Thomson's Gazelles

Thomson's Gazelles are presented as a test case for interpreting apparently altruistic animal behavior. Their conspicuous leaps in front of predators initially seem to warn companions at personal risk, but the book develops a contrasting possibility: stotting may chiefly advertise an individual gazelle’s fitness to the predator, and thereby serve its own interests rather than the group’s.

The apparent puzzle

In the book’s opening discussion of individual altruism, Thomson's Gazelles are invoked as animals that leap conspicuously in front of a predator. The display resembles a bird’s alarm call: it appears to alert companions while calling the predator’s attention to the animal performing it. This seeming self-endangerment made the behavior a pointed challenge for a theory that explains altruism through the interests of individuals or their genes.

The author returns to the example when examining the claim that group selection is the only explanation for such behavior. The gazelles’ high jumps appear especially difficult to fit into that claim because, unlike bird alarm calls described as discreet, stotting is ostentatious. The display can look almost provocative, as though the leaping animal were inviting the predator’s notice.

A signal aimed at the predator

The proposed alternative, associated with A. Zahavi and foreshadowed by N. Smythe, reverses the apparent direction of the signal. Stotting may be directed primarily at the predator, not at other gazelles. Companions notice it and may respond, but that effect, on this account, is incidental to the display’s primary function.

A high, conspicuous leap can advertise that its performer is fit and healthy and therefore difficult to catch. The book notes that many mammalian predators are known to select prey that seem easy to capture, including old or unhealthy animals. By displaying its ability to jump high, a gazelle may signal that it is neither old nor unhealthy, encouraging the predator to pursue a less impressive neighbor instead.

Implications for altruism and selection

On this interpretation, a display that looks like a warning or sacrifice is not necessarily altruistic. Its apparent benefit to nearby gazelles does not establish that it evolved for the good of the group: the leaping animal may itself benefit by persuading the predator to chase another. The behavior thus turns an apparent act of self-endangerment into a possible form of self-promotion, with the predator as its audience and the neighboring gazelle bearing the displaced risk.

The example illustrates the book’s broader insistence that visible behavior must be distinguished from its evolutionary explanation. Stotting is offered as a proposed account, not as conclusive proof that every display has the same function. Its importance lies in showing how a striking case of apparent altruism can be reconsidered through competing explanations, rather than taken at face value as evidence for group benefit.