| abstract
| - In Neocene of South America armadilloes had taken a significant place in fauna. They successfully compete to rodents, and one species became . Among Neocene armadilloes one species which conducts practically completely underground way of life had evolved. This small animal is named digging armadillo. Digging armadillo is deeply adapted to a underground habit of life. The body of animal is about 25 cm long. It has almost cylindrical shape and is covered with strong armour. In the middle of trunk the armour of animal forms five belts connected by elastic skin. These belts allow digging armadillo to turn off in ball and to turn round in its own tunnels. Tail of this animal is short and wide in the basis and has triangular outlines. Edges of corneous belts of tail form thick strong prickles. Resting them in floor and walls of hole, animal provides a reliable support at digging to itself. At this animal there are short limbs. Hinder legs of digging armadillo are rather weak and three-toed. Forepaws are wide and muscled, armed with three huge claws (the largest claw on middle finger reaches length of 4 cm, claws on third finger and forefinger are shorter). During the digging animal supports on prickles on edges of tail, and rakes ground out by claws of forepaws. Friable ground is raked back by hind legs. When the rather large amount of it is gathered, digging armadillo turns tail under stomach, and moves back, pushing ground to the exit of hole. On the ground surface this animal is very cautious, and the predator practically can not creep to it imperceptibly. Digging armadillo feels keenly vibrations of ground, and feels approaching of large animals how they will see it. Digging armadillo is practically blind. Its eyes are shifted in the bottom part of head and are very small. In them there is no crystalline lens, and the animal can distinguish light from darkness only. The head of digging armadillo is covered with thick corneous plate in which basis thick skull bones lay. Ears of animal are very short, protected from ground by rigid bristles. The forepart of muzzle is protected by “visor” of corneous plate, and nostrils are supplied with muscles permitting them to close. At digging of friable and dry ground animal can hold the breath till 1 – 2 minutes. Due to such features of anatomy the animal is able not only to dig tunnels but also to swim. Digging armadillo can successfully swim across small rivers, being guided on smell of air above water. During the swimming it rows by forepaws, and turns rear legs in sides, and they serve for balance. Digging armadillo eats various ground invertebrates, but the vegetative food – roots and tubers – makes about 20 % of its diet. This animal prefers to settle in areas with small amount of wood vegetation. Digging armadillo often builds the common systems of holes with some local rodents, but such neighbourhood not always passes without conflicts – digging armadilloes willingly eat newborn rodents. In southern regions of area this animal runs into not deep winter dormation, does not dig new tunnels and does not leave on ground surface. In the beginning of spring at digging armadilloes the courtship season begins. Male is larger, than female, and behaves more aggressively. It searches in tunnels of females ready to breeding, pairs with them and does not accept participation in care of posterity any more. In 7 weeks after pairing in deep hole the female gives rise to posterity – 4 cubs which always are enzygotic twins. While they are small, the female often comes back to feed them, but since the third week of life cubs can follow freely the female in tunnels and gradually pass to diet of adult animals. They become sexually mature at the age of half-year.
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