Black Rhino have a 15.4-month gestation period, and calves weigh 30-40 kg at birth. The interval between calves varies widely, depending on the age of the female and the nutritional conditions in her habitat. Under good habitat conditions and at populations densities below carrying capacity, most females can produce several consecutive calves at 2 - 2.5 year intervals. Where conditions are less favourable, the average inter-calving interval exceeds 3 years. In many such cases, a calf may be conceived but is lost as the pregnancy nears full term, or shortly after birth. Old females (28 years plus) have difficulty regaining body condition after weaning each calf, and tend to have longer intervals between calves.

The intrinsic rate of population increase in black rhino is around 9% per year. However rhino areas stocked below habitat carrying capacity, or where food conditions are good, and where the population has more adult females than adult males, can commonly achieve average population growth rates of 10-15% per year. In populations exceeding habitat carrying capacity densities or in deteriorating habitats or bad droughts, mortality rates can exceed 4% annually (involving mainly infants and sub-adult rhinos), and female inter-calving intervals lengthen, resulting in little or no population growth.

Black rhino can live in a wide range of habitats, including deserts,semi-deserts, wooded savannahs, woodlands, forests and even sub-alpine heathlands (e.g. up to 3,700 m on Mt Kenya in the past). They survive well  where annual rainfalls are very low  (100 mm/year) to quite high) 1,300 mm per year) . The densities at which Black Rhino can exist in these habitats varies over 100-fold, from less than 1 rhino per 100 km2 in the desert plains of Namibia to more than 1 rhino per 1 km2 in the best thicket and pristine Lerai forest vegetation of East Africa.

Rhino are water-dependent in the majority of habitats, and rhino home ranges are arranged relative to permanent water sources in an area. Rhino can however move a fair distance from water within in their range and in succulent vegetation can live without surface water for a great many months.

Black rhino are territorial, and dominant males will establish territories  with minimal overlap with other dominant males. Younger, subordinate males are tolerated while still  with their mothers  and while they show subordinate behaviour.  They will often have to fight to claim a territory, and often live at the edge of rhino society until strong enough to challenge the established bulls. Female and young black rhino live in small family groups within a home range which can overlap that of other groups and dominant males.

The territory or home range sizes of black rhino in an area do vary, but average range size is mainly dependent on the abundance of suitable food and water availability, and thereafter the area’s rainfall, soil fertility and topography features. For example in thickets range sizes can be as small as as 1 km2, but in deserts ranges can exceed 200 km2

Desert

Succulent Thicket

There is no doubt that black rhino are dangerous wild animals. They have a reputation for being aggressive, short-tempered and unpredictable, and there are one or two cases each year people being charged and injured. They can reach speeds of 55 km per hour, and can turn surprisingly quickly. Generally however they are peaceful and highly curious animals, so they react more out of strong caution, protectiveness of their calf, or fear when disturbed by humans. They will usually try to run AWAY, but will charge if the perceived threat is too near.

Photo courtesy of Richard Adcock, Photographer.[Website: http://Richardadcock.co.za]

Black Rhino are browsers, meaning they eat primarily woody plants and herbs, not grasses. Over 100 different species may be eaten during the year, but in most areas 80% of the diet is commonly made up from around 10 plant species. Young plants of <2m are preferred.   The importance of key plant species to black rhino means that they are vulnerable to habitat changes which impact such plants, including severe fire regimes, vegetation succession (growing too tall and change of species dominance to less palatable species); and high densities of competing browsing species such as impala, nyala, elephant, especially in fenced areas.   The characteristic pruning action of  the black rhino’s bite can be seen on the left-hand Acacia in this photo.