Group :- Craniata (Definite head, Cranium with brain present.)
Sub phylum :- Vertebrata (Vertebral column present.)
Division :- Gnathostomata (Jaws and paired appendages present.)
Super Class :- Tetrapoda (Paired limbs, lungs, cornified skin and bony skeleton.)
Class :- Mammalia(Body covered with hairs. Females have mammary glands.)
Sub Class :- Theria (Viviparous mammals.)
Infra Class :- Eutheria (Placental mammals. Vagina single.)
Order :- Insectivora (Feed on insects.)
Genus :- Erinaceus (Hedgehog)
Geographical distribution
Erinaceus is found in northern hemisphere, West Indies, Africa and India. Cretaceous to Recent.
Habit and habitat
It inhabits holes and bushes during day and it comes out during night to feed. It is omnivorous, feeding on fruits, roots, insects, worms, slugs and other small animals. Hedgehog hibernates during winter. When alarmed or disturbed, it has the habit of rolling its body like a spiny rounded ball.
General Characteristics of Erinaceus (Hedgehog)
Commonly called as hedgehog.
Animal characterized by the presence of sharp backwardly directed spines on dorsal side, while ventral side has soft fur. Body elevated above ground and divided into head, neck, back and abdomen.
Head conical and produced into a small snout bearing nostrils at the tip.
Mouth small bearing 36 sharp pointed teeth.
Eyes small. Pinnae and legs short. No marsupial bone or pouch. Number of ribs 14-15.
Hind and forelimbs short.
A muscle band is found over neck and sides to move spines.
Vagina single, foetus develops within uterus of female, attached by a placenta.
Special Features
These are probably the most primitive of the Eutherians. The brain represents low grade of organization. Cranial cavity is small. The stomach is simple. The allantoic placenta is discoidal and deciduate but there is a provisional yolk sac placenta. Many young are born at a time. When disturbed hairs of dorsal surface become converted into spines and due to strong development of dermal muscles. The animal rolls into a spiny rounded ball.
