Predator response

Predators on blackbuck at the Guindy Park Reserve Forest and Point Calimere are three in number: man, stray dogs, and the jackal. Wild pigs also predate on new-born fawns (H. S. H. Hussainy, personal communication). At the Guindy Park Reserve Forest, man as predator has been reduced to a minimum. The only large-scale predator is the stray pariah dog. These are dogs who have lost their masters and who band together and take to deer running. When dogs approach a blackbuck herd, it is the does that first notice them. They at once take the alarm position. That is, they face the predators, ears erect, body stiff, and look straight ahead at the dogs. As these antelopes are gifted with excellent eye sight, predators are often sighted at a long range.

In the Polo Field at Guindy, where responses to dogs have been observed, the does leave the field if the dogs close in. Their flight distance appears to be more than that of the males. The females leave the field properly in line led by a large doe. At this stage, the males do not leave. They stand their ground in their territory in the alarm position. If the dogs approach any closer than 100 – 150 yards, their flight distance, the males one by one turn around and walk off toward the scrub jungle and Government House, that is, the direction taken by the does. Actual chase by dogs of blackbuck have not been seen though kills and attempts at chase have been seen. Cheetal chased by dogs have been seen a few times. Mortality (blackbuck) due to dog predation at the Guindy Park Reserve Forest and IIT is not high. The fact that blackbuck stay in open places and that they are territorial play an important part in this fact. The dogs are more successful with cheetal.

The presence of man in the Polo Field is also acknowledged first by the does. They leave the field one behind the other in the same orderly fashion exactly as they do in the case of dogs. If the man moves closer, the males once again are the last to leave. After the departure of the predator, it is the males that come back first, the females come much later. Sometimes an hour passes before a female can be seen once again on the maidan.

Warning signals

Blackbuck have three types of warning signals that warn not only conspecifics but also other ungulates that happen to be in the immediate vicinity: 1) sneezing, 2) alarm position, and 3) spronking.

Sneezing sounds very much like a human sneeze but is much louder. It is nasal and can be heard from quite a distance. Sneezing is a common auditory signal. On one occasion at Point Calimere, a buck sneezed 35 times on discovering the author behind a shrub.

The alarm position as described earlier constitutes in standing stiff, ears erect, watching the predator’s every move. On occasions while in an alarm position these animals stamp their fore feet. It is presumed that they are depositing scent signals from their inter-digital glands. George Schaller refers to this in his book The Deer and the Tiger when speaking of spronking as we shall see below.

Spronking, or stotting as it is called in African gazelles, is the most important warning signal. This comprises of the animals jumping from one spot with all four feet leaving the ground together, with the rump patch prominently displayed. This spring or jump may be repeated one after another for a considerable time and great distances may be covered. This display is very infectious as it were and will certainly be taken up by all the animals in the herd. Adult territorial males are not given much to this display, though they certainly do if the situation warrants it. Females and sub-adults do so at the slightest provocation. An interesting example was seen in July 1977.

On the evening of 18-7-1977, I was sitting hidden near the Tamil Nadu Forest Department grass feeding spot. Territorial animals ‘A’ and ‘E’ were present. Some cheetal were also feeding at the point.. Buck E suddenly smells or sees me. He spronks away sneezing, followed by A. Although E left the place, A stopped after a while and stoof looking at me. All cheetal stopped feeding, raised their heads and looked at the two bucks. After a while, they resumed feeding. The bucks did not return. These warning signals have interspecific values.

Spronking by itself is a warning signal. It is used as a warning when a predator is noticed. Its use is not only as a visual warning but also as an auditory one. Here is a case in point.

Near the riding club at the Guindy Park Reserve Forest on 26-5-1979, territorial buck “I” and another male with five females was feeding. Suddenly ‘I’ spronked away, perhaps because he spotted me. At the pattering sounds of ‘I”s feet, the other males and does looked up. Then sneeze warning signals were heard. It was not possible to determine the originator of the first signal, but from then on ‘I’ and the other male traded sneezes. Observing along the alrm position of these animals, I glassed the area and found a large jackal approaching the does.

Here, we see sneezing as a warning signal and that spronking has auditory values. Spronking has also been noticed when herds of does and sub-adults enter the Polo Field from behind and suddenly notice the author seated under the tree close by. This normally leads to spronking as a herd. Spronking has also been observed between sub-adults in play fighting.

On 24-4-1979, in the K. K. Tank shores, two sub-adults are play fighting. The animals are in the first years of their life. They clash fairly loudly. At this, one of the sub-adults spronked, as if they are cavorting. They resume their fight. Again, one of them spronks, then they break off the fight.

Discussion

Schaller (1967) comments on spronking that: 1) leaps help the animal to keep the point of the animal in view in high grass, and 2) scent deposits by the inter-digital glands leave an olfactory signal for others passing later (Pocock 1910 cited in Schaller 1967). Stamping of fore feet during the alarm position may have similar scent-marking values. George Schaller (1967) also notes that “the noise of thundering hooves may be an auditory signal to others”.

Estes and Goddard (1967) say that “the stotting displays of the [Gazella] thomsonii in particular is so closely identified with the appearance of wild dogs as to appear specifically adapted to the particular predator’s hunting behaviour.” Walther (1964) hypothesizes that it is an expression of high but not the highest level of excitation. Most likely to appear in transition from high to a low level and vice versa. Its evolution as a warning signal could thus have been derived from tendencies of a gazelle to stot in situations or rising excitation occasioned by the approaching predator. In our observations it seems that the sudden sight or intimation of a dangerous object releases such a display. A sudden release of energy on seeing something fearsome, which manifests itself as spronking. Estes (1967) says “in fact it was only after a wild dog pack moved in to the N’goro that the warning function of the display became clear to me. So seldom had I seen it performed in contest of danger”. Spronking by sub-adults has also been discussed by Estes (1967)” “stotting is annotated not only with danger but also with play fight between fawns and sometimes with intra-specific pursuits by members of both the sexes”.

The sight of someone behind a tree, or excitement during play fight, all these occasions provoke spronking. This release of energy must have had its evolutionary genesis in the fact that presence of predators released a sudden burst of energy ritualized into a warning signal. Blackbuck therefore rely on sight, sound, and pheromones for passing information of potentially dangerous situations to conspecifics.

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