Being part of the family Erinaceidae, the hedgehog is a spiny mammal that can be found in Europe, Asia, Africa, and also New Zealand, by introduction. There are seventeen known species, which are divided into five genera, and out of all of these there are no native species to Australia and the Americas anymore, as the ones from the Americas have become extinct. Hedgehogs are nocturnal creatures, although some species can be found active during the day, they can also hibernate, although not all do, and they are known to be omnivores.
Description and distribution of hedgehogs
No matter their specie, hedgehogs can be easily recognised by their spines, which are actually hollow hairs, made stiff due to keratin. Unlike the porcupine and its spines, the ones form of hedgehogs do not easily detach from their body. They do fall out then they are young and the first round of spines get replaced with the adult ones, action which is called quilling. They can shed them, however, when diseased or under a lot of stress.
The spines of a hedgehog are not poisonous or barbed, but they can be used as a defence mechanism, when the hedgehog rolls into a tight ball and causes all the spines to point outwards. Depending on the area where they live, some species use this as a last resort, as they have fewer spines, so rolling in a ball would be less effective. They can either flee or even attack the intruder, which can be a bird, a ferret, or even foxes, wolves or mongooses, depending on the specie of hedgehog.
They can reach lengths of 260 mm in adults, with their body being covered by almost 6,000 spines. They can reach a weight of 1,1 kg in adulthood, with males being slightly larger than females. They are normally brownish, having their body covered with brown and white spines. However, ‘blonde’ hedgehogs occasionally occur, due to a rare recessive gene.
As mentioned above, hedgehogs are primarily nocturnal and spend most of the day sleeping under bushes, tall grasses or in dens dug in the ground, depending on their specie. Also depending on the temperature around them and the abundance of food, they can also hibernate, but not all species do.
When it comes to the European hedgehog, which is a wide spread species that can survive across a wide range of habitats, they are also largely nocturnal and mostly can be found hibernating during winter. For those species that do go through hibernation, this process can last the whole month of winter, although some can wake up at least once, to move their nest. During this, their body temperature can decrease to about 2°C, and when they wake up, their body temperature slowly rises to its normal 30–35°C.
Breeding and dietary information
Breeding season usually starts after hedgehogs come out of hibernation. Gestation can last between 31 and 35 days, and they mostly occur during May and July. A litter typically numbers between four and six, and the young are born blind and will little spines. By the time they are 36 hours old, a second coat of spines begins to show, and after approximately 10 days, they can already roll into a ball. Females usually take care of their litter alone, as it is not unusual for a male hedgehog to kill newborn males.
The European hedgehog, as well as the other species known, are omnivorous, eating not only grass, berries and mushrooms, but also slugs, snails, earthworms, beetles, caterpillars and other insects. They can be seen as beneficial in some gardens, as their diet includes all these invasive species, but for some gardeners, hedgehogs can also become pests.
Behaviour and lifespan
Hedgehogs can have a relatively long lifespan. Larger species can live up to 4-7 years in the wild, and smaller species live 2-4 years, with 4-7 years if they are kept in captivity. A lack of predators and a constant and controlled diet can help them reach a longer life span.
When it comes to a European hedgehog, they have a life expectancy of 3 years, however, they can reach up to 10 as well. The main concern, alongside predators, is that they can die of starvation during hibernation. As mentioned above, alongside foxes and wolves, birds are the most common predators of hedgehogs, especially owls and eagles.
Due to better living conditions, lack of predators and a constant food source, as already mentioned above, the hedgehogs kept as pets can have a longer life span. However, in some regions, it is illegal to keep them as pets, and licenses are required for breeding them as well. These actions have been taken as a result of the behaviour of the hedgehogs that have been introduced in non-native areas, such asNew Zealand and islands of Scotland. Hedgehogs were taken to New Zealand from the 1860s to 1890s, and although not all of them survived the voyage, the ones that managed to reach the new territory, have easily adapted and multiplied, causing havoc for the native bird species.
Hedgehogs are also very prone to several types of disease. From cancer, fatty liver disease and cardiovascular disease, to fungal skin infection and ringworms, hedgehogs can be severely affected by these. Cancer is very common in hedgehogs and it can spread very quickly from their bones to their organs. Fatty liver disease can also quickly appear due to a bad diet, which can also lead to problems of obesity and even heart disease. The fungal skin infection they have can also be transmitted to humans, so they need to be handled carefully, in order to avoid any such problems.
Hedgehogs as pests
Those transported in New Zealand have quickly spread throughout the country and their numbers increased exponentially. As they have affected the fauna of the area, especially the population of birds, they have started to be considered as pests. They can also affect other native creatures, such as rare insects, lizards, and also ground nesting birds. Due to this behaviour, they are considered an invasive species, especially in New Zealand and the islands of Scotland. Due to the fact that it was introduced in those areas and has no really natural predators there, the hedgehog was able to develop and increase in numbers alarmingly.
Due to their health problems and the diseases they can also transmit, but also due to the damage they have been known to cause, especially in areas where they lack natural predators, hedgehogs have become known as pests. Hunting them was legal for a while, but now, they are mostly captured and relocated in areas where they can cause less damage, in the mainland.
In other areas, such as Asia, Africa and Europe, hedgehogs are tolerated around the house. They can be helpful in the garden as they feed on invasive species such as snails, slugs or other insects, and in some countries, they are even protected by law.
Depending on the laws of the area, hedgehogs can be even encouraged to develop in one’s garden, or can be trapped and relocated to a specific area. Knowing how and when you can take action against them, in case you need to relocate any hedgehogs from your property, is important. Whether you want to get rid of hedgehogs or just to prevent infestation with them, you need to know what type of actions you can take against them and when is the best time to tackle this problem. Depending on their hibernation and breeding season, traps can or cannot be used, and relocation of the creatures also depends on the laws of your area. Recognising signs of their presence and knowing how to react in this situation is why you need to know more details about prevention and elimination of hedgehogs from your property.