Don’t Call My Bluff: Aggression in Musth Elephants

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A male forest elephant in Dzanga Bai, Central African Republic. The dark streak mid-way between the eye and ear is due due to temporal gland secretions during musth. ©Ana Verahrami

Being able to call one’s bluff is a useful survival tool in the wild, with the stakes being better mates and hierarchical positions. A male elephant will signal aggressive behavior by walking towards another male — head held high and ears flaring outwards. This aggressive behavior may be ritualized or true, that is the elephant may have true intentions to fight or this can merely be an intimidation tactic. Depending on the opponent’s interpretation, a fight may escalate or dissipate. An interesting scenario of the abovementioned paradigm has been observed when a male elephant in musth challenges a larger, non-musth male elephant.

A male elephant reaches a period of musth around the age of 25 years during which aggression and sexuality are heightened for some weeks up to a few months¹. This is due to elevated testosterone levels, found in some cases to have jumped 50-fold². With an increase in testosterone comes more daring and risqué behavior; small musth males will blatantly walk towards larger, normally higher-ranking non-musth males with their ears flared and head held high. Upon seeing these threats, the larger, normally higher-ranking non-musth elephants do not hold their territory or try to scare off the smaller elephants but have been observed fleeing several kilometers¹. The elephants in poorer condition appeared to be the winners. Poole and her team observed Savanna elephants for 14 years, and within these years, only 31 challenges escalated into actual fights. When escalated into a physical fight, smaller musth males retracted their announcements of aggression and retreated³. They had been bluffing, with the intention of winning over females rather than fighting.

This scenario was somewhat shocking to field researchers, who sought to explain the outcome. Why were larger, more threatening elephants retreating from their smaller challengers (who, in fact, were bluffing)? Shouldn’t it have been the other way around? Several researchers tried to explain this behavior with a business perspective. As early as 1974, G.A. Parker termed the phrase “assessment theory” in which elephants adjusted their own behavior after accounting for the costs and benefits of a fight⁴. Poole used game theory when explaining how elephants consider their choices and outcomes based on the possible actions of their challenger (bluffing or not)¹. Ultimately, the winner is decided by his period of sexuality rather than body size. Elephants in musth place a higher value on winning, as they are in a period of increased sexual receptivity. Field data have shown that musth males are the most active and most likely to mate with females, where females prefer mating with musth males over non-musth males¹. Since fights often lead to injury or death, the cost could be a reduction in future reproductive potential and fitness in non-musth males. For those in non-musth, it is therefore not an ideal or beneficial time to win a fight. They are better off waiting.

With this business framework in mind, the outcomes of these challenges seem logical. Yet this framework is complex; it requires that all the costs and benefits at every interaction are taken into account. Field research indicates some kind of higher cognitive awareness in elephants, where they must deduce whether or not their opponent is in musth, in relation to their own period of sexuality. Perhaps an enhanced state of aggression is detected in musth elephants, thus decreasing the probability of their bluffing, or perhaps the costs outweigh the benefits of a fight in non-musth males. This trend of larger, normally higher ranking non-musth males retreating occurred frequently and does not seem by chance. It is difficult to determine cognitive processes of animals, but there is certainly an appreciation for how elephants adapt their behavior to circumstance.

Works Cited

¹Poole, J. H. (1989). Announcing intent: the aggressive state of. anim. behavior, 37, 140–152.

²Hall-Martin, A. J. (1987). Role of musth in the reproductive strategy of the African elephant (Loxodonta africana). South African Journal of Science, 83, 616–620.

³Smith, J. M. (1982). Evolution and the theory of games. Cambridge university press.

⁴Parker, G. A. (1974). Assessment strategy and the evolution of fighting behaviour. Journal of theoretical Biology, 47, 223–243.

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