RHINOCEROSES

Indian rhinoceros
Rhinoceroses are the world's second largest land animal after the elephant. The word rhinoceros is derived through Latin from the Ancient Greek rhino ("nose") and keras ("horn"). The plural in English is rhinoceros or rhinoceroses. A group of rhinos is called a "crash" or “herd.” [Sources: Richard Conniff, Smithsonian magazine, November 2011; Wikipedia; Edmond Bradley Martin, National Geographic, March, 1984; Heimanta Raj Mishra and Eric Dinerstein, Smithsonian, September 1987.]
Richard Conniff wrote in Smithsonian magazine, “The peculiar appeal of rhinos is that they seem to have lumbered straight out of the Age of Dinosaurs. They are massive creatures, second only to elephants among modern land animals, with folds of thick flesh that look like protective plating. A white rhino can stand six feet at the shoulders and weigh 6,000 pounds or more, with a horn up to six feet in length, and a slightly shorter one just behind. (“Rhinoceros” means “nose horn.”) Its eyes are dim little poppy seeds low on the sides of its great skull. But the big feathered ears are acutely sensitive, as are its vast snuffling nasal passages. The black rhino is smaller than the white, weighing up to about 3,000 pounds, but it’s more quarrelsome.”
David Attenborough wrote: Some leaf-eaters that moved out on to the plains, however, were altogether too big to find safety in holes. They had to protect themselves in a different way. Some did so by becoming even bigger. The small forest rhinoceroses grew into two- ton monsters with skins so tough that even the claws of a lion or a tiger can make little impression on them. In India, the one- horned rhino developed a skin so thick it is pleated into joints to allow the body within a little movement. On the African savannahs, two different kinds of rhinos evolved, the black and the so- called white. In fact the two species are very similar in colour but the white owes its name to a misunderstanding of the Afrikaans name 'weit'. This refers to the animals 'wide' upper lip, which is very different from that of the slightly smaller black rhino, whose upper lip is prolonged into a mobile point. Well able to take care of themselves and with a need to wander widely in search of the great quantities of grass they must have to sustain their immense bulk, adult rhinos are largely solitary animals. They are also extremely intolerant of company and not only readily charge an approaching human being but one another. Almost a third of female black rhinos and a half of the males die from wounds. [Source: “Life of Mammals” by David Attenborough]
Members of the rhinoceros family are characterized by their large size (all species can reach a weight of one ton or more); their herbivorous diet; small brains; and large horn. There is some debate as to which are larger: hippopotami or rhinoceroses. Hippopotami can weigh as much as four tons (the size of a whale) but average around 3,000 pounds. White rhinoceros, the largest rhino species, weigh up to 4,500 pounds but on average are larger than hippos.
RELATED ARTICLES:
ASIAN RHINOCEROS: SPECIES, HISTORY AND THEIR ENDANGERED, FRAGILE STATUS factsanddetails.com
HUMANS, RHINOCEROS AND RHINO ATTACKS factsanddetails.com ;
INDIAN RHINOCEROSES: CHARACTERISTICS, BEHAVIOR AND COMEBACk factsanddetails.com
JAVAN RHINOCEROS: CHARACTERISTICS, BEHAVIOR, UJUNG KULON factsanddetails.com
ENDANGERED JAVAN RHINOCEROS factsanddetails.com
SUMATRAN RHINOCEROS: CHARACTERISTICS, BEHAVIOR, MATING factsanddetails.com
ENDANGERED SUMATRAN RHINOS: THREATS, GOOD AND BAD NEWS factsanddetails.com
BREEDING ENDANGERED SUMATRAN RHINOS: EFFORTS, SUCCESS, SETBACKS factsanddetails.com
Websites and Resources on Animals: International Rhino Foundation rhinos.org ; Save the Rhino International savetherhino.org; Animal Diversity Web animaldiversity.org ; BBC Earth bbcearth.com; A-Z-Animals.com a-z-animals.com; Live Science Animals livescience.com; Animal Info animalinfo.org ; World Wildlife Fund (WWF) worldwildlife.org the world’s largest independent conservation body; National Geographic National Geographic ; Endangered Animals (IUCN Red List of Threatened Species) iucnredlist.org
Rhinoceroses Species and Numbers
There are five species of rhinoceros: 1) the one-horned Indian rhinoceros in India and Nepal, 2) the one-horned Javan rhinoceroses in Java and previously Southeast Asia, 3) the two-horned Sumatran rhinoceros in Sumatra and previously Borneo, 4) the black rhinoceros in Africa and 5) the white rhinoceros in Africa. The one horned rhinoceros of Asia is the second largest of the five species of rhino. The African white rhino is the largest and the African black rhino is third, followed by the Sumatran rhino and the Javanese rhino.
