WINTER HIBERNATION
Living in Wenvoe we see a pleasing range of wildlife in our garden and in the nearby woods. In fact, we once walked the Great Glen Way in Scotland from Fort William to Inverness and later wrote to the Scotsman newspaper to say that we saw more wildlife in our garden in Wales than we did hiking across Scotland from one side to the other!
Most common are grey squirrels and hedgehogs, though we did have refugee pheasants and like most gardens we saw the odd rat or mouse. In winter we saw little of the squirrels and hedgehogs as they hibernate for winter, retreating to their warm and cosy nests and staying there until the spring.
There is more to hibernation than you may think. Hibernation is really a survival strategy used by many animals to conserve energy during harsh conditions such as winter, by slowing their metabolism, lowering body temperature, and reducing activity.
Hibernation is a state in which an animal instinctively lowers its metabolic rate that allows animals to survive periods when food is scarce and temperatures are low. Unlike ordinary sleep, hibernation involves profound physiological changes: body temperature drops, heart rate slows dramatically, and breathing becomes minimal. In some species, metabolic activity can fall to just 5% of normal levels. This adaptation enables animals to endure weeks or even months without eating. In the Arctic, for example, the Ground Squirrel can hibernate for 7 to 9 months. While in the European Alps the loveable Marmot can disappear underground for 7 or 8 months.
Our Wenvoe hedgehogs can hibernate for a few weeks or several months. During this time their heart rate drops by as much as 90%, but if it becomes too cold, they briefly wake up. This causes their hearts to beat faster and so warm them up before they go back to sleep.
Before entering the state of hibernation, animals must store energy. Larger mammals, such as bears, eat excessively in autumn, building fat reserves that sustain them through winter. Smaller creatures, like squirrels and hedgehogs, often cache food in burrows to consume during brief wakeful periods. Some species also grow thicker fur or develop special behaviours to insulate themselves against the cold.
During hibernation, and to survive without food, in addition to the reduced heart rate, the breathing will slow down greatly and body temperature drops. At the same time the animals undergo chemical changes which manage their waste and maintain muscles. It is a controlled energy saving state, it is distinct from sleep.
We can help these garden animals like hedgehogs and squirrels by feeding them in the winter months partly to ensure they have the fat reserves for hibernation, but also because in winter their normal foods are scarce. So do put out good quality cat food or dog biscuits and plenty of water, but do not feed them milk which is not good for them.
In summary, hibernation is a complex, finely tuned adaptation that enables animals to endure periods of cold and scarce food. By slowing their bodies almost to a standstill, creatures from bears to hedgehogs demonstrate nature’s extraordinary ability to survive in challenging environments
