Svalbard, a group of islands in the Arctic Ocean belonging to Norway, is, in Philip Pullman's trilogy His Dark Materials, the home of a warrior race of articulate armoured bears. In Joel Berger's The Better To Eat You With - an engaging book about how an understanding of predator-prey dynamics can inform conservation biology - we visit the real Svalbard and meet the real bears, who are pretty frightening without any armour.
Berger, a wildlife biologist who comes across as an Arctic version of Indiana Jones, has travelled the world studying variation across prey populations in fear responses to predators. In this book, he relays the trials and tribulations of his journeys to remote, sometimes hostile environments ranging from the Yellowstone ecosystem in Wyoming to the Kolumbe River basin north of Vladivostok in Russia.
The science behind building robust ecosystems is, however, the true subject of the stories Berger recounts. His concern is how to make better conservation management decisions about reintroducing predators, such as wolves, into ecosystems. The conventional wisdom is that reintroduction is not perturbative because the predator was once, usually within a few generations, part of the ecosystem. Thus prey populations in the ecosystem should be "prepared" for the predator. The assumption behind this belief is that the adaptive behaviours that prey employ to evade predators are largely innate and take many generations to lose. Berger calls into question these ideas. He cautions that reintroduction without, for example, a suitable fear response, can lead to rapid and irreversible decline of prey populations.
This cautionary perspective grew out of Berger's many years studying animal behaviour in the wild, where he observed that prey species vary in the amplitude of their fear responses to predators, as well as the extent to which the fear response can be lost and re-acquired. The Alaskan moose observed by Berger in "intact" ecosystems showed strong, adaptive responses to cues indicating the presence of carnivores, whereas Teton moose seemed ignorant of wolves even though the wolves had been missing from the ecosystem for only a few generations.
Berger provocatively suggests that fear is at least partly culturally transmitted through social learning, challenging a widespread view that such fundamental responses are innate. These observations are supported by recent controlled experimental studies showing that many animals, including birds, mice and primates, can learn to be fearful by observing that an event causes pain for a group-mate. These studies suggest that observers use information present in the faces, postures and vocalisations of group-mates to learn that an event has unpleasant consequences.
Consistent with Berger's observations, there are some important species-specific differences in terms of the extent to which the fear response is learnt as well as how it is learnt. For example, primates to a greater extent than ungulates rely on facial expressions to communicate and learn about emotional states. The existence of such differences suggests that reintroduction policies should consider how social and cognitive factors, as well as ecological variables, such as home-range size and population density, influence predator-prey dynamics.
The Better to Eat You With is a compelling read. Berger convinces the reader that legislators of wildlife conservation and management policies need to pay greater attention to animal behaviour in addition to ecology and population dynamics. This rather deep point is made subtly through a riveting narrative about life in the field that involves tramping through snow and sneaking up on moose in a moose suit made by a costume designer from Star Wars.
The Better to Eat You With: Fear in the Animal World
By Joel Berger
Chicago University Press
Published 14 November 2008