All species of rhinos are extremely endangered due to overhunting and destruction of their habitat. Humans have hunted rhinos extensively because nearly all parts of the animal have been used in folk medicine. The most prized part of the rhino is its horn, which has been used as an aphrodisiac, fever-reducing drug, dagger handle, and as a potion for detecting poison. /=\
There are only about 27,000 rhinos in the world. Most live in carefully guarded and managed game parks and reserves in South Africa. According to Save the Rhino, as of 2022, there were 16,830 white rhinoceros, 6,470 black rhinoceros, 4,000 Indian rhinoceros, 35 to 50 Sumatran rhinoceros and 76 Javan rhinoceros. South Africa has the largest population with 13,991 white rhinoceros and 2,065 black rhinoceros. India has the second largest population with about 3,260 Indian rhinoceros. Kenya has the third largest population with 1,977 total rhinos, including 1,004 eastern black rhinos, 971 southern white rhinos, and two critically endangered northern white rhinos.
In recent years the population of some species has risen while for others it has declines. In the late 2000s, according to Save the Rhino there were 20,165 white rhinoceros, 4,880 black rhinoceros , 2,850 Indian rhinoceros, 200 Sumatran rhinoceros and 50 Javan rhinoceros. At this time South Africa had 18,563 white rhinoceros and 1,570 black rhinoceros; India had about 2,200 Indian rhinoceros and Kenya had 300 white rhinoceros and 600 black rhinoceros.
Rhinoceros Taxonomy
Rhinoceros belong to the order Perissodactyla (odd-toed ungulates, or a mammal with hooves that feature an odd number of toes), the suborder Ceratomorpha; the superfamily Rhinocerotoidea; and the family Rhinocerotidae. All Rhinos have three toes, and are members of the Family Perissodactyla, which is known as the "odd-toed" ungulates. Rhinoceros is closely related to the extinct genera: Gaindetherium and Punjabitherium /=\
The family Rhinoceroteridae contains living rhinoceroses represented by five species placed in four genera: 1) Rhinoceros (Indian and Javan rhinoceroses, both with one horn), 2) Dicerorhinus (Sumatran rhinoceros, which has two horns), 3) Diceros (black rhinoceros, with two horns) and 4) Ceratotherium (white rhinoceros, with two horns). Rhinoceros is a sister group with Dicerorhinus, according to both molecular and morphological data. It is estimated that Rhinoceros diverged from the other genera approximately 26 million years ago.
