Changing Group Structure
When introducing rhinos it is important to provide auditory, olfactory and visual contact between the individuals. Tactile contact through bars should be provided. Introductions should be made after careful acclimatisation of the animals.
Experienced staff members should always be present for introductions and a plan for separating them should be in place, should this be necessary e.g. high pressure water hose. It may be necessary to keep the animals separately when they are inside at night.
Steps in the introduction process – this applies to all introductions, the animals should be kept separated until step 4.
Animals in the same indoor enclosure or multiple outdoor enclosures should have olfactory and auditory exposure to each other. If the animals are not housed near each other (i.e., enclosures on opposite sides of the zoo, etc.) they should be moved to the same exhibit area.
Animals should be given visual contact with each other in addition to the above sensory modalities. If at any point during this process the animals display symptoms associated with stress (e.g., pacing, diarrhoea, excessive vocalisation) for more than two to three hours, the introduction should return to the previous step.
If animals are not already positioned adjacent to each other, they should be moved closer together (e.g., to adjacent stalls or adjacent outdoor enclosures).
The actual introduction (full tactile exposure) should take place in the largest enclosure available. Preferably, the enclosure should be familiar to the least dominant animal and include ample “run-arounds”.
Within institutions in which rhinos can be left together 24 hours a day, they should be separated during the first several nights or until they show only minor aggression (Fouraker and Wagener, 1996).
Aggression in Black rhinos ranges from ritualised to true aggression. Face-to-face staring is often seen at the beginning stages of ritualised aggression and may be an opportunity for the participants to “size each other up”. Ritualised aggression may subsequently proceed to fencing or sparring and then charging with or without an open mouth threat. Aggression becomes more serious as one animal begins chasing the other, which also include or lead to horn strikes and gores. With this kind of aggression problems arise in small enclosures and in dry moat ditches. Another indicator for aggression is coming into oestrus. Excited animals run with their tail up and very often start to be aggressive (Fouraker and Wagener, 1996).
When introducing more animals together, at first start with the introduction of the females and with the male as the last animal to be introduced.
Introduction of a new female to an established male-female group: Female Black rhinos generally do not tend to form strong pair bonds. Therefore, a new female should be introduced to an established male-female group one individual at a time, but it is not necessary that she is introduced to all females before being introduced to the male (Fouraker and Wagener, 1996).
Introduction of a new male to an established female group: As previously discussed, female Black rhinos do not generally tend to form strong pair bonds. However, if a multiple-female group is established and managers perceive that the females have formed strong bonds, the new male should be introduced to the females as a group rather than to one female at a time. If the females are not compatible, but an introduction is necessary (EEP recommendation, breeding, etc.), the new male should be introduced to each female individually (Fouraker and Wagener, 1996).
Introducing a female to a female: Two females may be kept in the same enclosure depending on the characters of both animals. Initially, the females should be familiarised with the enclosure. The females should have contact through bars when they are indoors. When they no longer show aggression toward each other, the rhinos can be introduced. Close observation is necessary after the introduction.