Sacrifice or Betrayal? Scientific Explanations for Stotting in Thomson’s Gazelles

“In the long history of humankind (and animal kind, too) those who learned to collaborate and improvise most effectively have prevailed.” ― Charles Darwin


It was understood for some time that stotting—a stiff hopping movement made by a Thomson’s Gazelle just before it flees its predator, a move that exposes it to the predator, slows it down and delays its escape—was a sacrificial act committed in the face of death. Stotting was viewed as a warning to the herd, issued at the individual’s expense to increase the herd’s overall chance of survival: “undoubtedly a warning signal, it spread wave-like in advance of the pack [of hunting wolves]. Apparently in response to the Stotting, practically every gazelle in sight fled the immediate vicinity” (Estes 63). It would appear from this account that the stotting gazelle is endangering its own life to preserve the lives of others of its species. Not so, says Richard Dawkins in his book The Selfish Gene. He quotes A. Zahavi’s study to explain that stotting is, in fact, an act of betrayal towards the herd: “far from being a signal to the other gazelles, [stotting] is really aimed at the predators…. Translated roughly into English it means: ‘Look how high I can jump, I am obviously such a fit and healthy gazelle, you can’t catch me, you would be much wiser to try and catch my neighbor who is not jumping so high!’” (Dawkins 171).

This paper reviews competing philosophies in the literature concerning stotting—taking into account both theoretical hypotheses and claims backed by evidence from field study—and concludes that stotting is neither an act of altruism nor a selfish act; in fact, with the exception of a mother defending its fawn, stotting can be seen as a more or less indifferent act towards members of the same species. Interestingly, our various attempts to locate a moral basis (when in fact there is none) for this vexing and ambiguous phenomenon reveals something of our own mind, and that has the potential to inform our approach to cultural practice such as art and architecture.

Description of Stotting

Walther portrays the background of quiet serenity in the African plains. Packs of lions and other predators cause little disturbance in the herds of the gazelles. An attack is like a swift storm: “‘The flash goes down’ - one is killed, the others had an escape, peace returns and life goes on” (185).

A tommy, as the Thomson’s Gazelle is known in East Africa, avoids the predator’s approach simply by looking around. While grazing, an individual tommy may keep its head down for up to a quarter of an hour; this is not dangerous in a large herd because there is a good chance that another member of the herd has its head up during that time (Walther 185).

Once a Tommy spots a predator it “erects its neck, puts its ears forward, lowers its croup, and tenses its muscles” (Walther 186). Other movements of alarm include a soft snort of warning, and sometimes compact herds diligently follow the predator at a distance to prevent a surprise attack. Stotting occurs when the attack is initiated from beyond a minimum distance:
With front and hind legs stiffly stretched downward the gazelle bounces up springing from the pastern joints (a). The right and left front leg are close together, and so are the hind legs. In a very long stotting jump the hind legs can paddle a little bit in the air, but usually they are kept more or less in the same position as the front legs (b). During the jump all four legs are brought forward slightly so that in landing front and hind legs touch the ground at about the same time (c). Then, often the animal jumps again in the same manner, and so a chain of stotting actions results. (Walther 194)

In 1967, Estes and Goddard present the first analysis on stotting in Thomson’s Gazelles as part of their paper on the hunting behavior of the wild African dog. Noting that stotting slows down the gazelle, making it more vulnerable, they conclude that it is “hard to see any advantage to the individual in Stotting when chased, since individuals that made no display at all might be thought to have a better chance of surviving and reproducing” (Estes 64). In 1970, Walther gives a detailed description of stotting in the Thomson’s Gazelle (or Tommy) based on a study conducted in Serengeti National Park, Tanzania. He explains that stotting is a means to confuse the attacking animal: “each dog pursued first one, then another tommy, got neither and became exhausted. Finally, all the gazelles had disappeared and the dogs stood alone in the field with their tongues hanging out” (Walther 196).