According to Animal Diversity Web:. Three of these species are found in south-central Asia and the other two live in Africa south of the Sahara. Rhinoceroses generally inhabit savannahs, shrubby regions and dense forests, and the African species usually live in more open areas than do the Asiatic species. [Source:Liz Ballenger and Phil Myers, Animal Diversity Web (ADW)]
Rhinoceros has always been clearly distinguished as being distantly related from the African genera, Diceros and Ceratotherium, but it was unknown where Dicerorhinus fit in. Only recently was it clarified that Rhinoceros and Dicerorhinus were sister groups. The Family Rhinocerotidae is in the Order Perissodactyla. Family Tapiridae appears to be the sister taxon to Rhinocerotidae. Rhinoceros was originally described by Linnaeus in 1758, and has kept the name since. [Source: Evan Smith, Animal Diversity Web (ADW)]
Early Rhinoceros History
Rhinos are not closely related to any other animals. They belong to one of the oldest mammal families. In many ways they are more similar to the large extinct mammals that roamed the earth millions of years ago than they are to modern mammals. The five living species of rhinoceros fall into three categories. The two African species, the white rhinoceros and the black rhinoceros, belong to the Dicerotini group, which originated in the middle Miocene, about 14.2 million years ago. The species diverged during the early Pliocene (about 5 million years ago).
Liz Ballenger and Phil Myers wrote in Animal Diversity Web: Fossil rhinos are known from the Late Eocene Period (38 million to 33.9 million years ago). A closely related family, Hyracodontidae, produced the largest land mammal to have ever lived, Indricotherium. This rhinoceros is believed to have stood 5.4 meters tall at the shoulder and to have been capable of reaching vegetation over eight meters above the ground. It probably weighed around 30,000 kilograms — over four times the weight of a modern elephant.[Source: Liz Ballenger and Phil Myers, Animal Diversity Web (ADW) /=]

Rhinocerotoids diverged from other perissodactyls by the early Eocene period (56 to 34 million years ago). Fossils of Hyrachyus eximus found in North America date to this period. This small hornless ancestor resembled a tapir or small horse more than a rhino. Three families, sometimes grouped together as the superfamily Rhinocerotoidea, evolved in the late Eocene: Hyracodontidae, Amynodontidae and Rhinocerotidae.
Rhinocerotoids were abundant in North America, Europe, and Africa from the Miocene Period (23 million to 5.3 million years ago) through the Pleistocene Period (2.6 million to 11,700 years ago). Rhino species grazed temperate grasslands and tundra, and many were covered with a thick coat of hair. One of these species, the woolly rhino (Coelodonta), is clearly shown in the cave paintings of early humans. [Source: Liz Ballenger and Phil Myers, Animal Diversity Web (ADW) /=]
Hyracodontidae, also known as 'running rhinos', showed adaptations for speed, and would have looked more like horses than modern rhinos. The smallest hyracodontids were dog-sized; the largest was Indricotherium, believed to be one of the largest land mammals that ever existed. The hornless Indricotherium was almost seven metres high, ten metres long, and weighed as much as 15 tons. Like a giraffe, it ate leaves from trees. The hyracodontids spread across Eurasia from the mid-Eocene to early Miocene. The Amynodontidae, also known as "aquatic rhinos", dispersed across North America and Eurasia, from the late Eocene to early Oligocene. The amynodontids were hippopotamus-like in their ecology and appearance, inhabiting rivers and lakes, and sharing many of the same adaptations to aquatic life as hippos. [Source: Wikipedia]
According to AZ Animals: Incredibly, there is an ancient animal that roamed South America that was incredibly similar to the rhino in size. This creature was actually so common that it is sometimes considered the most common large-hoofed animal in the region! [Source Colby Maxwell, AZ Animals, September 2024]
Evolution of Modern Rhinoceros Species
The family of all modern rhinoceros, the Rhinocerotidae, first appeared in the Late Eocene in Eurasia. The earliest members of Rhinocerotidae were small and numerous; at least 26 genera lived in Eurasia and North America until a wave of extinctions in the middle Oligocene wiped out most of the smaller species. However, several independent lineages survived. Menoceras, a pig-sized rhinoceros, had two horns side-by-side. The North American Teleoceras had short legs, a barrel chest and lived until about 5 million years ago. The last rhinos in the Americas became extinct during the Pliocene.
