The Ecology of Fear


Predator-prey population cycles are commonly illustrated in textbooks using classic stories, such as the 10-year cycle in Canadian lynx (Lynx canadensis) and snowshoe hare (Lepus americanus) populations. The classic story is that when the hare (prey) population density increases, lynx predation increases, which drives an increase in lynx population density. As hare populations decline, lynx populations decline, and plants browsed by hare recover, allowing for the cycle to start again. The observed trends in these coupled populations are usually described as feeding or trophic relationships driven by the predator (e.g. Krebs et al. 1995).

BUT, if you were the hare and you noticed a lot of lynx around, wouldn’t you change your behavior to avoid potential predators? Perhaps you’d be more careful when foraging or maybe you’d even move to a new neighborhood? Sounds reasonable. Work by RMBL scientists and others, shows that prey modify their behavior in sophisticated ways to avoid predators and reduce predation risk. The story becomes a bit more complicated, which also makes it more interesting!

Modified behavioral responses may be beneficial or detrimental to the prey species and are often difficult to separate from a strictly trophic or consumptive relationship. This is where creativity in experimental design comes in. Recognizing and describing these “non-consumptive effects” or antipredator behaviors within predator-prey relationships are what we are calling The Ecology of Fear.

Learn more about experimental design and explore two illustrated case studies of experiments designed to document “fear-modified”; animal behavior in and around the Rocky Mountain Biological Laboratory. Then, we challenge you to design and conduct your own experiment in animal behavior.

Mule Deer Eating Aspen Sunflowers (Summer 2011)

These mule deer (Odocoileus hemionus) near the lab are not so afraid of Danny DeSantiago that they’ll postpone feasting on Aspen sunflower (Helianthella quinquenervis)!

Next Page Introduction to Experimental Design


Peckarsky et al. 2008 Revisiting the classics: considering nonconsumptive effects in textbook examples of predator-prey interactions. Ecology 89(9) pp. 2416-2425