Small Mammals Hit Hard by Rising Heatwaves - Mammal Society

The UK has suffered extreme heatwaves this summer, with 2026 being the first year on record to reach 35 degrees C in May, June, and July. As our summers continue to heat up every year due to climate change, it isn’t just people that are struggling with the high heat, but also our most overlooked wildlife, such as our small mammals.

Shrews, voles, and mice all have very high metabolisms; shrews, for example, have to find food every 2-3 hours to stay alive. This means they also cannot cope well with high temperatures and become easily dehydrated. With the rise of heatwaves, these small mammals will die trying to find water and food, as vegetation drying up leads to a lack of insects, which means they have to spend more time foraging out in the fierce sun.

Across the country, findings of mass deaths of small mammals is becoming more common from mammal recorders. One recorder regularly reports finding 5-10 dead shrews a day throughout the month of July on a tarmac footpath in Stirlingshire. These summer mass casualties are occurring during peak breeding season for these species, when small mammal species boost their populations ahead of a winter decline. This means the impact of heatwaves could have significant ripple effects in the ecosystem, with implications that will be felt months and even years after the initial die-off.