The humble cow, often seen as a symbol of pastoral tranquility, may be the unsung hero of hillside architecture. A recent study led by the University of Colorado Boulder challenges the conventional wisdom that terracettes, those staircase-like ridges found on hillsides worldwide, are solely the result of gravity's relentless pull. Instead, it reveals a fascinating interplay between nature and the foraging behaviors of grazing animals.
The research, published in the Journal of the Royal Society Interface, highlights how cattle and sheep, through their seemingly mundane activities, can inadvertently sculpt the landscape. Saad Bhamla, an associate professor in the Department of Chemical and Biological Engineering and the BioFrontiers Institute, remarks, 'It's a reminder that even the most ordinary creatures can have a profound impact on our environment.'
The story of terracettes began with a curious observation by Ben Seleb, a former graduate student who noticed the intricate patterns during a trip in the Swiss countryside. These patterns, colloquially known as 'cow trails' or 'sheep tracks,' had long been attributed to gravity. However, Seleb, now a postdoctoral engineer at the Rockefeller University in New York, suspected that animals deserved more credit for their role in shaping these landscapes.
To test this hypothesis, the team developed a computer model simulating the foraging behavior of grazing animals. The model revealed that animals naturally prefer paths with minimal elevation change, as uphill travel requires additional energy, and downhill walking is uncomfortable. This preference leads to the creation of horizontal bands across hillsides, with animals carving out new paths as they eat the grass along existing ones.
Seleb uses a lawn mower analogy to illustrate this point: 'I'd rather take these horizontal paths. But once I've already cut one path, I don't need to cut it again. So I'll take the smallest step up or down the slope to mow the next strip.' Over time, these decisions made by many cows result in the formation of terracettes, challenging the notion that animals cannot create such regular patterns alone.
While gravity may still play a role in terracettes formation, the study suggests that grazing animals alone can lead to these natural staircases. Bhamla emphasizes the importance of maintaining an open mind, stating, 'Sometimes the mundane turns out to be fascinating. We just have to keep an open mind and spend a little time looking.'
This research not only sheds light on the hidden agency of animals in landscape formation but also invites us to reconsider the complexity of natural processes. As Seleb notes, 'It makes sense to me that cows can do it too. So I took it upon myself to defend the cows' agency.' This study serves as a reminder that even the most ordinary phenomena can reveal extraordinary insights when we approach them with curiosity and an open mind.
