In gray opossums

CHARACTERISTICS OF SCENT MARKING BEHAVIOR IN MARSUPIALS AND MONOTREMES Scent Marking in Gray Opossums... 

Sex and age relationships to scent-marking in gray opossums. Male gray opossums marked significantly more frequently than females (P < 0.005). Males marked with head, flank and chest, while diestrous females marked only with head and flank. Gray opossums tended to place... 

Functional significance of scent-marking in gray opossums. 

Social aspects of scent-marking in gray opossums. As previously noted, little is known about the natural social behavior of gray opossums. In a laboratory study of sexual behavior in this species, males placed into cages recently occupied by females sniffed and then scent-marked areas of the cage using the chest, flank, and head (Trupin and Fadem, 1982). 

THE EFFECTS OF OLFACTORY COMMUNICATION ON FEMALE REPRODUCTIVE PHYSIOLOGY IN GRAY OPOSSUMS... 

Estrus, ovulation and mating were expected to occur in a random pattern over the 32 days ("ideal" estrous cycle length) following the familiarization period. Since the gestation period is approximately 15 days in gray opossums, and there was a two day familiarization period, births were expected to occur uniformly over the 17-49 days following pairing, A chi-square test for uniform occurrence of births between days 17 and 49 was therefore conducted. 

Jackson L.M. and Harder J.D. (1996). Vomeronasal organ removal blocks pheromonal induction of estrus in Gray Short-tailed Opossums (Monodelphis domestica). Biol Reprod 54, 506-512. 

Poran, N. S Vandoros, A., and Halpem, M., 1993, Nuzzling in gray short-tailed opossum I Delivery of odors to the vomeronasal organ, Physiol. Behav. 53 959-967. 

CHEMICAL COMMUNICATION IN GRAY SHORT-TAILED OPOSSUMS (MONODELPHIS DOMESTICA) WITH COMPARISONS TO OTHER MARSUPIALS AND WITH REFERENCE TO MONOTREMES... 

Various aspects of chemical communication have recently been studied and reported for one South American didelphid, the gray shorttailed opossum (Monodelphis domestica), hereafter referred to as the gray opossum. Scent-marking behavior was described and conspecific responses to olfactory cues quantified in a recent study (Fadem and Cole, 1985). 

Fig. 2. The suprasternal scent gland in a male gray opossum (a). A section through this gland (b). (Fadem and Schwartz, 1985.)...

Chest-marking in the koala occurred primarily upon introduction to an unfamiliar tree and declined thereafter. Females rarely chest-marked (only one chest mark was seen in over 20 15-min trials), and highest levels of chest-marking behavior were seen in males 5-10 years old males 1-2 years old marked less frequently (Fig. 5). This is probably related to the fact that puberty occurs at between 1 and 3 years of age and the sternal gland first appears at about 1 year of age in this species (Thompson, personal communication). Thus, age, sex, and time-related aspects of scent-marking in the koala were remarkably similar to those seen in the gray opossum (c.f.. Fig. 1). 

Estrous synchrony in the gray opossum. Each symbol represents the first day of a period of estrus (Fadem and Ra3rve, 1985). 

The results of this experiment indicated that a factor associated with males altered the expected occurrence of estrus in female gray opossums. To obtain information on the nature of this factor, the temporal pattern of the appearance of vaginal estrus following sensory exposure to males without actual mating stimulation was then examined. 

The temporal pattern of the appearance of vaginal estrua in female gray opossums prior to and following the introduction of males to the experimental group. Each bar represents one period of estrus (Fadem, 1985). 

Fadem B.H. (1989). The effects of pheromonal stimuli on estrus and peripheral plasma estradiol in female gray short-tailed opossums. Biol Reprod 41, 213-217. 

Poran N.S., Vandoros A. and Halpem M. (1993). Nuzzling in the Gray Short-tailed Opossum, I Delivery of odors to vomeronasal organ. Physiol Behav 53, 959-967. 

Schwanzel-Fukuda M., Fadem B., Garcia M. and Pfaff D. (1988). Immunocytochemical localization of LHRH in the brain and Nervus terminalis of the adult and early neonatal Gray Short-Tailed opossum (Monodelphis domestica). J Comp Neurol 276, 44-60. 

Puberty acceleration has also been found in a marsupial. The odor left behind in a cage by a male can accelerate the time of first estrus in a female gray, shorttailed opossum, Monodelphis domestica, from 161 to 126 days of age (Stonerook and Harder, 1989). 

Stonerook, M. J. and Harder, J. D. (1989). Male pheromones advance the age of first estrus in the gray, short-tailed opossum, Monodelphis domestica. Biology ofRepmduction 40(Suppl.l), 157. 

Jia C, Halpem M. 2004. Calbindin D28k, parvalbumin, and calretinin immunoreactivity in the main and accessory olfactory bulbs ofthe gray short-tailed opossum, Monodel-phis domesliea. J Morphol 259 271-280. 

Poran, N. S., Tripoli, R., and Halpern, M, 1993a, Nuzzling in the gray short-tailed opossum 11 familiarity and individual recognition, Physiol. Behav, 53 969-973. 

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