When summers become scorching in the heart of the Greater Yellowstone Ecosystem, an immense wilderness area that extends across Wyoming, Montana and Idaho, for elk, bison and other large mammals, keeping cool is not just a matter of comfort, but of pure survival.
A team of researchers from Montana State University decided to investigate how these species react to summer heat peaks. The goal was to understand whether the responses depended more on their physical characteristics – such as size, sex or physiology – or on the type of habitat in which they live.
Landscape determines heat response, not size or sex
The results, published in the journal Ecospherewere surprising: it is the composition of the landscape – and not the biological characteristics – that determines the behavior of animals in the warmer periods.
From the analysis of GPS data collected over 15 years on nine different species (bison, mouflon, ibex, elk, mule deer, wapiti, pronghorn, wolf and puma), it emerged that all specimens slow down, seek shade and reduce their movements during hot days.
But not everyone can protect themselves from the heat with the same ease.
Animals that live in homogeneous, flat environments – such as the prairies of the Shirley Basin in Wyoming – must travel greater distances to find shelter, because their habitats offer very little shade.
“Behavioral plasticity” is the natural response to climate change
The research also highlighted the concept of behavioral plasticity: the ability of animals to quickly adapt their habits to environmental conditions. A real survival strategy that acts much faster than genetic evolution, as researcher Justine Becker explained:
We often think of climate change as an insurmountable threat, but behavior is an immediate resource that allows animals to adapt to change.
This flexibility offers a sort of “biological shock absorber”, especially in environments that allow freedom of movement and access to different micro-habitats: shaded forests, hills, cool valleys and open areas.
A lesson for wildlife management
The value of this study is also practical. Wildlife management agencies must consider the importance of diverse and accessible landscapes.
Jerod Merkle, an ecologist at the University of Wyoming, highlights the importance of “permeable” landscapes, which allow animals to move freely between different habitats during heat waves.
In other words, it is not enough to protect the areas where these animals live today: we must guarantee them access to a mosaic of different environments, because only in this way will they be able to choose where to go when temperatures rise.
This research – the result of a collaboration between state, federal and university agencies – demonstrates that large mammals are not passive victims of climate change. They can react and adapt, but they need complex and diverse landscapes to do so.
And when extreme heat becomes the new normal, finding shelter can mean the difference between life and death.
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