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White rhinoceros is a genus of white rhinoceros in the family Ungulidae
[14]
A mammal. The body is round and strong, the skin is thick and smooth, and the body surface is nearly gray; Head long, incisor and canine teeth degenerate, developed 7 pairs of cheek teeth with a very thick calcareous layer; There are two horns, one big and one small, one front and one back, horns are not bony, but derivatives of epithelial tissue, made up of horny fibers; The shoulders form a raised acromion by developed myeloid spines, which are connected with ligaments to support the head; The limbs are stout and powerful, with three toes on the front and back limbs; The upper lip is flat, wide and square, so it is called broad rhinoceros and square rhinoceros;
[15
]
Males weigh more than females.
[16
]
White rhinos are found in southern and northeastern Africa, living near jungles, grasslands, forests, and plains, occasionally entering steep mountain marshes. When the weather is hot, they are mainly active in the morning and evening, and other times they roll in the mud or rest; When it was cool, he would lie down in the shade and take a nap,
[17
]
Living alone or in small groups, males have territoriality but no strong exclusivity, and females have strong protective behavior. White rhinoceros feeds on grasses. Males reach sexual maturity around age 11 and females around age 7.
[14]
They breed all year round, about 17-18 months of gestation,
[18
]
1 birth every 3 years, 1 child per birth. Life span of nearly 50 years.
[14]
White rhinoceros is the king of the rhinoceros kingdom for its huge size, and among land vertebrates, it is second only to elephants and weighs only to elephants and hippos.
[17
]
Because of its tall and powerful, it is also a "star" ornamental animal in zoos in various countries.
[14]
Overharvesting of rhinos for their horns has decimated white rhino populations,
[16
]
It is classified as near Threatened (NT) on the IUCN Red List of Threatened Species.
[19]
Since then, the white rhino population has increased in many national parks and reserves in Africa through increased conservation and breeding. Recent data put the number of white rhinoceros in the forest at about 6,000.
[16
]
- Chinese name
- White rhinoceros
- Latin name
- Ceratotherium simum
- alias
- White rhinoceros , Rhinoceros quadratus , Latirostris
- Foreign name
- White Rhinoceros
- world
- animalia
- The door
- Chordate phylum
- The outline
- mammalia
- Orders,
- Perissodactyla
- Families,
- rhinocerotidae
- Belong to
- White rhinoceros
- Kind of
- White rhinoceros
- subphyla
- Vertebrate subphyla
- suborder
- Ceratotype
- subclass
- Eutheria
- subspecies
- Southern white rhino, northern white rhino [4]
- Distribution area
- Central, southern and eastern Africa
- Namers and years
- (Burchell, 1817)
The name "white rhinoceros" comes from the Dutch word "weit", meaning "wide" (wide flat), for their wide, flat lips, later mistakenly called "white" (white), so called "white rhinoceros", also known as "square mouth".
[12]
White rhinoceros
Ceratotherium
From the Greek "cerato" meaning "horn" and "thorium" meaning "beast", the species name
simum
From the Greek word simus, meaning "flat nose".
[13]
Adult white rhinoceros weigh between 1,000 and 3,600 kilograms. White rhinoceros has relatively small eyes compared to its body size, square lips, and a long neck with a bulge. They have two different-sized horns. The longer Angle length is 1660 mm. In females, the horns are longer and thinner. The shorter horns can grow up to 550 mm long.
[7]
their
head
The average length of the body (excluding the tail) is 3.35-3.77 meters. White rhinoceros
tail
The average length is 0.57 to 0.77 meters. In addition, the average shoulder height of white rhinoceros ranges from 1.71 to 2.85 meters, while their average girth ranges from 2.01 to 2.20 meters. There are 24 teeth, and the tooth formula is:
incisor
0/0, canine 0/0, premolar 3/3, molar 3/3.
[7]
White rhinoceros skin is pale gray, dense, tough, and has plate-like folds. The epidermis is on average 1 mm thick and the dermis 18 mm thick. White rhinoceros have very tall teeth. In addition, they have flat, wide mouths. White rhinoceros are called "white" not because they are "white", but because their faces are "wide".
