There are 17 species of hedgehog, across 5 genera worldwide*

The 5 genera of hedgehogs in the world are: Erinaceous, Paraechinus, Hemiechinus, Atelerix, and Mesechinus*

The species native to Britain is the Western European Hedgehog

About the Western European Hedgehog

Scientific name – Erinaceus europaeus

Commonly known as – the European Hedgehog

Found in – Britain, Ireland, Southern Scandinavia, Western Europe, and introduced to New Zealand

Lifespan – it is reported that around half do not make it through the first year. If they do, they commonly live 3-5 years, but have been known to live for up to 10 years

Diet – primarily invertebrates including worms, beetles, slugs, caterpillars, earwigs and millipedes. More infrequently, they will eat carrion, frogs, baby rodents, baby birds, birds’ eggs and fallen fruit

Habitat – parks, gardens, farmland, and grassland near the edges of woodlands, mixed woodland, hedgerows and suburban habitats. Wild overgrown areas are particularly important as they provide areas the hedgehogs can hide, sleep, eat, and nest

Defence – if they feel threatened they will erect their spines and curl into a tight spikey ball. The ring of muscle where the spines meet the fur contracts and pulls together like a draw-string bag to enclose all the soft ‘vulnerable’ areas within

Predators – badgers are the main predator of hedgehogs in the UK, and they also compete for the same foods (worms etc). Foxes occasionally attack hedgehogs but cannot get through their defence, and generally the 2 species live side by side. Dogs are responsible for many attacks and injuries on hogs, but struggle with their spikey defence. Hoglets however are more vulnerable and can be prey to a larger range of species including owls, weasels, dogs, and rats

Activity – they are nocturnal, which means they come out at night and sleep during the day, and over the cold months they hibernate. Each night they will walk 1-2 miles to search for food and are solitary but not territorial

Hibernation – triggered by a number of consecutive cold days (around 5C or less), hibernation typically occurs from November to April and allows them to ‘skip’ the cold months which are often lacking in natural food.
It is important they are a good weight (ideally 600g+) before hibernating as during the process they rely on energy from their fat stores.
It is not just a deep sleep – their metabolism slows down, their body temperature drops from 35C to around 10C, they go from having around 190 heartbeats per minute to only around 20 per minute, and they only take about one breath every 2 minutes.
During the hibernation months, it is quite normal for a hedgehog to occasionally ‘wake up’, top-up on food and water, before making another nest to restart hibernation


Anatomy

Size – a fully grown, healthy adult hedgehog will be around 20-25 cm long and weigh around 800-1100g

Characteristics of this species – faintly visible central parting of the spines at the crown of the head, short ears, and a well-developed big toe on the hind foot

Colouration – creamy brown spines, brown-grey fur on face and underside. Can vary from dark brown through to pale, and can sometimes be found lacking in pigment (leucistic) or have no pigment (albino)

Spines – on average an adult has 5,000 – 7,000 sharp spines made of keratin, the same material as your nails or hair. Each spine is around 2-3cm long and lasts about a year before it is shed and replaced by a new one

Tail – a little tail usually between 2cms long

Legs – surprisingly long legs, about 10cm, which means they can run faster than we can walk

Feet – five toes on each foot, and each toe has a powerful claw used for digging. The front feet are sometimes used to de-slime slugs

Senses – poor eyesight but a great sense of smell and hearing


Breeding and Offspring

Young – baby hedgehogs are called hoglets or urchins. A female will typically have 4-5 hoglets per litter, but it can be up to 7

Breeding – mating usually begins in May, with males circling the females making rhythmic ‘huffing’ noises. After mating the male leaves and does not have anything to do with raising young

Gestation – the females are pregnant for around 37 days

First litter – typically born around June, although with milder winters causing shorter hibernations, we are starting to see them as early as the end of April

Second litter – often the European hedgehog has a late litter in September/October producing what are commonly called ‘Autumn Juveniles’. These late-born hoglets have a tough time getting to a healthy weight before the cold weather (hibernation period) occurs

Hoglet stages – born with no spines and weighing 12-20g, they start to go out with mum on short foraging trips when they are around 3 weeks old, and are independent by 8 weeks of age weighing around 250g+. Click on the picture above to see the significant stages of development


For the child friendly version go here – All About Hedgehogs
For more useful information try the following links:
Concerned About A Hedgehog?
Feeding Hedgehogs
Hedgehogs in History


* There have been debates as to whether Hemiechinus and Mesechinus should be seen as closely related to the other 3 genera, and more recently there are discussions into the Mesechinus genera having 4, as opposed to 2, distinct species https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6102679/