Santa Barbara, California
Wisconsin, United States
Other name: STO; Gray Short-tailed Opossum; Brazilian Opossum; Rainforest Opossum; South American Short-tailed Opossum; House Opossum; Colicorto Gris
Scientific name: Monodelphis domestica
Country / Place of origin: South America
History: The Short-tailed Opossum is a small, nocturnal marsupial which is native to rain forests in Brazil, Bolivia, Chile, and Paraguay. The Short-tailed Opossum was introduced to the international pet trade in 1994 and have since become popular pets. Brazil has now prohibited their exportation, so STO's available as pets are all captive bred. The International Union for Conservation of Nature and Natural Resources (ICUN) lists the status of the Short-Tailed Opossum in the wild as being of "Least Concern". The Short-Tailed Opossum is widely used in laboratory research, and was the first marsupial to have its genome sequenced. Genome sequence of the STO has helped our understanding of the evolution of the mammalian immune system.
Appearance: Short-tailed Opossums mature to an average of 5 inches in body length plus 2-3 inches of tail. The body shape resembles a shrew’s, the muzzle resembles a rat’s, and the soft, thick fur resembles a rabbit’s. The body is brownish-gray in color with a lighter shade in the belly area. The ears are large but thin and highly sensitive to sound. The eyes are large and bulging, adapted to foraging at night. The mouth is triangular with sharp teeth. The tail is hairless and prehensile for grasping and climbing. The front legs are shorter than the hind legs.
Average weight: 2 - 5 oz.
Lifespan: 4 - 8 years
Diet: In the wild, Short-tailed Opossums eat fruits, vegetables, insects, and small rodents. In captivity, they can be fed diced fresh fruits and vegetables, cat or ferret food, baby food, canned tuna, cooked egg, mealworms, mineral-powdered crickets, and pinkie mice. Applesauce and fruit cups can be given as treats. Fresh water should always be available.
Housing: Short-tailed Opossums are small enough to be comfortable in a 10-gallon aquarium with a secure wire mess lid. A larger enclosure is better to allow for exercise items like wheels, ropes, and branches. A nesting box should also be provided, as well as hiding places like PVC pipes and flowerpots. The bedding should be soft and absorbent like shredded paper or wood shavings, with nesting material like shredded tissue paper. The Opossums will choose a corner of the cage to use as a toilet, making it possible to train them to use a litter box. The cage must be cleaned and disinfected regularly.
Health issues: Like other small mammals, Short-tailed Opossums are sensitive to drafts and sudden changes in temperature, which make them susceptible to colds and other infections.
Behavior / Temperament / Activity level: Short-tailed Opossums have become popular in the pet trade because they are clean and active. Being nocturnal, they forage and explore at night, consuming night crawling insects and small rodents. They have sharp teeth but hardly bite their owners. They can be easily tamed if hand-raised at a young age. They are best kept alone because they tend to be territorial when mature.
Natural history: Owning Short-tailed Opossums may be illegal in some jurisdictions. It is best to inquire about local laws and licensing before acquiring them as pets.