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| Location: |
World |
| Subject: |
Behaviour - Social Behaviour |
| Species: |
Black Rhino |
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Numerous black rhinoceros (Diceros bicornis (L.)) Vocalizations have been mentioned in the literature in recent years. As described by various authors, these Vocalizations vary considerably from 'mews' and 'squeaks' to 'grunts', 'squeals', 'roars' and 'puffing snorts'.
One additional vocalization was described by Ritchie (1963) as 'like a man trying to get his breath after receiving a violent blow on the solar plexus'. He described this utterance as occurring 'only when approaching a water hole' and probably 'evoked by pleasurable anticipation'. He also suggested that it may be a mating call. We heard a vocalization similar (or identical?) to this, but in a very different situation.
On 17th November, 1966 we immobilized an adult female black rhinoceros and her 10-month-old female calf in Ngorongoro caldera, Tanzania. By nightfall the adult had recovered sufficiently from the drugs to be concerned about the absence of her calf, which was still partially immobilized and tending to wander away. At 2020 h when the calf and adult were 110 m apart, a 'breathing' call was heard at the rate of 7/min. The calf became attentive, listened to the call, and then walked toward the adult and rejoined her within 4 min. By 2044h the calf had again wandered away, but returned when the adult repeated the 'breathing' calls. This time the calls were at rate of 10/min, but the interval between calls varied from 3 to 11 sec. During the following 2 h the calf repeatedly wandered away from its mother and each time the adult made the 'breathing' call continually from the time she noticed her calf's absence until it rejoined her. In general. when the distance of separation was about 100 m, the adult uttered about 8 calls/min until the calf returned. Upon rejoining, the adult's calling ceased. At 2245 h the distance between calf and adult was only 10 m. but the adult again made three 'breathing' calls and they both walked toward each other. The calf was never heard making the calling sound. When the separation was more than 10 m the adult moved but little, and the calf made the sole effort to return in response to its mother's call.
The night was cloudy and moonless. By periodic use of the Land Rover headlights we were able to observe the movements of the pair. The adult appeared to have full control of her senses, and briefly reacted to the sight of her shadow whenever the Land Rover lights shone on her. Unless she heard the 'breathing' call, the calf never had sufficient awareness to realize that she should remain close by her mother.
At 2100 h, a spotted hyaena (Crocuta crocuta (Erxleben)) began annoying the calf, and the calf charged it twice while the adult stood motionless. By 2140 h, eight hyaenas were snapping at the calf's tail and left hind leg. Both adult and calf actively wandered in circles, but failed to remain continuously together. The calf was becoming slightly bloodied by the attacking hyaenas, so we interceded and drove off the hyaenas. Apparently, with more time, the hyaenas could easily have killed the calf. We continued to watch the rhinos into the night until they were fully recovered and far from the territory of the hyaena clan. The pair were observed completely recovered one week later.
The 'breathing' call of the adult rhino sounded very much like the sound produced when a human exhales very forcibly through his nostrils; it resembled the sound of a very deep sigh. Initially. we considered that the call was merely an anomalous respiratory condition of the adult, possibly resulting from the effect of the drugs, and this possibility cannot be ignored. However, the irregularity with which the call occurred, the calf's response to it, and its immediate cessation when the calf approached the adult, suggest that it was indeed a call.
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Black rhinoceros vocalisations
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