What Drives Wolves: Fear or Hunger? Humans, Diet, Climate and Wolf Activity Patterns

摘要

Activity patterns of animals depend on environmental and intrinsic factors. Studies undertaken across the current wolf (Canis lupus) range suggested a number of variables that may be correlated with activity patterns of wolves. These factors vary locally and there has been no attempt so far at defining those that ubiquitously impact wolf behaviour. I compared 11 studies (from Alaska to Israel) to assess the influence of (1) public road density, (2) human population density, (3) human-caused mortality, (4) proportion of domestic animals in wolf diet, (5) proportion of forest, (6) latitude and (7) mean annual temperature on nocturnal wolf activity and movements. Nocturnal activity was mainly correlated to the proportion of domestic animals in the diet and the density of public roads, whereas nocturnal movements were mainly correlated to latitude. The importance of latitude indicates that sun periodicity might represent an important signal (`Zeitgeber') for circadian rhythms in wolves. Environmental constraints such as high temperatures during the day and a higher hunting success in crepuscular periods probably limit the ability of wolves to avoid humans by nocturnal behaviour. I therefore suggest that in regions where wolves hunt wild prey, they experience a trade-off between predation risk by humans and increased hunting success during twilight hours.