[7]
The average weight at birth is 40-60 kg, with a head length of 0.50-0.65 m. The horns of young rhinoceros can only be seen six weeks after birth, when the black membrane covering the horns falls off. White rhinoceros can see their body hair three months after birth.
[7]
Southern white rhinoceros
Ceratotherium simum simum
In contrast, northern white rhinoceros (
Ceratotherium simum Cottoni
) is relatively small in weight and body length. In both subspecies, the female white rhino is slightly smaller than the male. However, there is no quantitative data here on male and female and northern and southern sizes to compare. One feature that distinguishes the two subspecies is their body hair, as the southern white rhinoceros subspecies has less body hair than the northern white rhinoceros subspecies.
[7]
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White rhinoceros
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trait
|
White and black rhinoceros
Diceros bicornis
) Approximate. They are distinguished by the size of their mouths and torsos, not by their skin color. The white rhinoceros has an outward mouth that is square, while the black rhinoceros has an inward mouth that is triangular. White rhinoceros weighs almost twice as much as black rhinoceros, and in addition, white rhinoceros has a distinctive flesh protrude above the back of its neck.
[5]
|
|
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picture
|
White rhinoceros
|
Black rhinoceros
|
Typical habitats for white rhinoceros include dense forests, savannas, and grassy woodlands. White rhinos usually live near water sources, as they usually bathe twice a day. In addition, white rhinos are more commonly found near riverbanks and low-lying areas in the morning. As temperatures rise, they move to more shady areas, such as dense forests or the middle of mountain slopes.
[7]
A common behavior of white rhinoceros is the way they react to predators, for example
Lion
(
Panthera leo
) Attack. For example, all white rhinos run with their back feet constantly touching the ground and their front feet following the direction of the other rhinos. White rhinoceros can run at speeds of up to 24 km/h and for short periods up to 40 km/h. White rhinos are usually non-aggressive animals. However, females with young rhinoceros are more aggressive than males and other females because of their protective effect on young rhinoceros. Other common behaviors include mud bathing in the summer and sand bathing in the winter. White rhinoceros rarely bathe in water.
[7]
White rhinoceros are both diurnal and evocative, which varies from season to season. In winter, they are diurnal, which means their peak activity occurs during the day; In summer, it is mainly in the morning and evening, and the peak time of the activity is 5-9 am and 3-6:30 PM. This shift is a way to avoid hot summer weather.
[7]
The rest of the time, they roll in the mud or rest; When the weather is cool, I lie in the shade and take a nap, and life is very comfortable.
[6]
White rhinoceros do not migrate from one place to another during different seasons. Males sometimes fight for territory. Males that are defeated often migrate to other areas. In addition, males determine boundaries by urinating and will only leave the territory to fetch water. White rhinos rarely share territory with other rhinos.
[7]
The dominant white rhino has its own non-overlapping territories. Males typically range from 0.75 to 13.80 square kilometers, while females range from 6 to 8 square kilometers. White rhinos have a dominant rank, and stronger rhinos have more territorial space. On average, male white rhinoceros actively defend about 0.7-3 square kilometers of territory. Female territories are slightly smaller, averaging 0.5-2.3 km2. White rhinos tend to have a larger range during the dry season because they find it easier to forage during the dry season than during the rainy season.
[7]
White rhinos use several different sounds to communicate. Usually, male white rhinos are louder than females. In addition, when fighting with other male rhinos, males make purring and snorting noises. Females emit a loud bass roar when fighting with other females or against males. If the young don't see their mother, they wheeze, whine, and squeal. White rhinos often make gruff squeaks when chasing or being chased, and their defensive voice is a growl. Males make burping noises when they approach females.
[7]
White rhinos are nearsighted, but they have a strong sense of hearing and smell. Therefore, olfactory communication plays an important role in protecting its territory. In white rhino populations, the dominant males spray their urine to mark the boundaries of their territory. In addition, white rhinos have common dung piles, which makes it easier for rhinos to identify each other within an area. Public dung piles also play a role in mating, as males can determine whether females are ready to mate based on the smell of their feces.
