BBC Nature - Tiny shrews ?warm up? before cold dives
According to scientists the shrews were achieving the heat boost by shivering or using "brown fat" - tissue found in many small mammals that can generate heat without them exercising.
"What we're thinking is that they are increasing their body temperature to increase their sensory system," said Dr Campbell.
The water shrews employ sophisticated senses of hearing and touch to make them efficient hunters.
They are even known to "smell" underwater, bubbling air from their nose close to potential prey before sucking it back in.
The researchers suggested any drop in temperature would have a negative impact on these systems.
"They're going for shorter dives but they're much more efficient."
According to scientists the shrews were achieving the heat boost by shivering or using "brown fat" - tissue found in many small mammals that can generate heat without them exercising.
"What we're thinking is that they are increasing their body temperature to increase their sensory system," said Dr Campbell.
The water shrews employ sophisticated senses of hearing and touch to make them efficient hunters.
They are even known to "smell" underwater, bubbling air from their nose close to potential prey before sucking it back in.
The researchers suggested any drop in temperature would have a negative impact on these systems.
"They're going for shorter dives but they're much more efficient."