Rhinos do everything slowly, and breeding is no exception. A white rhino cow does not have her first calf until she is six or seven; a bull is not usually able to hold a territory and mate until ten to twelve. Gestation lasts around 16 months. The calf is born weighing 40 to 60 kilograms (35 to 45 for a black rhino), is on its feet within an hour and starts nibbling grass at about two months, although it will suckle for over a year.
Mother and calf stay together for two to four years. A white rhino calf usually walks in front of its mother and copies her every reaction; when she stops, it stops. Only when she is ready to calve again does she push the youngster away. That gives a calving interval of three to four years, so a female might produce eight to ten calves in a long life.
This is why rhino populations recover so slowly from poaching. Even under perfect conditions a rhino population grows by only a few percent a year, and every adult female lost takes a decade of future calves with her.
Sources
Owen-Smith, R.N. 1988. Megaherbivores – The influence of very large body size on ecology. Cambridge Studies in Ecology, Cambridge University Press: 369 pp.
Owen-Smith, R.N. 2024. Megaherbivores. In: Encyclopedia of Biodiversity, 3rd edition, Volume 2. pp. 123-137.
