Bruce: Male, born August 11, 2006 at Buffalo Zoological Gardens. Arrived at the Zoo on June 19, 2008.
The addax is a stocky, predominately white, medium-sized antelope in which both sexes sport long spiral horns. Its face is light gray or beige with white patches around the eyes and a wig-like dark brown tuft of hair on the crown of the head. Its hooves are broad and splayed which allow it to walk effortlessly over loose desert sand, but its stocky build and wide hooves make it a slow runner. The remoteness of its habitat has protected it from most predators, so speed wasn’t necessary, but the arrival of humans with long-range vehicles has opened it up to increased hunting pressure.
Longevity
A typical lifespan for an addax in a zoo is about 11 or 12 years. A very few individuals may live as long as 24 years, but most individuals don’t reach these oldest ages. Lifespan in the wild is not well known.
Behavior
A true desert species, the addax is able to utilize some of the most arid and desolate habitats on earth. They survive in places where it seems impossible that life can exist. They have several physical adaptations for life in such a demanding climate – for example, their pale coloration reflects radiant heat, varying hair length helps with thermoregulation, the barrel shaped body reduces surface area and their large splayed hooves help them move efficiently on loose sand. Along with these physical changes, the addax has also developed behaviors that help it survive. They are active mainly during the night when it’s cooler and they can avoid the scorching sun. They rest during the heat of the day in whatever shade they can find. They often scrape areas of sand with their hooves and horns in order to move aside the hottest layer and reveal the cooler sand below before they lie down. Addax are almost continually in motion as they move throughout the desert in a search for food. They respond to the growing season of specific plants that provide them with needed moisture. They also migrate in response to weather changes such as summer rains, waves of humid air, and nighttime dew which all affect plant growth. Addax generally live in small herds of up to 15 animals of mixed ages and sexes. These small groups may come together temporarily in areas of exceptional grazing, which may have given the appearance of much larger herds. Because of recent periods of severe drought, herd size is seldom more than a half-dozen individuals. Dominance hierarchies are mainly established based on age, with older animals ranking highest.
Reproduction
Addax calves are born mainly in the winter and spring. They are born after a gestation period of 257 to 264 days. The calves are pale cream in color without the striking facial markings that they will develop as they mature. They weigh about 13 lbs at birth and are able to walk and follow their mother shortly afterwards. They are weaned at 7.5 months and reach sexual maturity at around 2 years for males and 2 – 3 years for females. A healthy female addax can produce a calf each year during her prime.
To learn more about the conservation efforts at the Philadelphia Zoo, click here.