In 1970, Smythe makes the argument that stotting is a way to engage the predator into a chase before the predator gets too close: “potential prey animals may actually gain an advantage from advertising their whereabouts to potential predators as conspicuously as possible, with the object of inducing the predators to attack” (Smythe 491). In the same year Robert Ardrey argues for a classic case of suicidal sacrifice on the part of the individual: “a local population, in its capacity to surmount the hazards of its habitat for hundreds or thousands of generations, achieves a kind of immortality denied the individual” (197). All of these papers depict the act of stotting as one in which the individual is endangering its life, most likely as part of a collaborative strategy to preserve the community.


In the 70s, we see a shift in this thinking. In 1976, Richard Dawkins quotes Ardrey’s statement to state that—based on A. Zahavi’s study—he believes that the opposite is true. According to Dawkins, an act of altruism is “one that looks, superficially, as if it must tend to make the altruist more likely (however slightly) to die, and the recipient more likely to survive. It turns out on closer inspection that acts of apparent altruism are really selfishness in disguise” (Dawkins 4). Dawkins argues that stotting is a display of strength to the predator: because many mammals choose the old and the unhealthy to pursue, “an individual who jumps high is advertizing, in an exaggerated way, the fact that he is neither old nor unhealthy” (Dawkins 171).

In 1979, Pitcher puts forth the hypothesis that stotting may be a strategy to pause and gain a better view in the case of an ambush. By allowing the gazelle to locate other members of the hunting pack, in this case lions or cheetahs, stotting could be a practical method of planning an escape route (Pitcher 454). In 1980, Coblentz argues against Smythe’s theory of stotting as a strategy to induce an attack, providing reasons why this is not beneficial to the individual. Concern during this decade seems to have shifted from the survival of the species to the perseverance of the individual.


Biological literature in the 80’s no longer argues whether stotting is altruistic or selfish toward members of the same species; it argues instead that stotting is disinterested as far as fellow members of the herd are concerned. In 1986, Caro summarizes eleven hypotheses regarding stotting put forth thus far, and claims to disprove all but two. Additionally, on two accounts, Caro renders the problem of stotting less interesting than it used to be: (1) stotting, he claims, “was found to have a negligible time cost in slow flights and it was normally shown in safe situations when prey were unlikely to be captured;” and (2) “there was no evidence to show that, once a chase occurred, stotting gazelles were caught more or less often than gazelles that did not stott” (Caro 663). Caro dismisses hypotheses concerning “prey signalling its health; startling or confusing the predator; group cohesion; anti-ambush behaviour; play in young animals; warning of conspecifics; and pursuit invitation or deterrence” and supports two hypotheses: stotting informs the predator that it has been detected and it informs the mother that the fawn needs help (663).

Interestingly, Fitzgibbon and Fanshawe’s study of 1988 revives and proves the validity of a few of these “disproved” hypotheses, proving the benefits of stotting during a chase both to the individual gazelle and to the species: most notably, “during hunts, gazelles that wild dogs selected stotted at lower rates than those they did not select. In addition, those which were chased, but which outran the predators, were more likely to stot, and stotted for longer durations, than those which were chased and killed” (Fitzgibbon 69). They conclude that “stotting could be an honest signal of a gazelle's ability to outrun predators, which coursers take into account when selecting prey” (69). By distinguishing responses to different kinds of predators, they were able to produce more coherent and convincing results: “results suggested that gazelles were far more likely to stot in response to coursing predators, such as wild dogs, than they were to stalking predators, such as cheetahs” (69). This makes sense because wild dogs rush towards gazelles from a distance and there is adequate time to stot. Cheetahs often sneak up on gazelles and initiate the attack from a much closer distance, leaving little opportunity to stot.

Fitzgibbon et al. proved that stotting is inter- and not intra-species communication, and it is an honest (perhaps involuntary) signal to the predator that the predator takes into account before selecting its target.


