How Mongolian voles protect themselves from predators.
If someone always trims the lawn to matchstick length, this is often ridiculed and here and there even ostracized as an act of pure philistinism. Little attention has been given to the idea that this might be a survival mechanism that our species trained when we fled from the saber-toothed tiger like the vole from the farm cat. So it could be read these days that the length of the lawn and the length of life are directly related to each other – at least in the world of the Mongolian vole, whose European relatives sometimes have very close connections with people or their green spaces.
A team of researchers from the UK, China and the US has found that Mongolian brandt voles shorten the grass in front of their burrow to get a better view of predators. In their article in the journal “Current Biology”, the scientists explain that the mice align their behavior with the appearance of a species of bird known as a shrike.
Because the shrike is to the mouse in the Mongolian grasslands in a way what gravel gardeners are to insects in this country, whenever shrike were around, the voles “drastically reduced the amount of grass growing in clumps,” says Dirk Sanders from the University of Exeter. With the effect that the stranglers came less often – apparently they considered trimmed areas to be bad hunting grounds. On the other hand, if there are no shrikes, the mice stop cutting the grass. Which is no wonder, since trimming the lawn – experts call such activities “ecosystem engineering” – costs a lot of energy. And animals and plants only use this energy if “it brings a significant survival advantage”, as Sanders says.
Zhiwei Zhong, who researches at Northeast Normal University in China and was also involved in the study, has bad news for the voles. According to him, the results could be useful for controlling rodent populations on rangelands: “Maintaining or planting large, clump-growing grasses could help attract shrikes, thereby reducing vole populations.”
Until grass has grown over the whole thing, not only voles have to be very strong, but also the people who don’t want voles in the garden. And love the grass for short.