[7]
White rhinoceros are herbivores. They are very greedy, sometimes just eat, 7-8 hours can not move 1000 meters, eat the grass, as if it has been trimmed as neat. White rhinoceros have a habit of defecating in fixed locations, where feces often accumulate in mountains.
[8]
White rhinos don't have many predators. Due to
hyena
(
Crocuta crocuta
In rare fights, some white rhinos lack part of their ears or part of their tail. In addition, some young rhinoceros have been killed by lions (
Panthera leo
) Killing cases. To avoid these potential predators, white rhinos may roam in groups made up of females and juveniles. These groups are common in habitats inhabited by these large carnivores. The main predators of white rhinoceros are humans (Home sapiens), who illegally poach them for their horns.
[7]
Historically, northwestern Uganda, southern Chad, southwestern Sudan,
Central African Republic
Eastern Hoa
Democratic Republic of the Congo
To the northeast is the northern white rhino (
Ceratotherium simum Cottoni
) of its original distribution. Southern white rhinoceros
Ceratotherium simum simum
It is found throughout southern Africa. However, the current range of this subspecies is more limited. Northern white rhinoceros is found only in
Democratic Republic of the Congo
. The southern white rhino is found in
Botswana
,
Namibia
,
Eswatini
,
Zimbabwe
,
Cote d 'Ivoire
,
Kenya
and
Zambia
.
[7]
Distribution map of white rhino
Distribution map of white rhino
-
Mating system
White rhinoceros are polygamous, meaning that both males and females have multiple sexual partners. Male white rhinos are wary of females entering their territory. After the female enters the territory, the male stays with the female for a day to investigate whether she is ready to mate. If the female is ready, then the male will usually follow her for another 3-5 days, during which time the female will respond with snorts and roars. Before mating, pairs last 5-20 days; During this time, if the female tries to enter another male's territory, the male will block the way, and sometimes a confrontation between male and female will occur. However, if the female successfully enters another male's territory, then the previous male will stop following the female.
[7]
Males detect a female's readiness to mate by the smell of her urine; Urine contains chemicals that signal that a female is in heat. Females usually first come into heat at three and a half years of age, but they do not reproduce until they are five years old. Almost all females breed after the age of five. Some of the signs of mating behavior that females give off are frequent urination and whistling. Among males in the same population, fecal testosterone levels were higher in territorial males than in non-territorial males. In addition, territorial males generally spend more time with females and generally have more mating partners than non-territorial males. As a result, territorial males have a higher reproductive success rate than non-territorial males.
[7]
To mate, the male puts both feet on the female's back. Mating lasts an average of 15-30 minutes, with ejaculation every 4-5 minutes. The mating behavior will last 2-5 days because the male's testosterone levels will last 2-5 days. After that, the female leaves the male's territory.
[7]
-
Reproductive characteristics
White rhinos breed throughout the year, but in southern African populations the peak is usually between October and December, and in eastern African populations between February and June. White rhinoceros give birth to one offspring at a time, weighing an average of 48.5 kilograms at birth and doubling in size at six months. Females reach sexual maturity at 3-5 years, while males reach sexual maturity at 5-7 years. Female white rhinoceros can breed between 5 and 46 years of age. White rhinoceros have long breeding intervals of 2.5 to 3 years. This long reproductive interval is associated with a long gestation period of 530-550 days.
[7]
-
postnatal
Young rhinoceros don't start breastfeeding until a few hours after birth, usually for 2-3 minutes at a time. The mother is the sole caregiver of the young, and the male has no parental care for the young except during mating. White rhinoceros begin to graze at 2 months of age, but they are dependent on their mother for nutrients until 6 months after birth. After six months of age, the mother still cares for the children, protecting them from external threats such as predators and wildfires. In addition, young rhinoceros often move in front of their mother early in life and respond immediately when she changes direction. The young usually stay with their mothers for two months. Young rhinoceros usually start weaning at 1 year of age, and white rhinoceros stay with their mother for 2.5 to 3 years. At that point, the mothers drive the young out of their territory and start a new life.