There are two living Rhinocerotini species, the Indian rhinoceros and the Javan rhinoceros, which diverged from one another about 10 million years ago. The Sumatran rhinoceros is the only surviving representative of the most primitive group, the Dicerorhinini, which emerged in the Miocene (about 20 million years ago). The extinct woolly rhinoceros of northern Europe and Asia was also a member of this tribe.
Modern rhinos are believed to have began dispersal from Asia during the Miocene. Two species survived the most recent period of glaciation and inhabited Europe as recently as 10,000 years ago: the woolly rhinoceros and Elasmotherium. The woolly rhinoceros appeared in China around 1 million years ago and first arrived in Europe around 600,000 years ago. It reappeared 200,000 years ago, alongside the woolly mammoth, and became numerous. Eventually it was hunted to extinction by early humans. Elasmotherium, also known as the giant rhinoceros, survived through the middle Pleistocene: it was two meters tall, five meters long and weighed around five tons, with a single enormous horn, hypsodont teeth and long legs for running.
Of the extant rhinoceros species, the Sumatran rhino is the most archaic, first emerging more than 15 million years ago. The Sumatran rhino was closely related to the woolly rhinoceros, but not to the other modern species. The Indian rhino and Javan rhino are closely related and form a more recent lineage of Asian rhino. The ancestors of early Indian and Javan rhino diverged 2 to 4 million years ago. The origin of the two living African rhinos can be traced back to the late Miocene species Ceratotherium neumayri. The lineages containing the living species diverged by the early Pliocene (1.5 million years ago), when Diceros praecox, the likely ancestor of the black rhinoceros, appears in the fossil record. The black and white rhinoceros remain so closely related that they can still mate and successfully produce offspring.
See Separate Articles WOOLLY RHINOS europe.factsanddetails.com
African Rhinos

rhino sizes
White rhinoceroses weigh up to 4,500 pounds and stand six feet at the shoulder (males: 168 centimeters, females: 152 centimeters). They are dived into two subspecies: the northern, which has been virtually wiped out in its home range in Uganda and the Sudan; and the southern, which has made a come back in South Africa. White rhinos are not named after color. "White" is a corruption of "”weit”, Afrikaans for wide, a reference to the animals wide lips. But black rhinos ironically were named after their color to distinguish them from white rhinos.
White rhinos are heavier and more placid than black rhinos . They have broad square muzzle and prefer open country, where they crop grass. Their exposure in open country made them easy to spot and kill. White rhinos are remarkably non-aggressive. It is possible to drive a vehicle within a couple feet of them, or approach them on foot, at an equally close range, and they won't even bat an eyelash. The mainly feed on grass which they pluck a few blades at a time with their broad, squareish upper lip.
The main difference between black and white rhinos is the shape of their mouths - white rhinos have broad flat lips for grazing, whereas black rhinos have long pointed lips for eating foliage. A subspecific hybrid white rhino was bred at the Zoological Garden Dvur Kralove in the Czech Republic in 1977. Interspecific hybridisation of black and white rhinoceros has also been confirmed. While the black rhinoceros has 84 chromosomes, all other rhinoceros species have 82 chromosomes.
The black rhinoceros weighs 3000 pounds and stands nearly five feet at the shoulder (males: 152 centimeters, females: 137 centimeters) . They are more aggressive than white rhinos and have been known to charge trains that broached their territory. Black rhinos can reach speeds of 35 miles per hour, and turn and change directions incredible fast. The are sometimes hard to see in the wild because the rest in the shade during the daytime and hang it scrubby bush country.
Black rhinos eat mostly shrubs, herbs and fruit, but hardly any grass. They have constantly rotating ears, inch-thick hide and a pointed upper lip and a overlapping lower lip, which allows the animal to grasp twigs and leaves. If there is enough moisture in their food they can go several weeks without water. They enjoy wallowing in the dust and mud. They have the habit of stomping in their own dung to leave odor trails across the savannah, making it easier for other rhinos to find their whereabouts.
