Rhinos are impressive animals. After the elephant, they are the largest land animals that roam the world. The only question is how long can they be admired in the wild on earth? Because of its horn it is often attacked by poachers. These useless confrontations make the rhinoceros one of the most endangered species. Another reason they are in danger of extinction is that captive breeding is difficult. How did that happen? How does natural reproduction proceed? And how does the male impress the female?
Black rhinoceros
Mating ritual
When a rhinoceros sees a female in heat nearby, it tries to impress her by walking back and forth. He will also disperse urine and scrape his horn on the ground. Rhinos do not roam in groups and prefer to live in isolation. So when there is a rutting female in their area and another male rhino wants to take his chance, they will attempt to chase each other away. They will do this by sniffing loudly. They keep their heads down and their ears flat. With their feet they will dig up the ground and provoke false attacks. In addition to sniffing loudly, they often also growl and squeak. One will not quickly engage in a real fight.
The female decides!
The female will decide whether to mate. Often males are aggressively rejected. If the female nevertheless wants to mate and a successful fertilization takes place, the gestation period lasts approximately 15 to 16 months. A female only gives birth to 1 calf every two to five years. In addition to poaching, slow reproduction is another reason why the rhinoceros is an endangered species.
The calf
Growth of the rhinoceros
The baby rhinoceros can stand upright after 10 minutes, even if it is not really stable yet. The young are therefore always following their mother who protects them against attacks from other animals. The calf is already eating solid food during the first month. The calf drinks water after four or five months. The young stays with its mother until it is fully grown and a new calf is born. However, the calf is suckled for a full year.
Sexually mature
The calf itself is sexually mature after four years. Some do not reach sexual maturity until after seven years. However, males have to wait 10 years to mate because only then are they strong enough to mate.
The white or black rhinoceros: differences
The white rhino mating ritual lasts about a week. After fertilization of the white rhino it takes 16 months for the young to be born. While the black rhino eats solid food after just one month, the white rhino eats two months. The white rhino also runs in front of the mother and not behind the mother as with the black rhino. After two to three years, the young are chased away because they are old enough to be independent.
Problems with reproduction?
Captivity
In captivity, white rhinos are more difficult to breed. This is thought to be related to the aging process that is accelerated during captivity. Because the females are fertilized less quickly or regularly, this will affect the cycles.
Researchers have already discovered that social interaction also plays a role in reproduction. The situation in that area is completely different in the wild than in captivity. In the wild, male rhinos often live alone and female rhinos in groups of two to three. They never stay with two for more than a month in that small group. This means that there are a lot of changing social contacts. In captivity, however, the animals always live in the same group for a long period of time. The choice of partner is greatly reduced as a result, and so is the chances of reproduction.
Sufficient variety: a necessity!
It is therefore very important in breeding that there is sufficient choice and variety for the male animal. So in each group there must be at least one male and several female rhinos. The areas in which they live in the zoo must also be large enough and imitate their natural environment as closely as possible if one is to increase the chances of reproduction. Stress could also be a reason why reproduction is difficult in captivity. The possible role of nutrition in this problem is also being investigated.