[7]
-
Life span
White rhinoceros have a different lifespan in captivity than in the wild. In the wild, males and females live an average of 46-50 years. The longest recorded life span of a northern white rhino in captivity is 30 years and three months. Similarly, the longest recorded life span of the southern white rhino subspecies in captivity is 30 years. The average life expectancy of white rhinoceros is 39-43 years in the wild and 27-30 years in captivity. However, most rhinos die from human poaching rather than natural causes. Other causes of death for white rhinos include drowning, getting stuck in mud, falling off cliffs, and burning in out-of-control wildfires.
[7]
|
Chinese name
|
Scientific name
|
Namers and years
|
|---|---|---|
|
Southern white rhinoceros
|
Ceratotherium simum simum
|
(Burchell, 1817)
|
|
Northern white rhinoceros
|
Ceratotherium simum cottoni
|
(Lydekker, 1908)
[4]
|
Be included in
Convention on International Trade in Endangered Species of Wild Fauna and Flora
(CITES) - Appendix II.
[2]
As of December 31, 2017, there are an estimated 18,064 white rhinoceros in the wild.
[2]
-
Southern white rhinoceros
Once widespread in the jungles of southern Africa south of the Zambezi River, southern white rhinos had been reduced to a small population of about 20-50 individuals in KwaZulu-Natal, South Africa, by the end of the 19th century and were on the verge of extinction.
[2]
At the time, there were thought to be 2,000 to 3,000 northern white rhinoceros.
[11]
However, by the end of 2012, after years of conservation and multiple translocations, these subspecies had grown to an estimated 21,316 species of wild animals. As poaching increased, the estimated population dropped by about 15 percent to 18,064 individuals by the end of 2017, with a confidence level of 17,212 to 18,915 individuals.
[2]
However, the survival situation of northern and southern white rhinoceros has undergone tremendous changes. While the life of northern white rhinoceros is on the line, under strict and meticulous protection, the number of southern white rhinoceros has recovered to more than 10,800 (IUCN, 2019).
[11]
At the end of 2012, South Africa remained the home base of the subspecies (about 86.5%) with an estimated 18,933 individuals. Smaller reintroduced subpopulations have occurred in the former range countries of Botswana, Namibia, Eswatini and Zimbabwe.
[2]
-
Northern white rhinoceros
Northern white rhino and southern white rhino in
gene
Morphologically, its skull and teeth are different from those of southern white rhinoceros. They once flourished in Uganda, but have since disappeared due to local authorities' lack of protection. In Guaramba
National park
Their numbers reached 35 in the late 1980s and 30 in April 2003, after which six were killed and four were born.
[3]
Poaching and civil war in the Democratic Republic of Congo and neighboring South Sudan have had a devastating impact on the northern white rhino. While poaching pressure initially increased during civil unrest and war in the late 1990s, good breeding has kept the population relatively stable. However, since 2003, poaching has escalated and numbers have declined rapidly, with 11 carcasses found during a three-month period from March to May 2004. The number of confirmed northern white rhinos dropped from 30 in April 2003 to four in August 2005. Despite intensive systematic surveys, no live rhinos have been found since 2006, and no signs of live rhinos have been reported since 2007. It is believed that the northern white rhino may be extinct in the Democratic Republic of Congo. In war-torn South Sudan, there have been rumors that there may be survivors, but so far, there has been no conclusive evidence of a discovery.
[2]
In 2009, four northern white rhinoceros living in Dv's Kralove zoo in the Czech Republic became the only hope of saving the subspecies, and they were sent to Kenya's Oppeyata Wildlife Reserve for artificial conservation in their former place of origin. However, one of the males, named Suni, died in 2014.
[9]
In 2015, Sudan, the world's last surviving male northern white rhino, had his horn removed and was guarded 24 hours a day by four heavily armed police officers in an effort to save the subspecies from extinction.
[9]
On March 20, 2018, Sudan, the world's last male northern white rhino, died in Kenya at the age of 45 (equivalent to 100 human years). The two surviving northern white rhinoceros are Sultan's daughter Najin (27) and granddaughter Fatu (17).
[1]
African governments have been protecting rhino populations in protected areas, such as South Africa
Kruger National Park
Mlierwan Game Reserve in Eswatini, Uganda
Murchison Falls National Park
And Kenyan
Meru National Park
.
