Mammals: Spiral-horned Antelope

Range: Africa, below the Sahara Desert Habitat: wetlands, thickets, grasslands, and forests, depending on species

Built-in corkscrews

If an animal is called a “spiral-horned antelope,” you better believe it’s going to have a set of spiraling horns on its head! All of the bulls (males) have these impressive hood ornaments, and in the bongo and eland species, the cows (females) have them, too. It is important to note that horns are different from antlers in many ways: horns do not branch and are not shed each year as antlers are. Horns are there to stay for the animal’s lifetime and are actually part of the skeleton. They are made of hollow bone covered with an outer layer of keratin. So how do they grow in a spiral? Well, the twisting is a result of a growth pulse where the horn material grows faster and thinner at certain times, and then thicker and slower at other times. An animal’s genes control growth pulses.

Adaptable antelope

The nine species of spiral-horned antelope have managed to make use of many major African habitats below the Sahara Desert. They are often found in areas between different types of vegetation. One reason for this could be that they are able to eat a variety of food, depending on what's available, unlike an animal with a more specialized diet. As browsers, their muzzle is more slender and narrow than their grass-eating relatives, and they can pick out high-quality foods such as fruits, seedpods, flowers, leaves, and bark. Spiral-horned antelope have small, low-crowned teeth, and their digestive systems don't process highly fibrous food, such as grass, as well as their cattle relatives.

What a difference gender makes

Spiral-horned antelope bulls tend to be heavier and darker than the cows. In most species, only the bulls have horns; in the few species where cows have horns as well, the bulls' horns are always heavier and longer and often have more spirals. The spirals help the bulls lock horns with each other when engaged in fights over cows.

Family life

Most spiral-horned antelope species live in areas with thicker vegetation and are typically found in smaller groups. These antelope also use the vegetation to hide their newborn calves during the day. The cows “tuck” their newborns away and visit them for nursing, which keeps the calves out of sight from predators such as lions or hyenas. We sometimes call their babies “tuckers.” Babies that are tucked will only come out of hiding when they hear their mother call them to let them know it is time to eat. Every tucker baby knows the sound of its own mother's call.

Meet the species

Bongo Tragelaphus eurycerus

Bongos are found in East Africa's forests. They are typically chestnut red in color; however, males become darker with age until they are almost black. Narrow, vertical white stripes and a reddish coloration may help them become “invisible” in their habitat: red is the first color to disappear in dark or dimly lit settings! Bongos are the largest and heaviest of the antelope that live in forest areas, with bulls measuring up to 4.6 feet (1.4 meters) tall at the shoulder and weighing up to 485 pounds (220 kilograms). They need a good supply of food each day, which is why they live in a habitat that has plenty of herbs, low shrubs, and even bamboo. This is the only species in the Tragelaphus genus in which both bulls and cows have horns.

Greater kudu Tragelaphus strepsiceros

In this species, the bulls are much bigger than the cows, outweighing them by up to 220 pounds (100 kilograms). Greater kudu are commonly found in woodland and hilly areas of eastern, central, and southern Africa. They have vertical, white body stripes on their short, grayish brown coat, white diagonal stripes, called chevrons, between their eyes, and up to three white cheek spots. The cows and calves are redder in color, which gives them better camouflage in their woodland habitat. Greater kudu live in small herds of 3 to 10 cows and their young. Bulls are usually solitary except during the breeding season.

Lesser kudu Tragelaphus imberbis

We are not making a statement about their worth by calling them “lesser kudu,” but are describing their size! Lesser kudu are about half the size of greater kudu. They have a sleek, brownish gray coat with clearly marked vertical white stripes on their bodies, making them very hard to find in the dappled sunlight coming through trees. Lesser kudu also have white chevrons between their eyes with white patches on their neck. They are typically found in thicket vegetation in eastern Africa from Sudan to Tanzania. Lesser kudu are not as social as greater kudu, usually living alone or in pairs, and are most active at night.

