The author of this book, Daniil Nikolaevich Kashkarov—a professor in the Department of Vertebrate Zoology at Leningrad State University—prepared the manuscript for publication on the eve of the Great Patriotic War. Daniil Nikolaevich initially worked in the field of comparative anatomy (as a student of M. A. Menzbir), then in animal psychology, and finally—via the study of faunas—transitioned to ecology. He was particularly captivated by this last discipline, and for a number of years, he was the most prominent and energetic figure in the field of animal ecology in our country. During the blockade of Leningrad by German invaders, Daniil Nikolaevich was evacuated from the city by plane; he died of heart disease on November 26, 1941, at...