Hedgehog

In Great Britain, mainland Europe, and Africa the hedgehog is as common as a skunk. However the genera is not indigenous to the Americas. Snoop is a member of the phylum Chordata, class Mammalia,
the subclass Eutheria, the order Insectivora, the family Erinaceidae, genus Erinaceinae, and species
albiventris. (2)

 

 

DIET:
The hedgehog is classified as an insectivore, however, they consume both plant and animal products in their diet (1).The hedgehog needs food from the essential food groups fats, proteins, and carbohydrates (2). Insects are the hedgehogs primary source of fat and protein (2). A diet composed entirely of insects is high in protein but is too high in fat and too low in vitamins (1). The primary source of vitamins and minerals for the hedgehog are fruits and vegetables (2).
In the wild, hedgehogs consume a variety of insects, small mice, various fruits, roots, and fungi (1). Hedgehogs forage in open pastures, gardens, and mown playing fields and golf courses (3). The short grasses help the hedgehog capture worms, slugs, and caterpillars (3). In captivity, there are a variety of brands of hedgehog dry foods that may be supplemented with canned cat food, cooked poultry, low-fat cheese, and a small amount of fruits and vegetables (1). The store bought food usually contains a balanced diet of carbohydrates, fats and proteins. The amount of food fed to hedgehogs in captivity is important as hedgehogs are opportunistic foragers and will spend their time foraging for food and taking whatever they find (2). Obesity will cause the hedgehog to become sluggish and is correlated to shortened life spans and proneness to illnesses such as heart disease (1).

 
 

BEHAVIOR:
Hedgehogs are nocturnal. They usually start their nightly activities such as foraging as the sun goes down. In the wild hedgehogs may hibernate or estivate (engage in torpor) depending on the weather (2). In colder climates the hedgehogs hibernate and in the warmer climates they tend to estivate (2). During hibernation the heart rate of the hedgehog will drop almost ninety percent to save energy (2). Hibernation periods may last from a few weeks to six months depending on the severity of the winter (2).The primary defense mechanism of the hedgehog is rolling into a tight ball and protruding it’s quills. The hedgehog is able to form a ball by means of longitudinal orbicularis and panniculus carnosus muscles around the body (1). These muscles pull the skin around the sides and down over the feet and head (1). The hedgehog’s spines can be moved individually by a complex layer of muscles beneath the skin (2). The hedgehog erects it’s spines for protection from potential predators. Also when the hedgehog feels threatened it may hiss or make clicking sounds (2). An interesting behavior exhibited by the hedgehog is called self-annointing. Objects or food with a strong scent may elicit the hedgehog to foam at the mouth (2). The hedgehog will then spread this saliva onto it’s spines (2). The exact reason for this behavior is unknown but there are a few speculations. Some believe that the purpose is part of the hedgehog’s mating ritual and the saliva may act as a scent to attract mates (2). Others believe that this behavior is an addition to the animal’s defense strategies (2). This “self- anointing” may be a part of an effort to blend in with the scent of the surroundings (1).

REPRODUCTION:
Hedgehogs reach sexual maturity almost immediately after being weaned, when they are still little hoglets. However, breeding may be stressful for females if it occurs prior to 6 months of age. The gestation period is about 35 days. Hedgehogs are polyestrus, meaning they may have multiple litters per year, but in nature a female’s peak breeding times will be in summer. During these periods the days are longer and the weather is warmer therefore providing the sow with adequate nutrients supplies. The female hedgehog is an induced ovulate, therefore simply being in the presence of a male, during her estrus phase, will cause her eggs to be dropped. If the female is not in estrus she will forcefully refuse the males advances, which tend to be very persistent. Studies have shown that repeated mating, within 24 hours of each, can cause the sow to have larger litter sizes. However there is a limit at which the repeated mating will cause litter fitness to decrease.(2)When the female finally is ready to mate the defensive spines will lay flat on her back so that the male can mount her. The male will hold unto the spines on her neck during the 2-3 minute copulation. period. Mating usually occurs at night, since hedgehogs are nocturnal. After the 35-day gestation period a litter of 1 to 10 hoglets may be born, although the average size is 4-5 per litter. The most serious concern with larger litters is the higher post-natal death due to lack of sustenance and attention. In captivity, it has been found, that sows are very edgy around the time of their delivery. If a new mother is disturbed she may eat the entire litter of hoglets. Also a sow may confuse one or more of the babies for an afterbirth and consume them to reabsorb nutrition. (2)When the babies are born there is a thin membrane which covers their small white spines. This membrane will fall off within a couple of hours and the hoglets spines will grow quickly and get darker in color. After 3-weeks the babies will begin to stray from their mothers side. Hedgehogs are solitary animals; therefore the male will not be present during the birth and growth period.(2)

ADDITIONAL RESEARCH:
The hedgehog species, Erinaceus europaeus is primarily found in England. Their primary habitat seems to be along the edges of mowed playing fields, which are found closer populated areas, or pasture areas, in which the grass is longer and uncut. The study showed the hedgehog population was most concentrated in playing field areas rather than pasture areas, 3.9+/-0.8 animals per field and 0.7+/- 0.2 animals per field, respectively. These results do not correlate with the food and shelter availability, since
the tall grass of the pastureland would tend to supply a hedgehog with more of both of these resources. However, researchers found that the population densities inversely coordinated with the badger populations. It was concluded that 39% of the difference in population could be due to the mortality rate due to an increase in predators found in the pastureland as well as isolation of hedgehogs from one another in the pasture environment. After reading the methods of this paper I also question whether the population counts were entirely accurate, perhaps the hedgehogs were able to hide more effectively in the pasture area to escape being counted.(3)

Bibliography:1. Wrobel, D. The Hedgehog. New York, New York: Howell Book House: 1997.
2. Kelsey-Wood D. African Pygmy Hedgehogs As Your Pet. New Jersey: TFH Publications: 1995.
3. Micol T., Doncaster C.P., Mackinlay L.A. (1994) Correlates of local variation in the abundance of hedgehogs Erinaceus europaeus. Journal of Animal Ecology, 63, 851-860.