Hedgehog

A hedgehog is a spiny mammal of the subfamily Erinaceinae, in the eulipotyphlan family Erinaceidae. There are 17 species of hedgehog in five genera found throughout parts of Europe, Asia, and Africa, and in New Zealand by introduction. They are not native to Australia or the Americas, though an extinct genus called Amphechinus once lived in North America.

Hedgehogs are closely related to shrews, with gymnures possibly acting as an intermediate link. These animals have changed very little over the last 15 million years. Like many night-active animals, hedgehogs are mostly active at night and have developed sharp spines for protection, similar to porcupines and echidnas, though they are very different from these animals.

In Europe, hedgehogs are often brought to wildlife clinics for care. They are delicate animals and can become very stressed around humans. To keep them safe during treatment, clinics suggest placing them in a dark, quiet, and well-ventilated box and limiting handling to give them a calm environment.

Etymology

The word "hedgehog" started being used around the year 1450. It comes from an old English word, heyghoge, which means "hedge" and "hog". People called them this because hedgehogs often live in hedgerows and have a snout that looks like a pig. Other names for hedgehogs are "urchin" and "hedgepig".

Main article: Middle English

Description

Hedgehogs are small mammals known for their spiny coats. These spines are not poisonous or barbed like a porcupine's quills and do not easily fall off. When threatened, hedgehogs can roll into a tight ball, using their spines to protect themselves. They are mostly active at night and like to sleep in dens they dig underground.

Hedgehogs can make many different sounds, such as grunts and squeals. They sometimes perform a behavior called anointing, where they lick a new scent and then spread it on their spines, possibly to hide from predators. Hedgehogs also have some natural protection against certain snake venoms, which helps keep them safe.

Diet

Hedgehogs are omnivores, which means they eat both plants and animals. They enjoy a variety of foods including insects, snails, frogs, toads, snakes, bird eggs, carrion, mushrooms, grass roots, berries, and melons. Afghan hedgehogs particularly like to eat berries in early spring after their hibernation. Sometimes, hedgehogs also eat cat food that is left outside for pets.

Hibernation

When a hedgehog hibernates, its body temperature drops from its usual 30–35 °C (86–95 °F) to just 2–5 °C (36–41 °F). During this time, the hedgehog rests and conserves energy until it is time to wake up again.

Reproduction and lifespan

Hedgehogs have a gestation period of 35 to 58 days, depending on the species. Larger species usually have litters of three to four newborns, while smaller species have five to six. Newborn hedgehogs, called hoglets, are born blind and their quills are covered by a thin membrane that dries and falls off after a few hours.

Hedgehogs can live quite long for their size. In captivity, they may live eight to ten years. In the wild, larger species live four to seven years, and smaller species live two to four years. This is longer than mice, which typically live about two years.

Predators

Hedgehogs have many natural predators. Forest hedgehogs are often hunted by birds, especially owls, and ferrets. Smaller hedgehogs, like the long-eared hedgehog, are preyed upon by foxes, wolves, and mongooses. In Britain, especially in areas with lots of farming, the European badger is also a predator of hedgehogs. Badgers also compete with hedgehogs for food, which can make it harder for hedgehogs to find enough to eat. Some hedgehog rescue groups choose not to release hedgehogs into areas where badgers live to protect them.

Domestication

Main article: Domesticated hedgehog

Many pet hedgehogs are hybrids of the white-bellied hedgehog or four-toed hedgehog and the smaller North African hedgehog. Other species kept as pets include the long-eared hedgehog and the Indian long-eared hedgehog.

As of 2019, it is illegal to own a hedgehog as a pet in some places, such as Hawaii, Georgia, Pennsylvania, California, New York City, Washington, D.C., and certain Canadian areas. Special licenses may be needed to breed them. In most European countries, there are no such rules, except in Scandinavia. In Italy, keeping wild hedgehogs as pets is not allowed.

As invasive species

Hedgehogs introduced to places like New Zealand and parts of Scotland have become problematic because they have no natural predators. In New Zealand, they have harmed many native animals, including insects, snails, lizards, and birds that nest on the ground.

Efforts to control hedgehog populations can be difficult. For example, on some Scottish islands, plans to reduce their numbers faced opposition from animal welfare groups. Over time, methods changed to focus on trapping and moving hedgehogs instead of removing them.

Diseases

Hedgehogs can get many of the same diseases that other mammals do, such as cancer, fatty liver disease, and cardiovascular disease. One common cancer in hedgehogs is squamous cell carcinoma, which can spread quickly. Fatty liver and heart disease often happen when hedgehogs eat too much fatty or sugary food, even though their bodies are made to eat insects with less fat.

Some hedgehogs develop wobbly hedgehog syndrome, and they can also get pneumonia, which makes it hard for them to breathe. They can sometimes pass a skin infection called ringworm to people or other hedgehogs.

Balloon syndrome

Main article: Balloon syndrome

Hedgehogs can rarely get a condition called balloon syndrome, where gas gets trapped under their skin and makes them look inflated. This happens because their skin can stretch and curl up. In one case reported by the BBC, a hedgehog was almost twice its normal size. Vets can help by removing the air and giving antibiotics.

Human influence

Hedgehogs often live near humans, which can sometimes lead to them getting into danger, such as being hit while trying to cross roads. In Ireland, hedgehogs are frequently among the small animals that are hit by cars.

Studies have shown that hedgehogs are actually more common in cities and towns than in the countryside. This means that many hedgehogs make their homes in urban areas.

Culinary and medicinal use

Hedgehogs have been used as food in many cultures, including Ancient Egypt and during the Late Middle Ages. In some places, like the Middle East and among Bedouins, hedgehog meat was believed to help with health problems such as rheumatism and arthritis.

In Morocco, parts of the hedgehog were used in different ways to treat various illnesses. Some people believed that eating hedgehog meat or using its blood and fat could cure different ailments. Even today, some groups like the Romani people still cook and eat hedgehogs. In 1981, a British pub created special crisps called "Hedgehog Flavoured Crisps," but they didn’t actually contain hedgehog meat, so the name had to be changed.

Genera and species

See also: List of erinaceids

Hedgehogs belong to the subfamily Erinaceinae. There are five groups, called genera, of hedgehogs. These include the Four-toed hedgehog, European hedgehog, and Desert hedgehog, among others. Hedgehog species live in parts of Europe, Asia, and Africa, and one type has been introduced to New Zealand.

Society and culture

Hedgehogs are often seen as clever and wise in stories from Asia and Europe, and in Africa, they are linked to magic. In Britain, hedgehogs are frequently voted as one of the most loved animals.