Representatives of ancient family of tenrecs in human epoch lived mainly at Madagascar and Comoro Islands (from this family only African water shrews lived in Africa). One of their representatives, rather large species, tailless tenrec (Tenrec ecaudatus), had been acclimatized by people at Mauritius Island. After extinction of mankind activity of introduced species had completely changed the nature of island, and evolution at Mauritius Island has gone in other direction. The descendant of tailless tenrec is one of species of Neocene fauna of this island. At tenrecs there is very small brain, and this animal does not differ in complexity of behaviour. For this reason evolution of tenrec descendant has gone to the way of improvement of passive protection that was promoted by fine inclinations getting from the ancestor. The body of ancestral species was covered with wool with bristle-like spikes. This feature had received powerful development at the Neocene descendant, and this way the maurihystrix (literally means “Mauritian porcupine”) – the large tenrec with long spikes, similar to a porcupine, had evolved at this island. The body length of maurihystrix reaches 60 cm at the weight of about 5 kgs. This is plantigrade sluggish animal with short limbs and rather large head. Paws of animal are tenacious, and on fingers strong claws grow, with which help animal gets various food. Head of maurihystrix is lengthened, with peaked forward teeth and nose turned to short mobile proboscis. Wool of maurihystrix is short and bristly, grey-colored; on stomach it is lighter. On top of head of animal wool forms long hair “cop”. The top part of body (back, nape, top part of neck and shoulders) of this species is covered with spikes up to 5 cm long. Along the middle of back the crest of lengthened (up to 15 cm) spikes grows; with its help animal puts to predators dangerous wounds. Spikes of young animals are dark, at adults they gradually brighten. This mammal lives in mountains and other dry places, thus avoiding a competition to Mauritian dwarf pigs, which are more moisture-loving. Maurihystrix is able to climb on trees. Adult individuals do it very clumsily, but young maurihystrixes climb quickly and dexterously. This is solitary animal. Maurihystrix does not avoid relatives, but concerns to them indifferently, not establishing hierarchy. Only at appreciable lack of forage animals show aggression to relatives. Sight at maurihystrix is weak, and eyes are small. For it keen hearing and sense of smell are more important, because the animal often searches for food in high grass where visibility is very bad. This species is omnivorous. The significant part of its diet the vegetative food– roots and fruits of plants – occupies. Also it willingly eats insects and small reptiles, digs grubs and worms from ground. At an opportunity maurihystrix eats carrion. The disturbed animal hisses and rears spikes, having turned sideways aside the enemy. The attacked animal actively shows an opportunity of self-defense, jumping up on four paws and having curved back like a cat. Seasonal prevalence in breeding of maurihystrixes is not expressed. Pairing is not anticipated by the courtsip ritual, and the female raises posterity alone. Twice per one year it gives rise to many cubs – up to 15 ones in one litter. Newborn maurihystrixes are completely defenceless. They are blind, covered with thin wool without spikes. The female arranges for them a den in rich bush, or digs a hole under roots of tree. At week-aged cubs eyes are already opened, and wool becomes thicker. At three-week age they start to move in den actively and try to explore vicinities. Monthly cubs can already not lag behind the female. They abandon the nest and follow mother in wood. At this time at them spikes start to grow. The highest death rate at maurihystrixes takes place during the pass to independent life. The sexual maturity at young animals comes at the age of 18 months. Life expectancy of maurihystrixes reaches 10 years.