The cost-benefit analysis of predators

In encounters between wild animals and humans and other animals predators weigh up the energy cost of attacking.

Wild predators such as the lion, tiger or coyote, decide whether it is worth attacking another animal including the human animal partly on the basis as to whether the cost-benefit analysis comes out as a benefit.

That’s my interpretation of Michelle Jewell’s article on the Southern Fried Science website. She is referring to human to wild animal interactions but I guess it applies to all interactions.

Squirrel demonstrating a cost/benefit analysis = the benefit of free food is higher than the stress my tie-dyed presence is causing.
In Michelle’s words: ‘Squirrel demonstrating a cost/benefit analysis = the benefit of free food is higher than the stress my tie-dyed presence is causing.’ Photo: Michelle.

The argument is that wild animal predators have to weigh up the benefits in attacking over the cost. They have limited energy resources and their decision turns on this limitation because at root their decision affects their survival.

She makes the point that in human to wild animal close interactions if the animal does not attack it is not necessarily because the human has a wonderful way with wild animals. It is because the animal has decided that to attack and respond aggressively (due to being stressed by the human’s presence) is not worth the expenditure of its limited energy resources.

Energy means survival. Without energy the animal dies because it won’t hunt and eat. Therefore there is this constant computation of benefit versus cost. The cheetah is a good example. The world’s fastest land animal can maintain 60+ mph for about 400 yards. The cheetah has to decide to abandon a chase or not to chase prey based on the reward after expending a certain amount of energy. In fact they overheat after 400 yards.

Humans do this calculation too, all the time. Sensible people won’t drive to local shops for food because the cost (gas – petrol etc.) outweighs the benefits (convenience). There are other factors such as the amount of food being bought and therefore carried if they walk to the shops. But that is all part of the cost-benefit calculation.

Michelle thought that she was an animal whisperer and that she could approach wild animals without them biting her. She now realises that they did not bite her because it was not worth the effort.