Bushbuck Tragelaphus scriptus

The bushbuck is another species that spends time in the water, swimming across shallow streams or ponds. Bushbuck commonly make their homes in deep forest areas. These are the smallest of the spiral-horned antelope at 2 to 3.6 feet (0.6 to 1.1 meters) tall and weighing 53 to 173 pounds (24 to 77 kilograms). They have dark brown to bright chestnut red coats with a white stripe running down the back and white body stripes that can be prominent or broken, or just some faint spots on the haunches. There are a lot of individual and regional differences in coat colors and patterns, and as many as 40 varieties of bushbuck have been described, with those that live in dark forests usually darker in color. Bushbuck are more solitary than other spiral-horned antelope.

Sitatunga Tragelaphus spekii

Sitatungas are one of the smaller species of spiral-horns and are often found in swampy, marshy areas near rivers in central Africa. They have shaggy, slightly oily coats that can be yellowish to dark gray on bulls and lighter and redder in color on cows. Sitatungas have vertical white stripes as well as some spots on their bodies, white patches on the throat, and white cheek spots. Long hooves that splay out help them walk through mud without sinking into the ground. They are very comfortable in water and will often swim to different food sources. Unfortunately, they also live in dense forest areas where they are hunted as bushmeat.

Lowland nyala Tragelaphus angasi

This species is usually found in southeastern Africa near rivers or dense vegetation. Bulls can be multicolored with a shaggy, dark gray-brown coat with faint white, vertical stripes along the sides, a brown neck, orange legs, and white chevrons between the eyes. In addition, long hairs hang from the bull's neck. The cow is much redder with clearly marked white stripes and a shorter coat. Her white chevrons are much thinner and she looks very much like a bushbuck cow. Instead of fighting to establish dominance, the bull uses visual displays, such as raising the hair on his neck and walking with stiff legs.

Mountain nyala Tragelaphus buxtoni

The mountain nyala has a shaggy, grayish brown coat with four barely visible vertical white stripes. It has a white chevron between the eyes, two white spots on the cheeks, two white patches on the neck, and a brown and white crest of hair along the back.

This species was given the “mountain” part of its name due to its highland forest habitat in Ethiopia. In these areas, the native people hunt the animals for their meat and for medicinal purposes. Female mountain nyalas are also hunted for their urine, which is believed to cure syphilis. The lower region of the mountain nyala’s range has thicker vegetation and provides shelter, making it an ideal habitat. Unfortunately for the species, the native people have also found this to be a good area for growing crops and grazing their animals, leaving less room for the nyala. The mountain nyala is currently endangered.

Eland Taurotragus oryx

Eland are social animals that live in herds of 25 to 70 animals. Native to the savanna and woodland habitats of southern, central, and eastern Africa, eland are generally light brown but may turn gray with age. Thin, vertical white stripes on the side are barely visible. Both bulls and cows have horns and dewlaps, although these are much larger on the bulls. Eland are raised like domesticated cattle in parts of Africa for their hide, milk, and meat.

Giant, or Lord Derby's, eland Taurotragus derbianus

As its name suggests, the giant eland is the world's largest species of antelope. Found in the woodlands and savannas of western, central, and eastern Africa, this species is also known as Lord Derby's eland, named in honor of the 13th Earl of Derby, who had a large, private zoo on the grounds of his home in England during the early 19th century. The largest bulls are up to 11 feet (3.4 meters) in length, stand up to 5.9 feet (1.8 meters) at the shoulder, weigh as much as 2,200 pounds (1,000 kilograms), and have horns that may be up to 3.9 feet (1.2 meters) long.

Giant eland are nocturnal. When eating, they use their massive horns to break off branches to reach tasty leaves. Bulls have been seen breaking branches to provide food for the cows and calves! The horns are also handy for digging up thick-leafed plants, melons, bulbs, roots, and onions.

Watch out!

Although the mountain nyala is the only spiral-horned species listed as endangered, the other species are also being hunted in an unsustainable manner for their meat, and some hunters kill the animals simply to take their spiral horns as trophies.