Over the years, in the various analyses attempting to unravel this simple yet enigmatic movement made by a grazing animal just before its final chase to death, a movement that defies the logic of self-defense and swift escape, a movement that could hint at a basic desire to collaborate or betray, we see reflected our own hopes and fears as we wonder what stotting could mean for human interactions when faced with adversity.
In the introduction to his book, Dawkins issues a dire warning to the reader: “be warned that if you wish, as I do, to build a society in which individuals cooperate generously and unselfishly towards a common good, you can expect little help from biological nature” (Dawkins 3). It is not difficult to see how his reading of stotting as an individual’s act of betrayal might have been driven by a desire to produce this coherent narrative: that we are born selfish but through learning we can collaborate.

Writing six years earlier, Robert Ardrey is making a case for an innate desire to collaborate by way of social contracts. His book is called The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder and in it he cites the case of the tommy to argue that “any genetic change, whether or not of benefit to the short-lived members, if of benefit to the survival of the group should spread inevitably to become a part of the whole gene pool” (Ardrey 197).

We do find a human application of stotting in Steven Pinker’s book How the Mind Works. Pinker uses Dawkin’s reading of stotting—a handicap that is developed precisely to advertize the strength of the animal to its predator—to “prove” his point about conspicuous consumption:
Conspicuous consumption is counterintuitive because squandering wealth can only reduce it, bringing the squanderer down to the level of his or her rivals. But it works when other people’s esteem is useful enough to pay for and when not all the wealth or earning power is sacrificed…. Only the healthiest animals could afford to [stot, a move that] consumes nutrients, hinders movement, and attracts predators. (Pinker 500)

In our complicated contemporary culture, Pinker argues, these shows of handicap or vulnerability by the very strong or wealthy include hipness, or the adoption by the upper classes of styles of the lower classes, in order to “differentiate themselves from the middle classes” (Pinker 502).  He argues that this “thirst for status in the form of hipness drives the worlds of art, architecture, and the politics of the cultural elite” (Pinker 502).

It matters little then whether the tommy’s goal is to distinguish itself from other gazelles that are less well off in terms of health, in order to avoid being eaten. It matters that its behavior signals a handicap to us, and on it we can project the struggles of our own existence. In the end, as Fitzgibbon et al. have argued, stotting is neither a sacrificial move nor one inspired by intra-species intrigue. It is likely to be a disinterested, involuntary sign of fear, a clear communication to the predator that it has been detected and that it shouldn’t expect too easy a chase.

 “The universe we observe has precisely the properties we would expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind pitiless indifference.” ― Charles Darwin



Caro, T.M. “The functions of stotting: a review of the hypotheses.” Animal Behaviour 34.3 (June 1986): 649–662.
Caro, T.M. “The functions of stotting in Thomson's gazelles: some tests of the predictions.” Animal Behaviour 34.3 (June 1986): 663–684.
Coblentz, Bruce E. “On the Improbability of Pursuit Invitation Signals in Mammals.” The American Naturalist 115.3 (March 1980): 438-442.
Dawkins, Richard. The Selfish Gene. Oxford: Oxford University Press, 1976.
Estes, Richard D. and John Goddard. “Prey Selection and Hunting Behavior of the African Wild Dog.” The Journal of Wildlife Management 31.1 (January 1967): 52-70.
FitzGibbon, C. D. and J. H. Fanshawe. “Stotting in Thomson's gazelles: An Honest Signal of Condition.” Behavioral Ecology and Sociobiology 23.2 (1988): 69-74.
Pinker, Steven. How the mind works. New York: Norton, 1997.
Pitcher, Tony. “He Who Hesitates, Lives. Is Stotting Antiambush Behavior?” The American Naturalist 113.3 (March 1979): 453-456.
Smythe, N. “On the Existence of ‘Pursuit Invitation’ Signals in Mammals.” The American Naturalist 104.939 (September - October 1970): 491-494.
Stankowich, Theodore and Richard G. Coss. “Effects of risk assessment, predator behavior, and habitat on escape behavior in Columbian black-tailed deer.” Behavioral Ecology 18.2: 358-367.
Walther, Fritz R. “Flight Behaviour and Avoidance of Predators in Thomson's Gazelle (Gazella Thomsoni Guenther 1884).” Behaviour 34.3 (1969): 184-221.

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