Providing captive animals with opportunities to display a range of species appropriate behaviours and to make behavioural choices that give them some control over their lives is among the goals of an animal husbandry approach known variously as behavioural enrichment. Enrichment research in both laboratories and zoos has shown the importance of providing animals with an ever changing or rotating array of stimuli and behavioural opportunities (Ben-Ari, 2001). It is important that environmental enrichment encourages natural and not unnatural behaviours.
Enrichment may serve various functions like (1) improving well-being by reducing the levels of abnormal and injurious behaviour, increasing exercise, satisfying behavioural needs and optimizing the level of stimulation that animals receive, (2) educating zoo visitors by increasing the levels of natural and interesting behaviours, visibility and activity levels and (3) conserving endangered species by improving the success of captive breeding and reintroduction programmes. A simple way of behavioural enrichment is variability in enclosure topography and vegetation. Because rhinos can be aggressive towards each other, planting (protected from rhinos), rock piles, dirt mounds and other forms of visual barriers may help ease social tension by partially blocking rhino sightlines. Mud wallows and rubbing posts are other simple enrichment items and are particularly important for skin health (Fouraker and Wagener, 1996).
Designing indoor holding so that each rhino must pass through a common area prior to its individual stall allows rhinos to consistently sniff and mark another’s dung-piles. Within reason, it is recommended that dung piles not be totally removed during cleaning. This again allows rhinos to obtain information about each other using their well-developed olfactory ability. With vet and management approval, dung may be exchanged with other zoos and placed in the rhino enclosure. The novel dung may stimulate sexual activity or increase territory marking behaviour. If the institution houses more than one rhino species or subgroups the same effect may be obtained by exchanging dung in-house (Fouraker and Wagener, 1996).
Rhinos may also benefit from addition of various objects. Enrichment items must be designed with the following criteria in mind:
Can not be swallowed
Can not be torn or ripped
Can not be crushed or broken
Can not trap or entangle the animal
Can not cut, poke or scrape the animal
Objects that can be used as enrichment items:
PVC pipe, spool with treats, barrel, waterbath (pool), moose stool, bamboo contraption, boomerball, bison stool, Logs, hanging boomerball, pronghorn stool, hanging logs, street brush, spinna, sprinkler, stumps, top soil, keg, smashed barrel, browse, rubbing posts, complex enclosure, spool.
Another form of enrichment is having miscellaneous food items hidden in the substrate. By varying the time and location of food this will help to keep the animals occupied. Be sure to hide food on hard surfaces that are covered with mulched branches to avoid ingestion of sand or pebbles while the animals are digging for the hidden items (Gulenschuh and von Houwald, 2002).An old tyre could be used as an enrichment item as well, it should be cut open so that the tire cannot get stuck around the nose, horn or neck of the rhino.