Facts About Gnus (Wildebeests)
Wildebeests, or gnus, are the largest species of antelope.
Credit: Chad Rosenthal

Gnus, or wildebeests, are large African antelopes. Gnus (pronounced like "news") are closely related to cattle, goats and sheep. These animals look like thin, muscular cows with large, sloping backs, curved horns and striped bodies. They also have manes and bushy beards.

Wildebeest is an Afrikaans name that means "wild beast." Gnu is a derivation of the name used by native Africans. The names are used interchangeably. A gathering of gnus is called a herd. However, James Lipton (of "Inside the Actors Studio" fame) coined the phrase "implausibility of gnus" in his 1968 book "An Exultation of Larks." He didn't explain what he meant. The term caught on, and according to the Terms of Venery blog, there have been at least 63 published works that use the phrase.

Gnus are the largest of all antelopes. There are two species, black wildebeests and blue wildebeests. Blue wildebeests weigh 260 to 595 lbs. (118 to 270 kilograms) and are about 4 feet (123 centimeters) in length, according to the University of Michigan's Animal Diversity Web (ADW). The blue gnu, also called common wildebeest, has dark vertical stripes on the shoulders and back. 

The black wildebeest, also called the white-tailed gnu, weighs 242 to 346 lbs. (110–157 kg) and grows to about 6.5 feet (2 m) in length and 3.6 to 4 feet (111 to 121 cm) tall. As the name indicates, black gnus are dark brown to black in color.

Both males and female gnus grow horns, which are typically 18 to 31 in (45 to 78 cm) long, according to National Geographic

Gnus are found in one very specific spot on Earth: southern and eastern Africa, from Kenya to Namibia, according to the ADW. They prefer savannahs and plains, but they can be found in a variety of habitats, including dense bush and open woodland flood plains. The largest populations are found in the Serengeti in Tanzania and Kenya. 

The blue wildebeest (<em>Connochaetes taurinus</em>), a large antelope, can be found in the plains and woods of Southern and East Africa. The <a href="http://www.livescience.com/13550-grazing-animals-shaped-human-evolution.html">blue wildebeest</a> gets its name from the silvery blue sheen of its hide, and it has shaggy tufts of hair on its head and down its back. It&#39;s capable of reaching speeds of 50 mph (80 kph).
The blue wildebeest (Connochaetes taurinus), a large antelope, can be found in the plains and woods of Southern and East Africa. The blue wildebeest gets its name from the silvery blue sheen of its hide, and it has shaggy tufts of hair on its head and down its back. It's capable of reaching speeds of 50 mph (80 kph).
Credit: Federicoriz Dreamstime

Gnu herds are constantly on the search for food and are active day and night. They communicate through sight and smell, but are also very vocal. Blue wildebeest males can bellow loud enough that the sound travels up to 1.24 miles (2 kilometers), according to the ADW. 

As territorial creatures, gnu herds have a certain area they call their own. An average herd's territory encompasses almost 1 square mile (1.5 square kilometers).

Gnus are herbivores and only eat vegetation. They prefer grass, but when grass is hard to find they will also eat leaves. During mating season, males do not sleep or eat while sexually active females are nearby. 

When the rainy season ends in the plains, herds migrate to the savannahs, where there is plenty of water and food. This migration usually takes place in May or June. Around 1.2 million wildebeests join hundreds of thousands of other animals, including zebras and gazelles, in the world's largest terrestrial migration, according to National Geographic. The migrating herds may travel hundreds of miles to find food.

During this migration, about 6,250 gnus, or 0.5 percent of the total herd, drown while crossing the Mara River. However, there is a silver lining to these deaths: The decaying bodies feed local scavengers, including vultures and fish, and leave behind nutrients and minerals in the ecosystem, according to a study published in 2017 in the journal Proceedings of the National Academy of Sciences.

"It is the equivalent biomass of 10 blue whales dropped into the river," study senior researcher David Post, a professor of ecology and evolutionary biology at Yale University, said in a statement.  

After a gestation of eight to eight and a half months, and at the beginning of the rainy season, 500,000 baby gnus are born in February and March each year, according to National Geographic. These babies are called calves, and they are quite large. Calves can weigh 44 to 49 lbs. (20 to 22 kg) at birth.

Calves learn to walk within minutes of birth and in a few days they are part of the herd, walking alongside their mother. It takes the mother six to nine months to wean her young. At 16 months to 76 months, young gnus are ready to mate and can live to around 20 years old.

Wildebeests and zebras cross the Serengeti Plain in an annual migration.
Wildebeests and zebras cross the Serengeti Plain in an annual migration.
Credit: EastVillage Images shutterstock

Here is the taxonomy of the gnu (wildebeest), according to the Integrated Taxonomic Information System (ITIS):

Kingdom: Animalia
Subkingdom: Bilateria
Infrakingdom: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclass: Tetrapoda
Class: Mammalia
Subclass: Theria
Infraclass: Eutheria
Order: Artiodactyla
Family: Bovidae
Subfamily: Alcelaphinae
Genus: Connochaetes
Species: Connochaetes gnou (black wildebeest), Connochaetes taurinus (common wildebeest)
Subspecies: Connochaetes taurinus mearnsi (Western white-bearded wildebeest), (Connochaetes taurinus albojubatus (Eastern white-bearded wildebeest), Connochaetes taurinus johnstoni (Nyassa wildebeest), Connochaetes taurinus cooksoni (Cookson's wildebeest) and Connochaetes taurinus taurinus (blue wildebeest).

According to the International Union for Conservation of Nature (IUCN), neither the black nor the common wildebeest are endangered. The population of the black wildebeest is increasing, while the population of the common wildebeest is stable.

Gnu are a food source for spotted hyenas, lions, cheetahs and African wild dogs.

When faced with predators, gnu herds are very protective. Members will bunch together, stamp, sound alarm calls and will even chase predators. 

Additional resources

Editor's Note: This reference article was first published on April 14, 2016, and was updated on June 26, 2017.