Rhino Gestation Period: How Long Are Rhinos Pregnant?

Few animals on Earth command more respect than the rhinoceros. With its horned head, bulky body, and thundering gait, it is truly the master of its world. Its ancient appearance even leads some to wonder if it’s related to dinosaurs. But with rhino populations dwindling at an alarming rate around the world, their reproductive abilities have taken center stage. How many calves can a rhino birth? How long are rhinos pregnant, and how often can they reproduce? Find out all about this majestic animal below!

Types of Rhinos

Rhinos are large, horned mammals that belong to the family Rhinocerotidae. Next to the elephant, they are the second biggest land mammal. There are five species of rhinos living today, all in Africa and Asia. The two African species are the white rhino and the black rhino. The Sumatran, Javan, and Indian rhinos all reside in Southeast Asia. Habitats include grasslands, savannas, shrublands, tropical forests, and deserts. Conservationists classify three of these species as Critically Endangered.

They are herbivores and subsist on plant matter like grasses, leaves, buds, roots, bark, and fruits. Some species need to consume up to 120 pounds of grass a day to survive. To consume this much, they spend many hours grazing and chewing.

With their intimidating size and aggressive temperament, adult rhinos have no natural predators other than humans. Baby rhinos (calves) may also be in danger from large natural predators. Crocodiles, wild dogs, hyenas, and big cats like lions will all attack a vulnerable rhino calf.

Black Rhino (Diceros bicornis)

Black rhinos have dark hides, triangular lips, and small humps on their shoulders. They are the first of the two-horned species. The other two are white rhinos and Sumatran rhinos. Though they remain critically endangered, careful conservation has given them another bid at survival. Conservationists are slowly reintroducing populations of black rhinos to areas they once inhabited, like Rwanda. Only three subspecies remain, as scientists have declared the western black rhino subspecies extinct.

White Rhino (Ceratotherium simum)

The white rhino is the largest of the five species, and males can weigh up to 6,000 pounds. Despite its name, its hide is more gray than white. Its head is so massive that it requires a bulky hump on its shoulders to hold it up. Its lip is broad and square, enabling it to easily graze grass.

White rhinos are divided into two subspecies, the northern and southern white rhinos. The northern white rhino is functionally extinct, meaning that there are no breeding animals left in the wild; only two females remain alive.

Sumatran Rhino (Dicerorhinus sumatrensis)

The Sumatran rhino is the smallest of the five species. It’s also the only one with fur. Scientists believe the Sumatran rhino is the closest living relative of the long-extinct Woolly rhino. Its double horns make it unique among Asian rhinos. There may be as few as 30 individuals left in the wild.

Javan Rhino (Rhinoceros sondaicus)

The Javan rhino is the first rhino species with a single horn. Some females don’t have a horn at all. There are only around 76 of these rhinos left. This rhino is smaller than the Indian rhino but larger than the Sumatran rhino.

Indian Rhino (Rhinoceros unicornis)

Though once on the verge of extinction, the Indian rhino’s numbers have climbed to the point that it is no longer considered a critically endangered species. Instead, it is now classified as Vulnerable on the IUCN Red List.

The Indian rhino is the second species with a single horn. It’s also the second-largest species next to the white rhino. Thick, pliable skin folds give its hide the appearance of plate armor.

Rhino Behaviour

White rhinos are the most social of the five species. Mothers with calves will often group together for increased protection and socialization. The other species tend to be more solitary. Some black rhino individuals are the sole occupants of territories covering up to 100 square kilometers.

Rhinos are naturally aggressive defenders of their territories. They will charge any animal, including another rhino, that they perceive to be intruding. Because their eyesight is poor, they may confuse nonaggressive animals or inanimate objects for genuine threats. They have been known to charge nearby people and vehicles. Despite their size, they can run astonishingly fast. Black rhinos, the fastest of the five, have been known to reach speeds of 34 miles per hour.

Rhino Gestation

Female rhinos are usually ready to mate by five years of age, though they may be sexually mature by the time they are 3.5 years old. To signal their readiness to mate, they whistle, urinate, and defecate. Males leave the females soon after mating.

Rhinos are pregnant for 15 to 16 months, though white rhinos may carry for up to 18 months. Among land mammals, this incredibly long gestation period is second only to that of elephants, which carry their young for 23 months. Due to their extended pregnancies, rhino populations struggle to recover from poaching and disease.

Females ovulate every 28 days and will only mate one or two days out of every cycle. Rhinos usually only have one calf at a time. Although twins are possible, they are extremely rare. Rhino calves can weigh well over 100 pounds at birth and can walk within an hour of birth. Rhino calves are weaned at around 18 months old but remain with their mothers until they are three to four years old.

However, female rhinos only give birth every two to five years. This, combined with their lengthy gestation period, means that populations grow slowly and is one of the main reasons that populations depleted by poaching struggle to recover.