A year scaring buffaloes and gazelles to understand the 'friendships' of the savannah

It's the classic image of the nature documentary: zebras, wildebeests, antelopes and other herbivores grazing quietly on the African savannah when, suddenly, a stealthy fierce throws itself at full-time time. The on-call lioness has cast an eye on one of them, the helpless wildebeest breeding or the desapered gazelle, among all the possible victims of this tangle of intermingled species. At first glance they seem to be squandered by chance, but everything indicates that they are not. And that the threat of that lioness—or leopard, hyena, jackal, or cheetah—is a fundamental piece in that well-thought-out distribution with the intention of not falling into its jaws. 

Actually, even if they seem distracted by their pastures, they are spiing on each other, moved by elective affinities. "Animals often obtain information about the presence of predators by the alarm voices of other members of the same species. Although this idea is well documented and understood, little is known about how animals process alarm calls from different ones," explains Kristine Meise, an ecologist at the University of Liverpool. Being aware of other species can provide crucial survival benefits as it increases the chances of escaping from a predator. "However, not all alarms are equally significant as the species differ in their vulnerability. For example, cheetahs regularly attack gazelles, but not giraffes or buffaloes," says Meise, who checked alongside his colleagues that this is the case with thousands of experiments conducted over a year in an environment of 57 square kilometers of Masai Mara (Kenya).&

zoom in One of the experiments with false predators. Jakob Bro-Jorgensen

researchers spent that year hitting these animals, as in a show hidden-camera television. They placed life-size images of the predators, held on metal supports, and sounded quality recordings with the alarm voices of the various species in the environment, to see how they reacted. After almost 2,500 scares (experiments), it became clear that the jump is greater when they hear the cry of an animal with which they share fears. They published the results is this research last year. But it was necessary to analyze how this fact influences the general behavior of animals,

"It could help conservationists better predict the extinction risk faced by endangered species that rely on information from others," Meise says

"In recent years, ecologists have become increasingly interested in the fact that animals can obtain important information from signals produced by other species, but knowing if this determines who chose to hang out with who was not clear because there are many other possible explanations," says Jakob Bro-Jorgensen, also from the University of Liverpool. "In this study, for the first time we measured all the main factors that can drive social attraction between species across a community and found that intricate information transfer networks govern the social behavior of species with each other," says Bro-Jorgensen. In short, species are joined by those that can be of alarm to them, as long as they are not going to steal their food,

For the study they published this week, Meise and Bro-Jorgensen analyzed these 2,500 scares and other variables and factors that link a dozen herbivorous species that share restaurant in the savannah, to understand what relationships are established between them. The type of stems and leaves they compete on, their alertness, their vulnerability to predators, etc. Through a statistical calculation they discovered patterns that confirmed fieldwork,

zoom in A group composed of several species sharing pastures in Masai Mara. Jakob Bro-Jorgensen

For example, the warty boar (known as Pumba thanks to Disney), which is very vulnerable but unguard, is attracted to the giraffe, sentry first. "While the attraction between antelopes and buffaloes is mutual, the boar's attraction to the more vigilant impala is more one-sided," he says. "These patterns can be explained by the asymmetries between costs and benefits. Antelopes and buffaloes share many predators and both contribute to the group's surveillance, while the impala does not gain much in terms of vigilance by joining the boar, which could also be a competitor for food," he adds,

"Behavioral ecological research generally focuses on interactions between individuals of the same species, but alarm communication networks between different species have the potential to shape the structure of natural communities and influence ecological processes," Meise says in an institution's note. He adds: "It is crucial to discover how animal communities respond to current environmental changes and could help conservationists better predict the risk of extinction faced by endangered species that rely on information from others.