Rhinoceros Characteristics
Rhinos have thick armourlike hid, a bright pink underside and relatively tiny three-toed hooves. Their thick protective skin, which is 1.5 to five centimeters cm thick, is formed from layers of collagen positioned in a lattice structure. Their brains are relatively small for mammals (400 to 600 grams). Rhinoceroses have a long life span. They generally live to of 30 to 35 years. It is not unusual for an animal to reach the age of 40.
Rhinos have massive bodies and a large head with one or two horns. Liz Ballenger and Phil Myers wrote in Animal Diversity Web: The horns are dermal in origin; they are very solid and are composed of compressed, fibrous keratin. Rhinos have a broad chest and short, stumpy legs. The radius/ulna and tibia/fibula are only slightly moveable, but they are well-developed and separate. Both hind and forefeet are mesaxonic with three digits each; each digit with a small hoof. Rhinos have small eyes and fairly short but prominent and erect ears. Their thick skin is scantily-haired and wrinkled, furrowed or pleated, producing the appearance of riveted armor plates in some species. The tail bears stiff bristles. [Source: Liz Ballenger and Phil Myers, Animal Diversity Web (ADW) /=]
Rhinos have an elongate skull, which is elevated posteriorly. They have a small braincase, and the nasal bones project forward freely and may extend beyond and above the premaxillae. The surface of the nasals where the horns sit is roughened. There is a strongly developed occipital crest. Rhinos have 24-34 teeth, mostly premolars and molars for grinding (dental formula 1-2/0-1, 0/1-1, 3-4/3-4, 3/3). The canines and incisors are vestigial except for the lower incisors in Asian rhinos, which are developed into powerful slashing tusks. In grazing rhinos (Ceratotherium), the cheek teeth are hypsodont, but they are brachydont in the other genera. Cheek teeth of all species have prominent transverse lophs of enamel. /=\
Rhinos have poor eyesight and are extremely nearsighted. They have been known to charge tree trunks. A charging rhino can reach speeds of 35 miles per hour (compared to 70 mph for a cheetah and 9 mph for a chicken). Rhinos are odd-toed ungulates with three toes. In some species three toes in useful in securing oneself on slippery ground.
Rhinos have powerful lips, adapted for feeding on both long and short grasses. When rhinos are fed apples by hand their tender pink upper lip gently takes the fruit out of one's hands. They often suck the entire hand in their feeder inside their mouths, and it can take some to effort to get the hand back. Rhinos don't have incisors so if your hand get sucked in get it out before it reaches the molars. Their method of digestion of Asian rhinoceros is thought to be similar to tapirs (See Tapirs).
Rhino Horns

Both African species and the Sumatran rhinoceros have two horns, while the Indian and Javan rhinoceros have a single horn. A 19th century description of Indian rhinoceros explains that the horn "projects, not infrequently 30 inches upwards. So long as the animal is quiet, this appendage lies loose between the nostrils, but when excited, the muscular tension is so great that it becomes immovably fixed, and can be darted into a tree to the depth of several inches."
A rhinoceros’s horn is not made out of bone, rather it is composed matted hair and fibrous keratin, the same horny substance found in fingernails, human hair and lizard scales. It has been said that Asian people who take rhino horn for a folk medicine could obtain the same results from swallowing hair trimmings or chewing their fingernails. If a rhinoceros loses its horn, the horn grows back at a rate of about three inches a year.
On the purpose of rhinos horns, SOS Rhino says on its website: “The horns are very well developed in the two species in Africa (black and white rhinos), but much smaller in the three species in Asia (Sumatran with 2 very small horns, Indian and Javan with one horn). The Asian species certainly do not use the horns to fight or to defend themselves, they use their incisors (sharp front teeth for the purpose). The horns have come about in evolution and they had (have) a general function to impress members of the opposite sex. Horns are also used for digging in waterbeds to find water, or to uproot shrubs etc. Some rhinos use the horn to guide their offspring. This is generally the front horn, the second horn does not have a very specific purpose at the moment. We suppose that they had some purpose in the course of evolution.”
