Tag Archives: risk

The Early Mouse Gets the Cheese

For small animals like the mouse, predators are a constant concern (Image Credit: Jess, CC BY-NC 2.0)

Maximising survival by shifting the daily timing of activity (2019) van der Vinne et al., Ecology Letters, https://doi.org/10.1111/ele.13404

The Crux

All animals need to eat food to survive and maintain their energy balance, but unlike us they can’t just order a pizza and have the food brought to them. They must always forage for food themselves, and every time that they do they expose themselves to predators. Small mammals like mice balance this trade-off by foraging for food at night, when their risk of predation is lowest.

One interesting strategy that mice can employ is to switch their foraging from the nighttime to the day, if they cannot get enough resources during the night or if their nighttime predation risk increases. The authors of today’s paper wanted to develop a model to predict under what conditions these temporal switches would occur, a model which they then tested with mice in the field.

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Scared to Death

Fear itself of a predator is enough to reduce populations of a snowshoe hare, show Macleod at al.

Fear itself of a predator is enough to reduce populations of a snowshoe hare, show Macleod at al. (Image Credit: Dave Doe, CC BY 2.0, Image Cropped)

Fear and lethality in snowshoe hares: the deadly effects of non-consumptive predation risk (2018) MacLeod et al., Oikos 127(3)

The Crux

When we think of a predator-prey relationship, many colorful examples of charismatic animals come to mind: the lion and the wildebeest, the orca and the seal, the owl and the mouse. We think of these organisms locked in an endless battle, with one needing to catch and eat, the other to escape and live. While these are definitely interesting and important aspects of the predator-prey relationship, prey species need to worry about more than just being eaten. These “non-consumptive effects” play into what is called the Ecology of Fear.

This study was an attempt to show that the perceived risk of predation itself was enough to reduce survival in prey species. Unlike previous studies on this question, MacLeod et al. were the first to conclusively show this effect in mammals.

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