[7]
South Africa has at least 20 National parks, one of which, Kruger National Park, is one of the largest nature reserves in Africa, with about 7,000 southern white rhinos living in the park and its surrounding protected areas. Kruger National Park has also set up a number of cameras in the park to better monitor and manage the status of the animals.
[11]
-
North and south white rhinoceros hybrid test tube cattle, embryos after successful breeding by the southern rhino surrogate
Due to the large size of the white rhino, it is difficult to control, the mother's ovary is 1.5 meters below the skin, and it is difficult to take the eggs through the rectum, after all, there are only two single northern white rhinoceros, the research team has previously removed four oocytes in a female northern white rhinoceros that died naturally, but such materials are too precious to use. The researchers first tried to take eggs from southern white rhinos, and eventually the researchers used a 2-meter long ultrasound device to obtain 83 oocytes through multiple follicular perforations through the rectum, and the oocytes needed to undergo two culture divisions to produce the egg cells we know.
[10]
After the cultured oocytes divided into egg cells, the preserved single sperm of the northern white rhinocera was injected into the egg cells, and then electrical stimulation was used to improve the success rate of fertilization, and finally the embryos were cultured in a constant temperature environment of 37.5 degrees. The researchers' efforts eventually yielded results, and finally four North-South hybrid embryos developed to the stage of being transferred to the intrauterine blastocyst. Due to research needs, embryonic stem cell lines were extracted from 2 embryos in order to verify the differentiation ability, and the remaining 2 embryos were frozen for transfer to female southern white rhinoceros for surrogate pregnancy. Whether normal and healthy hybrid northern white rhinoceros could be successfully produced is unknown.
[10]
-
Purebred Northern white rhinoceros in vitro, the embryo is successfully developed by the southern white rhinoceros surrogate
To breed a pure northern white rhino to keep the species alive, sperm and egg cells from the northern white rhino must be used, but punctures of oocytes from two only young can be extremely risky, and a live species can be literally lost.
[10]
The researchers claim to have so far successfully created three embryos, presumably from previously frozen oocytes. The breeding procedure is still being tested as described above, and it is estimated that before the successful creation of a pure northern white rhino, they will first try to create a hybrid white rhino, which is generally not attempted without new technology and financial support.
[10]
-
Continuation of pure northern white rhinoceros
Assuming all goes well, and the southern white rhino that was conceived after artificial in vitro fertilization produces a purebred northern white rhino, the researchers will surely continue to do so until they can reproduce naturally.
[10]
But the new problem is that when they can reproduce naturally, they are all closely related, and inbreeding does not improve, that is, it does not evolve, it only maintains and develops the advantages and disadvantages of the blood line, and it is permanent.
[10]
If you have been inbreeding will only make this shortcoming more and more obvious, once there is basically no solution for a genetic disease, it will only be more and more enlarged, and finally it will be gradually eliminated by nature.
[10]
-
Artificially induced stem cells from frozen northern white rhinoceros
So scientists are trying to use induced pluripotent stem cell technology to stock northern white rhino cells into artificial oocytes and sperm, so that the northern white rhino has a sustainable genetic diversity, the above problem can be solved naturally, and even many endangered animals can use this method to continue in nature.
[10]
Unfortunately, it has not been successful, and there is still a long way to go to study how to make the northern white rhino species can reproduce naturally and return to nature.
[10]
White rhinos are also considered a keystone species because they help increase grass biodiversity and have the potential to prevent wildfires. Waldram et al. (2008) reported that white rhinoceros eating grass makes the grass so short that wildfires cannot burn the grass. In addition, the removal of rhinos from grasslands resulted in the loss of 50 percent of the region's short-grass land cover.
[7]
In addition, white rhinoceros and
Bovine ibis
(
Bubulcus ibis
) and
Starlings with red shoulders
(
Lamprotornis nitens
There is a symbiotic relationship. The birds feed on insects and parasites from the rhino's skin and back. In the beginning,
The red-billed oxpecker
(
Buphagus erythrorhynchus
It is also thought to have a symbiotic relationship with rhinos. However, recent studies have shown that the red-billed oxpecker actually extends the healing time of the wound and removes earwax, rather than feeding and reducing ticks on the rhino's skin.
[7]