Rhino Behavior
Rhinos are sedentary, largely solitary animals. If the have enough forage and water they do little but graze, drink and wallow in the mud. Rhinos require large territories. When a rhino marks its territory it can shoot a spray of urine five meters backwards. All rhinos are generally restricted to areas where a daily trip to water is possible. Rhinos often wallow and bathe in the heat of the day. This is important both for thermoregulation and for avoiding flies.
Liz Ballenger and Phil Myers wrote in Animal Diversity Web: African rhinos tend to feed low to the ground whereas Asian rhinos usually browse on leaves. Both Asian and African rhinos are more active in the evening, through the night and in early morning, spending their days resting in heavy cover. Members of both groups are herbivores, but they may feed primarily on grasses or on branches, depending on the species. Rhinos sleep in both standing and laying positions and are fond of wallowing in muddy pools and sandy riverbeds. They penetrate dense thickets by shear force, often leaving behind a trail that other animals later use. Rhinos run with a cumbersome motion, reaching top speed at a canter. They can, however, attain speeds of up to 45 kilometers per hour for short distances. [Source: Liz Ballenger and Phil Myers, Animal Diversity Web (ADW) /=]
Rhinoceroses are basically solitary and territorial, except for the mother-child unit. Groups of adult cows or bachelor bulls are sometimes formed, however, and during the mating season pairs of rhinos may stay together for up to four months. Rhinos mark their territories with urine and by dropping their dung in well-defined piles that can reach up to one meters in height. They often furrow the areas around these piles with their horns, making the piles even more conspicuous. /=\
Like elephants, hippos, water buffalo and other sparsely-hair, rhinoceros like to wallow in water holes or mud holes to moisturize their skin, cool off and remove parasites. During the monsoon season the rhino spend up to eight hours a day wallowing in the mud. They can sometimes be seen in pools of water covered with hyacinth, which the animals feed on. Rhinos frequent the same mud pits, or wallows, over the course of their life, where they roll on the ground to smear their bodies with wet soil to keep ticks away. Sometimes rhinos look like they are covered in flour. This a result of taking a sod or dust bath.
Rhinos make a strange huffing sound when running away from danger. Baby rhinos cry "miya, miya" when they want their mothers. Sometimes near-sighted rhinos mistake elephants for their mothers. When alarmed rhinos charge. They have been known to charge trees and jeeps.
Aggressive Rhino Behavior

Rhinoceroses, particularly black rhinos, are known for their aggressiveness and grumpy disposition. A group of rhinos isn’t called a “crash” for nothing. While rhinos rarely fight with other animals they often fight with themselves. Males go after each other when they seek a female in estrus. During the mating season even females go after one another and bulls have on occasions charged calves.
In general, African rhinos are more aggressive than Asian species. Asian forms fight with their bottom teeth (slashing) whereas African species fight with their horns, using them to toss and gore their adversaries. Describing a charge by an Indian rhino, Geoffrey Ward wrote in National Geographic, "A cow concerned for her calf and agitated by the sound of the jeep...suddenly whirled, kicking up dust, and charged straight for us. Sharma...clapped his hands and shouted to warn her off, she kept coming, amazingly fast, her broad body seeming to float above the ground, the head high, ears straining to make out the sources of the annoying sound---Mrs. Magoo at full tilt...We pulled away. She lost track of us, slowed sniffed the air, and went back to grazing."
According to journalist Esmond Bradley Martin when a black charges its head sways “back and forth menacingly, making a thunderous noise each time its feet hit the ground and snorting loudly. Your only thought is how to escape. Usually that means climbing a tree, but many of us are around to tell about charges simply because a black rhino became distracted from the attack by something else at the last moment, or because it had intended only an intimidating mock charge in the first place.”
