Wildlife Highlights: Wildlife in November – A look into Hibernation
Back for her second column, Lizzie De Lusignan tells us more about UK wildlife in November, with coverage about different types of hibernation. All of this, and an exciting October update…
Illustration by Paige Blake. Please note - all illustrations across Bloom in Doom articles should not be used as scientific IDs.
November is the end of autumn. Here in the UK, that means that the hats, gloves, and scarfs come out,and snuggling up on the sofa with a blanket is the activity of choice for many. Similarly, several species in the UK go into a form of hibernation over the winter.
Hibernation is the act of slowing down the metabolic rate and relying on energy reserves to survive the winter due to a lack of food availability. This slowing down also includes dropping the heart rate and slowing down the breathing to consume as little energy as possible. In the UK we typically think of hedgehogs when we think of hibernating, and indeed they do hibernate, butthey are not the only species in the UK to do so. Below are some other examples of species that hibernate during winter and throughout the rest of the year, and the different ways that they experience hibernation.
Mammals
Alongside hedgehogs, bats and dormice are the only other British mammals to truly hibernate. During hibernation the internal body temperature of a hedgehog is very similar to the temperature outside, and it’s heart rate will drop dramatically from 190 beats per minute to just 20 beats per minute.
Dormice fatten up to double their size in the build up to hibernation, and then create a small nest in the grass to curl up in. They also experience a huge reduction in heart rate, breathing and body temperature to conserve energy. In particularly cold periods outside of winter, dormice can also go into a state of torpor, a deep sleep similar to hibernation which is not seasonal and also allows them to conserve energy.
There are 17 species of bats in the UK and all of them also hibernate, reducing their heart rate dramatically and their breathing to 5 breaths per minute. Bats do occasionally emerge from hibernation to find food and water as well as excrete waste, however this is very energetically costly.
Grass snake - Photo by Erik Karits from Pexels
Reptiles
Reptiles experience a form of hibernation known as brumation. Reptiles are ectotherms and rely on the heat of the sun to regulate their body temperature; therefore, brumation is essential to allow them to live in colder climates during the winter. Similar to hibernation, reptiles will build up fat deposits before brumation and conserve energy by becoming dormant. However, in brumation reptiles do not sleep and they still need to drink water, requiring them to become active for short periods. Typically, reptiles will brumate over winter, however, unlike hibernation, it is not seasonal and brumation can occur at any time of year.
Amphibians
Common toad - Photo by Игорь Куксинский from Pexels
Amphibians such as frogs, toads, and newts also brumate over winter as they are also ectotherms. Some frogs and newts will rest at the bottom of ponds during brumation whilst toads typically brumate under leaves or in burrows. Amphibians in brumation will reduce their metabolism and food intake in response to temperatures that are too low to function normally, their metabolism drops too low to be able to digest food so they stop eating before going into brumation. As brumation is not seasonal this can occur outside of winter.
Insects
Some insects also go through a process of hibernation known as diapause, a process in which an insect’s metabolism and development is slowed down until the climate becomes warmer again. Some butterflies such as the Peacock butterfly will undergo diapause over winter, though diapause is not seasonal and can occur whenever the conditions are unfavourable.
Monarch Butterfly - Photo by Erik Karits from Pexels
Whilst hibernation is often used as a broad term across all animal groups, there are a few biologically different terms for periods of dormancy. Hibernation is a period of reduced metabolism and heart rate in mammals caused by day length and hormonal changes. Torpor is similar to hibernation but can occur in other animal groups, is not seasonal, and is determined by environmental changes and food availability. Brumation occurs in reptiles and amphibians and involves a drop in metabolic rate due to the environmental temperatures and diapause is a period of dormancy and suspended development and growth in response to unfavourable environmental conditions. Despite many species becoming dormant for winter, there is still plenty of wildlife to see, so make sure you take any opportunities to get out and about this November.
October Updates
Back in October, I recommended trying to find some red deer, and if you were lucky, you might get to witness a deer rut. Well, I was very lucky.
Image by Lizzie de Lusignan
We had seen red deer in the Peak District before but only in the distance. We drove around the Peaks hoping we might see some a bit closer, stopping at the side of the road to use binoculars to see they were not deer, but yet more cows. Then suddenly, I didn’t need my binoculars anymore. About 50m from the side of the road was a red deer stag with a harem of about 15 hinds.About 100m behind them was another stag on his own, and on the brow of the hill was a third stag with his own harem. We couldn’t believe our luck! We stopped in the nearest layby and made our way towards the deer.
From the footpath we could see the size of the stags and how impressive their antlers were. They were keeping an eye on each other and occasionally looking over to us too, though we stayed a safe distance in order not to disturb them. The lone stag made it’s way towards the brow of the hill, being watched closely by the third stag who was struggling to round up his hinds. Suddenly the lone stag ran towards the group, causing some of the hinds to panic and run away. The lone male then chased after them, claiming them as his own, though not for long. The stag at the bottom of the hill had been watching closely and saw his chance to claim the hinds himself. He ran up to the hinds, chasing off the lone stag, and led them back to his own harem.
We couldn’t believe what we had witnessed! In less than a minute, the stag on the brow of the hill had lost half of his harem to the male at the bottom, all due to the inexperience of the lone stag in the middle. Whilst this had all happened very quickly, it hadn’t happened quietly. The stags were all bellowing at each other and continued to do so afterwards, throwing their heads back and producing a deep loud roar that echoed across the landscape.
We continued to admire them for a while longer, before heading further up the hill where we found a group of hinds hiding in the long grass. The bellowing continued in the distance, reminding us of how lucky we had been.
Image by Lizzie de Lusignan
Group of hinds by Lizzie de Lusignan
Lizzie De Lusignan
Lizzie is an MSci Zoology graduate from the University of Exeter, where she was then employed whilst living in South Devon. She now lives in Sheffield and works for Twinkl, helping those who teach. She has always loved exploring nature and whilst she now misses the coastal walks and chances of spotting a seal, she is making the most of having the Peak District on her doorstep. She became interested in the communication of conservation during her degree and since graduating she has decided to continue her passion for conservation through writing.