Hibernation.
Hedgehogs hibernate to bypass the cold months of the year when food becomes scarce. Hibernation, however, is more than just sleeping for a long time. The hedgehog, to some extent, puts itself into a type of suspended animation. Hibernation begins for most hedgehogs in the October or November months. They can be seen wandering about, however right up until Christmas, especially if the hog has not managed to collect enough food to see itself through the winter. They can also be upset by a warmer spell of weather and will wake up and perhaps go for a forage for food.
Whilst the hedgehog is in hibernation, a number of odd things happen to it.
The hedgehog stops being a warm blooded animal since this uses up too much energy. It's body temperature falls to match that of the surronding environment. However, the surrounding temperature must not be below freezing and if it rises too much, the animal's bloodflow will increase and start to use up too much stored fats.
As a result of the above, the hedgehog becomes cold to the touch.
The hedgehog stops moving.
The breathing stops for long periods of time
The heart rate drops to around 20 beats per minute.
Internally, the chemistry of the blood and the major organs all alter to avoid using too much of the stored fats.
So in the hibernation state, the hedgehog's body tries it's best to conserve as much of the stored body fats as it can.
To wake up, the hedgehog needs to metabolise fat which warms the body and begins to get the blood flowing again. The hedgehog may help itself along by shivering. This can all take from 1/2 to 1 hour to complete. Only then does the hedgehog have a normal body temperature and can again venture out into the world.
Obviously, successfull hibernation depends a lot on the surroundings being of an acceptable temperature to allow the body to evenly use up the body fats. To achieve this, the hedgehog will have built a nest somewhere in the weeks leading up to it's hibernation. Hedgehogs do wake up every now and again though, usually due to a warm spell of weather or if, perhaps the nest has become water logged.
Only at the start of spring will the hedgehog start to become fully active again.
Breeding
Breeding takes place soon after the animal has woken from hibernation. The sight of two hedgehogs mating is easy to spot. Mainly because they make such a noise about it! The pair of animals will not be a 'couple'. Any one male hedgehog mates with many females during his lifetime. The pair will circle each other for a long length of time, possibly an hour or so. All this time they will be snorting at each other. It is only when the female is ready, which is not always the case, will mating take place. This is because the female must adopt a special flattened posture to stop the male injuring himself! Once it is all over, the male move on and the female is left to raise the young.
The young are born into a nest which the mother will have built for the purpose. A normal litter would be 4 or 5 young ones. This figure can sometimes be larger, but it will put extra stress on the female as she now has to feed extra mouths. In most case, too many babies will lead to the smallest dying. About 20% of baby hedgehogs will never leave the nest.
When they are born, the babies are bald and the eyes are shut. However, it can be just hours before the first small, white spines start to grow through the skin (see picture to the right). As the young one gets larger, these spines are eventually replaced by spines of the natural colour. The eyes will open after about 10 days.
After a month of growing, the mother will start to lead the young hedgehogs out on feeding trips. It is then only a matter of weeks before the young move on to a life on their own.
The female may have time for a second litter later on in the year. However, this can lead to problems, since the offspring produced on a second litter do not always have enough time to build up their body weight to a sufficient level and meny will perish during the winter hibernation.
The remainder of the time
The hedgehog can live up to 14 of 15 years. Once a female is more than 1 year old, she can start producing litters. However, it is a sad fact that less than half of the hedgehog population probably lives to see it's first birthday. Young hedgehogs can have difficulty finding food and can get too cold since the spines offer poor insulation.
Of those which reach 1 year, the prospect of a long life improves somewhat. Many live to 3 or more and some may even reach 7. It is a very lucky hedgehog which reaches 10 however.
During the night
Hedgehogs spend most of their day sleeping and will only wake up when it gets dark. The sight of a hedgehog during the day can ofter show it has a problem, especially as the winter gets nearer. The hedgehog could still be out collecting food in an attempt to build up sufficient body fats for the winter hibernation.
During the night, a hedgehog moves around a lot. Males can walk up to 3 kilometers in a single night. Females ofter do less however, perhaps just 1 km.
The females will only need to travel to find sufficient food for themselves and any young, whilst the males will need to feed and will also be on the lookout for mates.
The male hedgehog will travel into the domains of several females looking for a mate and may cover a large area in the process. They will ofter visit special food areas which they have come across in past nights, but they do not stick to a rigid area.
As the hedgehog moves about during the night, it will leave a faint scent trail as it's underside brushes against the ground. Apart from that, however, the hedgehog does not mark out any territory with scent or urine.
If one male meets up with another, they will usuallk keep thier distance. Fights are uncommon amongst hedgehogs.
They can swim, although they tire easily and can often drown in a pool or pond which has steep, slippery sides, since it cannot climb out again.
They can also run quite quickly using their long legs. A climbing hedgehog is also not uncommon.
For the major part of the night, the hedgehog will be seeking out food by snuffling amongst the undergrowth. Using their strong sense of smell and keen hearing it seeks out it's prey. As a contrast, however, it's sight is poor. It cannot see the full colour spectrum and manages to survive well even if it has been blinded for some reason.
One strange thing that hedgehogs do is something called 'self anointing'. The hedgehog twists it's body around and using it's tongue, spreads saliva over it's spines. Although it looks a though the animal is having a fit, it is perfectly natural. It is still a mystery, however, as to why it is done.
Hedgehogs can make a loud squeal if frightened, but apart from it's normal snorting and snuffling noises, it makes little other sound.
Wed Feb 06, 2013 4:03 pm