Black rhinos have a reputation for being very unpredictable. They have been known to charge trees and jeeps. Some animals have been observed walked into camp sites at night scattered smoldering logs of a fire, and then walked away peacefully. One explanation for their erratic behavior is that they have terrible eyesight and may perceive something as a threat when it actually isn't. Jed Bird, a 27-year-old rhino capture officer in South Africa in charge of watching over black rhinos there, told Smithsonian magazine, “The first time I saw one I was a 4-year-old in this park. We were in a boat, and it charged the boat. That’s how aggressive they can be.” Bird makes his living keeping tabs on the park’s black rhinos and sometimes works by helicopter to catch them for relocation to other protected areas. “They’ll charge helicopters,” he said. “They’ll be running and then after a while, they’ll say, “Bugger this,” and they’ll turn around and run toward you. You can see them actually lift off their front feet as they try to have a go at the helicopter.” [Source: Richard Conniff, Smithsonian magazine, November 2011]
Poop Piles: a Major Form of Rhino Communication
Rhinos socialize by sniffing feces at a communal latrine, a study published January 11, 2017 in Proceedings of the Royal Society B says. Carrie Arnold wrote in National Geographic: Chemical clues in white rhino feces provide information about age, sex, general health, and reproductive status to other rhinos that visit the communal latrine, also called a midden, a new study found. “We think of dung as just a waste product, but it’s really a good way for animals to communicate. There’s a lot of information there that we haven’t taken advantage of,” says study leader Courtney Marneweck, an ecology Ph.D. student at the University of KwaZulu-Natal in South Africa. [Source: Carrie Arnold, National Geographic, January 10, 2017
Lots of animals can detect chemicals in urine and feces to learn what's going on with other members of their species. That’s why, for instance, dogs constantly sniff the fire hydrant. What makes white rhinos different from a sniffing Fido is that rhino groups defecate in the same location. Other species get their gossip from middens — especially mammals that live in large social groups like gazelles, monkeys, and rabbits — but the study is the first time the behavior has been confirmed in rhinos.

Marneweck and colleagues tracked more than 200 individual white rhinos in South Africa from different populations and took samples of their poop after the animals visited their middens. This allowed the team to track exactly what individual contributed the sample. Finding the middens was easy, since the hefty mammals trample grass along well-used paths and don’t travel far when nature calls. What's more, at 65 feet across, middens are "huge and hard to miss,” Marneweck says. (Surprisingly, she adds, middens don’t smell that bad: Rhino dung is mostly desiccated grass.)
The scientists then analyzed the chemical makeup of the rhinos' dung. They found that feces of various ages and sexes — such as young animals, dominant males, and females in estrus — carry different chemical cues. Then, the scientists created fake poop from grass and mud and spritzed it with the same compounds found in the dung of these three different groups. They deposited this imposter dung in randomly selected middens and observed how dominant males responded to it.The team found the males were very responsive to the fake dung that carried chemicals from females ready to mate. These males spent more time sniffing it than did other rhinos, visited the midden more frequently, and defecated on top of the experimental poop. This reaction shows that the male rhinos were gathering information from chemicals in the dung, Marneweck says.
Middens provide many benefits to a group of animals, says Madlen Ziege, a Ph.D. student at the University of Frankfurt in Germany. “It’s important that all members in a group are aware of what’s going on. If you know everyone's status, you don’t need to look for them or start fighting,” she says. They’re also important for communicating between separate populations of the same species. Many middens, for instance, sit at the edge of a group’s territory and help reinforce its boundaries, according to Ziege.
Feeding Rhinos and Their Food
Rhinoceroses are browsers. They feed on aquatic plants, shrubs, grass, trees, twigs and branches of low bushes and when available crops from farmer's fields.. Rhinos in captivity love watermelon. Veterinarians often put medicine in watermelons.
