gh WILD AND HOMEBODY SPECIES

Two field-vole species, which are outwardly indistinguishable, behave differently towards human beings. Results of experiments carried out by the specialists of the Institute of Ecology and Evolution Problems, Russian Academy of Sciences, and the Lomonosov Moscow State University connect these differences with the exploratory behavior of field-voles. Timorous and incurious common voles (Microtus arvalis) prefers country life, and inquisitive European ground voles (Arvicola terrestris) readily move into human lodgings.

To investigate field-voles' behavior, the researchers constructed a case (its side being equal to 4 meters) imitating a living room. There was a can, a bottle, small boxes, shoes, a shelter, feeding-racks and a drinking bowl, a tray with a flower, chairs, suitcase, a camp-bed with a pillow and a bedside-table in it. The field-voles involed in the experiment were born in captivity. Their belonging to a certain species was confirmed with the help of haemoglobin analysis. The small animals were carried into the room in the shelter, which previously used to stand in its dwelling cage, and were observed for two hours after the animal had left the shelter. The common voles got frightened of unfamilar environment. They rushed to reach the wall of the cage and would sit there, hiding themselves, or would run along the perimeter of the room or along the wall. Their bustle seemed to have only one target - to find the exit immediately. The animals even threw themselves to the walls. Having made sure that their efforts are in vain, the common voles tried to find the cover without running out, if possible, to the middle of the room. Most frequently, they would hide themselves in the suitcase, and that ended their investigation of the room. Besides the shelters, rodents were interested in the feeding-rack, if they passed by. The objects, which were of no practical importance, as well as the high object, did not attract them. Only one animal courageously climbed up the chair and concealed itself in the flower tray where it stayed through the end of the experiment. But none of them climbed under the pillow in its fright, although such a possibility was available.

The European ground voles behaved in a different way. They immediately started to actively and systematically inspect the territory. They were interested in everything, they wanted to climb around, to look over, to sniff around and to touch all over. Even having found the feeding-racks and having chosen an appropriate shelter, the animals continues to examine the room, sometimes only the experimentalist's interference broke off this enthralling occupation. The European ground voles were not afraid of open spaces and ran bravely across the middle of the room, but their favorite spot was the suitcase again, but they had no special liking of the pillow on the camp bed, although some animals used to hide there.

When examining a new space the common voles mainly rely upon the sense of smell. Running along the room they lowered the head and sniffed around the floor and unknown objects. The Europen ground voles preferred to look around without stopping and often rose to their hind feet to view environment and objects. Having passed around each object and having descried it thoroughly, the animals touched it over with forepaws and vibrissa.

The common voles dislike new things and even are afraid of them. The investigation activity of the European ground voles is higher than that of their twin-species and is more intelligent. Such strategy of investigating unfamiliar space allowed them to accomodate themselves to life nearby human beings and to settle in town and in the country. They willingly feel at home in unknown closed premises, including human houses where they wait through winter cold weather. Therefore, the researchers consider the European ground vole to be a synanthropic species, and the common vole - rather wild species.

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