstacles the Addax survived and now, with the help of zoos around the world, things may be changing. Captive breeding programs introduced in 1990 are steadily increasing Addax populations in zoos, and herds have been established in secured enclosures in wild areas in Tunisia, Morocco and Libya.
Estimated numbers have now increased to 2000. Australia has also played its part in preserving this magnificent creature with Addax being first imported in 1992 for breeding programs at Werribee and Monarto Zoos. Taronga Western Plains Zoo initially had three males, which in 2004 were joined by two females from Werribee Zoo.
This year two calves have been born, a female, Chari, and a male, Chad.These are the first Addax to be bred at Taronga Western Plains Zoo. This is certainly something to celebrate in the fight for survival of an amazing desert-adapted creature!
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