White rhinoceros

The white rhinoceros, also known as the white rhino or square-lipped rhinoceros (Ceratotherium simum), is the largest living species of rhinoceros and the most social of all rhino species. It has a wide mouth made for grazing on grass. There are two types of white rhinoceros: the southern white rhinoceros, with about 17,464 individuals living in the wild as of the end of 2023, and the northern white rhinoceros.

The northern white rhinoceros is critically endangered and very close to disappearing forever. The last known male, named Sudan, passed away in March 2018, leaving only a few females in captivity.

Both types of white rhinoceros face serious dangers, mainly from poaching for their horns and habitat loss. These threats have put the species as a whole into a conservation status of Near Threatened.

White rhinoceroses are also very fast. They can run up to 40 mph (64 km/h) for very short bursts and can keep up speeds of around 30–31 mph (48–50 km/h) for longer periods. They have good stamina and can keep going for a while.

Naming

The name "white rhinoceros" might have come from a misunderstanding. Long ago, Dutch speakers called the rhino "wijd", which means "wide" — referring to its broad mouth. English speakers may have thought "wijd" meant "white", leading to the name we use today. Later, Dutch speakers began using the term "white rhino" from English, even though "wijd" was never written down to describe the animal.

Another name for this animal is the square-lipped rhinoceros, though it is used less often.

The scientific name, Ceratotherium, was given by a scientist named John Edward Gray in 1868. It comes from Greek words for "horn" and "beast". The name simum also comes from Greek and means "flat-nosed", describing the rhino's wide snout.

Taxonomy and evolution

Scientists used to think the modern white rhinoceros came from an ancient species called Ceratotherium praecox. But newer studies suggest this might not be right. Some believe the white rhino evolved from a different ancient species over millions of years.

There are different ideas about how white rhinos developed. Some scientists think they came from an ancient species in Africa that later spread and changed over time.

Southern white rhinoceros

Main article: Southern white rhinoceros

As of the end of 2023, there were about 17,464 southern white rhinos living in the wild. They are the most common rhinoceros subspecies. Most of them live in South Africa. Smaller groups have been placed in countries like Namibia, Botswana, Zimbabwe, Uganda, and Eswatini. They have also been introduced to Kenya and Zambia.

Northern white rhinoceros

Main article: Northern white rhinoceros

The northern white rhinoceros is in big trouble. There are very few left, and they might not exist in the wild anymore. This type of rhino used to live in several African countries south of the Sahara.

In 2009, four northern white rhinos were moved to Ol Pejeta Conservancy in Kenya to try to help them reproduce. But the group kept getting smaller. The last male rhino, Sudan, passed away in 2018 due to old age. Now, only two females, Najin and Fatu, remain at Ol Pejeta. Scientists are working hard to see if they can use stored samples to help these rhinos have babies, but it is very difficult. Some scientists think the northern white rhino should be called a different species, but not everyone agrees.

Description

The white rhinoceros is the largest of all living rhino species and one of the biggest megafauna around. Only the three types of elephant are usually heavier. White rhinos have big, strong bodies and large heads with short necks.

Males are bigger than females, with males measuring about 3.7 to 4 meters long and weighing between 2,000 and 2,300 kilograms. Females are smaller, about 3.35 to 3.65 meters long and weighing around 1,600 to 1,700 kilograms. They have two large horn-like structures on their noses made of a tough material called keratin, which is also in human hair and fingernails. The front horn can be up to 166 centimeters long.

White rhinos have broad, square mouths perfect for eating grass. They don't see very well but have excellent hearing and smell, with big ears that move and very large nostrils. Their thick skin often gets muddy, giving it various colors, and they have very little hair besides some on their ears and tail. Their strong legs end in wide feet with three toes to help them walk on different lands.

Genome

The white rhinoceros has a special set of instructions inside its cells called a genome. For the southern white rhinoceros, this genome is about 2.58 billion base pairs long. Each of their cells has 82 small pieces called chromosomes, made up of 40 pairs that are the same in both males and females, and one pair that determines if the animal is male or female.

Behavior and ecology

White rhinos are special grazers that mainly eat grass and live in grasslands and savannas. They love to eat and spend much of their day feeding, resting, and doing other activities. They like to play in mud to keep their skin healthy and cool. Because they are so big, white rhinos help shape the land where they live, which is important for many other animals.

White rhinos talk to each other using different sounds like calls, grunts, and bellows. They can run very fast, up to 64 kilometers per hour. They usually live in groups of females and their babies, while males often live alone and mark their areas with dung and urine. When males want to mate, they follow the females closely and make loud noises. Females become ready to have babies around six to seven years old, and males around ten to twelve years old. After about 16 months, a female gives birth to one baby, who stays close to her for protection. Baby rhinos can stand soon after birth but are wobbly at first. Adult rhinos live about 40 to 50 years and are safe from most predators because of their size, though very sick adults can sometimes be attacked.

Distribution

The southern white rhinoceros lives mostly in Southern Africa. This group of rhinos almost disappeared in the early 1900s, but has grown strongly since then. By the end of 2023, there were about 17,464 of them living in the wild. Most live in South Africa, with others in Namibia, Botswana, Zimbabwe, and Kenya.

The northern white rhinoceros is in big trouble. It used to live in several countries in East and Central Africa but is now close to disappearing. The last wild ones were seen in Garamba National Park in the Democratic Republic of the Congo. Sadly, many were lost because people took them for their horn.

Both types of white rhinos face dangers from losing their homes and from people taking them for their horn, which is sometimes used in old medicines or as a decoration.

Poaching

White rhinos face a big danger from people who hunt them for their horns. This happens because some people believe that rhino horn can help with health problems, even though there is no proof it works. Rhino horn is made of the same material as human hair and nails.

Because rhino horn is very valuable, some groups work together to hunt rhinos. They use special tools and sometimes even helicopters to find and hunt them. This has made it very hard to protect rhinos, especially in places where there is conflict or danger.

In recent years, the number of rhinos being hunted has gone up a lot. For example, in South Africa, where many rhinos live, the number of hunting cases almost doubled in one year. This has caused the rhino population to drop quickly. Even in zoos, rhinos have been hurt by hunters looking for their horns.

Even with efforts to stop hunting, the high value of rhino horn keeps encouraging people to hunt them. The horn can be worth as much as gold, and hunters continue to find new ways to track rhinos using technology like social media.

Modern conservation tactics

The northern white rhinoceros is in big trouble, with only two females left in the world, both living in captivity. Scientists are working very hard to save this subspecies. In 2009, they moved these two females from a zoo in the Czech Republic to a wildlife area in Kenya, hoping a better environment might help them have babies naturally.

Unfortunately, this didn’t work. In 2014, they tried putting a male from the southern white rhinoceros with the females to see if they might breed, but this also didn’t succeed. Recently, scientists have turned to special lab techniques to help. In 2019, they were able to create embryos from the eggs of the two females using stored sperm from males who have passed away. These embryos are frozen and will be placed into female southern white rhinoceroses in the future, hoping they will grow into new northern white rhinoceros calves.

In captivity

Most white rhinos kept in zoos and wildlife parks around the world are southern white rhinos. In 2021, there were over 1,000 of them in captivity. These rhinos can have babies in captivity if they have enough space, good food, and other rhinos around.

For the northern white rhinos, the San Diego Zoo Safari Park in California, United States, helped try to protect them. Two northern white rhinos, Angalifu and Nola, lived there but passed away in 2014 and 2015. Only two northern white rhinos, Najin and Fatu, are left. They live at the Ol Pejeta Conservancy in Kenya and are watched closely to keep them safe.