Eco-toxicology Laboratory, Depertment of Zoology, Centre for Advanced Studies, University of Rajasthan, Jaipur - 302004, India, E-mail: sarojbakshi@gmail.com.
Various types of glands in small mammals were observed eg. lagmorphs (chingland, anal gland, inguinal gland, hardenian, infraorbital, lacrymal gland), Columbian ground squirrels (scent gland at mouth and in anal area), Flying phalanger (frontal gland near ears and eye), Deer and Black tailed deer (interdigital gland, metatarsal, tarsal gland) and Cricetus, Neotoma, Peromyscus, Meriones, Tatera, Rhombomys and Rattus all species having midventral glandular organ. The gland in males are significantly larger (P<0.001) than those of females. The species of larger animals with larger size of gland in comparison to smaller size animals. Length, width and area of the gland was found to be highly correlated with body weight (P<0.001). Histopathologically these glands are composed of complexes of enlarged sebaceous alveoli holocrine types. Age and gland size correlated (P<0.01) in P. eremicus males indicating older males had reduced glandular area in relation to younger ones. Gland size correlated with body weight classes male M. hurrianae had larger glands and larger area than females. The scent gland grows throughout the age of the animals. Large number of chemical substances have been identified from mammalian exocrine glands, act as pheromonal in function. First substance identified were musk produced by para anal pouches and preputial glands of musk deer (Moschus moschiferus). A highly volatile constituent of ventral gland secretion of Mangolian gerbil (Meriones unguiculatus) is phenylacetic acid. Scent marking plays an important role in marking the ground or object with urine and gland secretion which is performed by both sexes. Function of scent marking in social hierarchy to maintaining the dominant status of both sexes as dominants saturate the immediate environment with their own odour. Dominant female gerbil significantly (P<0.01) enhances its scent marking activity when in oestrus and males quickly perceive it and dominant female advertises it's ready to mate condition. The role of scent marking by dominant female in group may serve as an innate mechanism of population regulation. Scent marking has a role in defending territory, it does familiarise the animal in its own range of movement. Scent marks provide homeliness to animals and probably also indicate home. The scent marking processes thus assists homeostasis in temperature regulation with special reference to desert condition.
Dominance, Homeliness, Homeostasis, Integumentary glands, Moschus moschiferus, Musk deer, Oestrus, Population regulation, Sebum odour, Social hierarchy
