Animal undergoing hibernation are at great risk during prescribed burns in winter and the increasing rate of wildfires during hot season due to climate change. However, a new study suggests that hibernating animals do not lose their sense of smell even when in torpor.

The study showed that the tiny and agile nocturnal marsupial known as pygmy-possum could detect smoke during hibernation and can even perform basic actions as response to the changes in temperature in their surroundings.

According to a press release, pygmy-possums can be found in trees along the south-east coast of Australia. Their hibernation could occur anytime of the year and is not linked to a specific season, making them at risk of falling victim to prescribed burns during winters.

These tiny marsupials can be inactive and experience metabolic rest for up to a month, during which they do not need food while their body temperature drop. Typical hibernation spots of pygmy-possums include a nest of bark and leaves in tree hollows, underground and in bird's nests.

For the study, published in the journal The Science of Nature, the researchers conducted an experiment under laboratory conditions on five eastern pygmy-possums who are experiencing torpor.

The researchers noted that hibernating pygmy-possum could still pick up the smell of smoke. However, their subsequent responses depend on their external temperature. If the temperature remains cold at 10 degrees Celsius, no movements were observed from the pygmy-possum.

When their external temperature reaches 15 degrees Celsius, the three male pygmy-possums in the study were aroused enough to be able to move, while the remaining two female could only lift their heads.

The researchers then noted that the drop of temperature in pygmy-possums affected their ability to move. Around 24 degrees Celsius of body temperature, pygmy-possums could perform advanced actions such as climbing up their tails. However, a body temperature below 13 degrees Celsius could cause the tiny possum to have slow basic reactions and movements.

With their findings, researchers recommend the avoidance of prescribe burning during very cold winter days to give hibernating animals that have low body temperature enough time to respond.