"Predation risk" and "fear" are concepts well established in animal behavior literature. We expand these concepts to develop the model of the "landscape of fear". The landscape of fear represents relative levels of predation risk as peaks and valleys that reflect the level of fear of predation a prey experiences in different parts of its area of use. We provide observations in support of this model regarding changes in predation risk with respect to habitat types, and terrain characteristics. We postulate that animals have the ability to learn and can respond to differing levels of predation risk. We propose that the landscape of fear can be quantified with the use of well documented existing methods such as givingup densities, vigilance observations, and foraging surveys of plants. We conclude that the landscape of fear is a useful visual model and has the potential to become a unifying ecological concept.

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The elk or wapiti (Cervus elaphus) and bison (Bison bison) of Yellowstone National Park have lived in an environment free of wolves (Canis lupus) for the last 50 years. In the winter of 1994-1995, wolves were reintroduced into parts of Yellowstone National Park. Foraging theory predicts that elk and bison would respond to this threat by increasing their vigilance levels. We tested this prediction by comparing vigilance levels of elk and bison in areas with wolves with those of elk still in "wolf-free" zones of the Park. Male elk and bison showed no response to the reintroduction of wolves, maintaining the lowest levels of vigilance throughout the study (≈12 and 7% of the time was spent vigilant, respectively). Female elk and bison showed significantly higher vigilance levels in areas with wolves than in areas without wolves. The highest vigilance level (47.5 ± 4.1%; mean ± SE) was seen by the second year for female elk with calves in the areas with wolves and was maintained during the subsequent 3 years of the study. As wolves expanded into non-wolf areas, female elk with and without calves in these areas gradually increased their vigilance levels from initially 20.1 ± 3.5 and 11.5 ± 0.9% to 43.0 ± 5.9 and 30.5 ± 2.8% by the fifth year of the study, respectively. We discuss the possible reasons for the differences seen among the social groups. We suggest that these behavioural responses to the presence of wolves may have more far-reaching consequences for elk and bison ecology than the actual killing of individuals by wolves. 1409 Resumé : Durant ces 50 dernières années, le Wapiti (Cervus elaphus) et le Bison (Bison bison) du parc national de Yellowstone ont vécu dans un environnement d'où le Loup (Canis lupus) était absent. Les loups furent réintroduits dans certaines parties du parc pendant l'hiver 1994-1995. La théorie admise prédit que le Wapiti et le bison devraient répondre à cette menace en augmentant leurs niveaux de vigilance. Nous avons testé cette prédiction en comparant les niveaux de vigilance des Wapitis et des bisons vivant en zones avec loups avec ceux des Wapitis vivant en zones « sans loups ». Les Wapitis et bisons mâles n'ont montré aucune réponse à la réintroduction du loup, maintenant leur vigilance au niveau le plus bas rencontré pendant l'étude (≈12 et 7 % du temps de vigilance). Les Wapitis et bisons femelles ont montré une vigilance significativement plus importante dans les zones avec loups que dans les zones sans loups. Nous avons rencontré le niveau de vigilance le plus haut (47,5 ± 4,1 %; moyenne ± erreur type) dès la 2 e année dans la zone avec loups chez les Wapitis femelles avec des petits. Celles-ci ont maintenu ce niveau durant les 3 années suivantes de l'étude. À mesure que les loup sont gagné les zones qu'ils n'occupaient pas au début de l'étude, les niveaux de vigilance des Wapitis femelles vivant dans ces zones, avec ou sans petit, peu à peu, de leurs valeurs initiales respectives de 20,1 ± 3,5 et 11,5 ± 0,9 % à des valeurs de 43,0 ± 5,9 et 30,5 ± 2,8 % atteintes au cours de ...

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