Rhinos generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter, if necessary. Unlike other perissodactyls, the two African species of rhinoceros lack teeth at the front of their mouths, relying instead on their powerful premolar and molar teeth to grind up plant food.
Rhinos eat primarily at night, in the early mornings and in the late afternoons. They sleep during the heat of the afternoon. Rhinos are choosy about the kinds of grasses they eat. In some cases they eat grass and deposit seeds near the river banks where they wallow, thereby ensuring supplies of the grasses they like.
Rhinos in India and Nepal are very fond of eating the potato-like fruit of trewia trees. The seeds are deposited by rhinos on river banks, an ideal place of them to grow. B.D. Loutit noted the rhino feed on a plant with "formidable spines and highly irritating latex." It appears the rhino are "able to overcome some major chemical and physical defenses of plants without apparent harm.”
Rhinoceros are non-ruminant herbivores. According to Animal Digestion by S. Sydenham and R. Thomas, For non-ruminants the “fermentation takes place further down their digestive system. This means that by the time the tough walls of the plant cells are broken down, the food has already gone past the part of the gut that absorbs most nutrients. This means that they have to eat huge quantities in order to get enough nutrition. Non-ruminants pass quite a lot of undigested food out of their bodies. They have to spend about three quarters of the day feeding.
Mating Rhinos and Their Young

Female rhinos give birth every two years to a single calf, which is active soon after birth and remains with the mother until the next offspring is born. Gestation is 420-570 days. Sexual maturity is reached at 7-10 years for bulls and 4-6 years for cows. Males will fight aggressively and make a frightful roaring sound during the rut which occurs non seasonly and sporadically.
Before mating a female rhino often charges her mates for several hours to size him up and make sure he is worthy enough to bear her children. She usually initiates sex. The penis of a one ton male rhino is only about two feet long. Sex often last for an hour and half or more, with the male sometimes ejaculating every 10 minutes.
At birth a calf weighs around 75 pounds and can walk within a couple hours. A calf accompanies its mother for two years. Rhino milk has two thirds te calories of human milk and only 0.2 percent fat, one of the lowest of any species. Young rhinos and horses get their energy from sugars rather fat. In contrast hooded seal milk is 61 percent fat, with about 1,400 calories in an eight ounce glass. A mother may tend her calf for up to four years after birth.
Rhinos and Other Animals
No predator except man will go after an adult rhinoceros. In Africa hyenas, crocodiles, lions, wild dogs and leopards will sometimes dispatch baby rhinos. Rhinos usually back down before confronting an elephant. Trained elephants that have never seen a rhino before trumpet and run for the trees when faced with a charging rhino. Young male elephants at Pilanesberg National Park and Hluhluwee-Umfolozi Park in South Africa have been observed knocking over young rhinos and going after them with their tusks.
In South Africa’s Pilanesberg National Park, 18 white rhinos were gored to death by young bull elephants. Why? Some scientists believed it was because the bulls were removed from their group at an early age and had no mature males to discipline. They came into musth and took out their aggression on the rhinos. Naturalist Douglas Chadwick witnessed a female rhino with a calf challenge an elephant over rights to a drinking spot at a water hole. The rhino stamped , snorted and made a bluff rush, he said, adding: "The elephant — a young male — fortunately called her bluff by reaching his trunk into the water and proceeded to hose down the apoplectic mother rhino."
Egrets and myna birds often hang out on the backs of rhinos feeding on insects that make their home in the thick armourlike hide. Frogs like to sunbathe on the back of rhinos in Nepal.
Image Sources: Wikimedia Commons Text Sources: Animal Diversity Web animaldiversity.org ; National Geographic, Live Science, Natural History magazine, David Attenborough books, New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Discover magazine, The New Yorker, Time, Reuters, Associated Press, AFP, Lonely Planet Guides, Wikipedia, The Guardian, Top Secret Animal Attack Files website and various books and other publications.
Last updated December 2024