![]() One of the classic studies of predator-prey interactions is the 90-year data set of snowshoe hare and lynx pelts purchased by the Hudson's Bay Company of Canada. Part 3: Exploitation and population cycles ![]() Watch these short video lectures for a very nice overview of predator-prey interactions. What causes prey number to cycle in the absence of predators? Generally the answer is that without predators to suppress their number, prey outstrip available food resources, nesting sites, or some other limited resource and thus begin to suppress their further growth through competition. Interestingly though, there are situations where predators are absent, such as on islands or in other isolated areas where they either never became introduced or where they have died out, and yet prey continue to oscillate in number. As long as predator and prey numbers don't drop to zero, this cycle can repeat indefinitely. This can lead to cyclical patterns of predator and prey abundance, where prey increase in number and then, with abundant food, predator number increases until the predators begin to suppress prey numbers and then decrease as well. ![]() What may require a bit more reflection is that prey, in turn, affect the number of predators because, when prey become scarce, predators may die of starvation or fail to reproduce. It should come as no surprise that predators influence the numbers of their prey. ![]()
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