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

Birth has been observed and described in a number of marsupials. However, t he ability of the newborn marsupial to move from the uterus to the pouch an d locate the teat is still not fully understood. Birth and the path taken b y the newborn from the urogenital sinus to the teat within the pouch were f ilmed in the brushtail possum, Trichosurus vulpecula. Prior to birth, femal es 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 anaesthetise d mothers immediately after birth and placed outside the pouch. From the su bsequent observations, the newborn possum instinctively crawled upwards. Ho wever, 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 th e sense of touch, via the mechanoreceptor Merkel cells around the mouth, al lowed the young to attach to the teat.