The dependence of interspecific differences in the histoenzymatic parameters of skin glands between Norway (Rattus norvegicus) and black (Rattus rattus) rats on their social behavior

Abstract

Relationship between phylogenetically close (especially sympatric) animal species are intensely studied. Two rat species, the Norway rat ( Rattus novegicus Berk, 1969) and black rat ( Rattus rattus L., 1758), are studied in detail because, under the influence of anthropogenic factors, these species have considerably increased their natural range and spread even to large cities [1]. It is known that male Norway rats are more aggressive than black rats, and domination in interspecific social interactions provides more opportunities to Norway rats than to black rats. However, approximately equal body sizes and similar behaviors ensure longterm coexistence of these species with a common social structure. One of the histochemical criteria of social status of mammals is the activity of enzymes of specific skin glands playing an important role in the life of these species [2]. The histochemical specificity of the skin glands of these species has been poorly studied, and only on limited animal populations [3]. In this work, we studied this problem in details. It is known that chemical communication plays an important role in all social interspecific interactions. One of actual problems concerning mechanisms responsible for encoding information on individuals is finding the possible correlation between the metabolic characteristics of skin glands and role of these glands in chemical communication of different animals. The smell of the plantar and anal glands induces exploratory behavior in Norway rats [4]. The plantar glands play an important role in marking behavior. It was hypothesized that plantar eccrine glands play the leading role in the chemical communication of rats [4]. The haired part of the sole also has oil glands, and secretion of these glands may be also involved in smell signaling. Synanthropic species need information on the sex, pregnancy, estrus and diestrum of females; aggressiveness of unknown males; etc. In this work, we studied oil glands of the nape,