Birth in the brushtail possum, Trichosurus vulpecula (Marsupialia : Phalangeridae)

Abstract

Birth has been observed and described in a number of marsupials. However, the ability of the newborn marsupial to move from the uterus to the pouch and locate the teat is still not fully understood. Birth and the path taken by the newborn from the urogenital sinus to the teat within the pouch were filmed in the brushtail possum, Trichosurus vulpecula. Prior to birth, females began to lick the pouch and urogenital sinus vigorously. The young took approximately 2 min to transfer from the urogenital sinus to the pouch and attached to the teat within 10–15 min. To determine the senses used by the newborn possum to reach the pouch, young were removed from the anaesthetised mothers immediately after birth and placed outside the pouch. From the subsequent observations, the newborn possum instinctively crawled upwards. However, when the newborn was in the vicinity of the pouch, odours emanating from the pouch presumably attracted the young. Thus, the senses of gravity and of olfaction were used by the newborn to reach the teat and probably the sense of touch, via the mechanoreceptor Merkel cells around the mouth, allowed the young to attach to the teat.