The recommendation is to build for 2.3 animals, with a minimum of six indoor enclosures. If the building is being phased the initial build must be for at least 1.2 animals with a minimum of four indoor enclosures. These indoor enclosures should be adjacent to and interconnected with each other allowing flexibility to combine enclosures to create fewer larger areas or split them to provide individual areas for each of the three adults and potential calves / juvenile. Adjacent enclosures should be accessible through at least two gates, giving the animals the possibility to roam without danger of being trapped.
At least one of these areas should be suitable for the isolation of an animal (e.g. new animals or sick animals). This area should be off show to zoo visitors, protected from disturbance (such as noise) and should not allow direct contact between animals.
The boundary between the indoor enclosures separating the rhinos from each other should generally be solid walls with an area in the boundary to allow visual and limited physical contact between the animals. These have proved very useful in getting individuals used to each other prior to mixing and to allow keepers to better evaluate when animals are in oestrus using behavioural cues. The isolation pen should be of all solid walls and not allow contact between the animals.
The boundary between the rhinos and the keepers may be solid or bars. Bars have the advantage of giving the keepers an opportunity to habituate the animals to be touched all over their bodies. This facilitates health examinations and veterinary treatments, provides good opportunities for operant conditioning (training) and also promotes a good bond between keepers and rhinos.
Facilities should be designed so that each rhino can be checked over or trained on a daily basis should this be required. It is preferable that these training or examination areas are inside or undercover, however some collections do make use of outdoor training areas (either in addition or instead of indoor areas) to good effect.
Walls are usually made of concrete, concrete clad with wood, or wood of a suitable strength. Wood cladding on the concrete walls may help to prevent the rhinos from excessively rubbing their horns.
Bars are usually vertical, however horizontal and diagonal steel may also be used with great care taken to ensure that the bars are far enough apart to reduce the chance of rhinos trapping their horns and damaging them. Additional barriers may need to be required at low level when housing young calves to prevent them passing through. Vertical bars should be spaced 25 – 30 cm apart.
Enclosure gates will often be the weakest points of the exhibit and therefore adequate hinge and lock strengths are very important. Interior doors are usually constructed of heavy-gauge galvanized steel or pipe that is hinged or sliding. Manual sliding gates are preferred to swing gates or hydraulic gates both for their speed of closure and to reduce the chance of keepers getting trapped or injured.
Gates should be constructed to allow keepers to open and close them without entering rhino space. It is also important that keepers have good visibility either side of the gates in order to operate them safely. When sliding gates are used, the track must be kept clean in order to reduce the chance of them seizing, and care should be taken in the construction of the track to avoid injuring the feet of the animals as they run through gates during introductions. All gates must be firmly secured and designed so the animals cannot dislodge them with their horns, i.e. constructed in a way that the gate cannot be lifted off its hinges by a rhino.