Delicate Slender Opossum
| Delicate Slender Opossum | ||||||||||||||||
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| Missing image Delicate_slender_opossum.jpg Delicate slender opossum | ||||||||||||||||
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| Binomial name | ||||||||||||||||
| Marmosops parvidens (Tate, 1931) |
| Missing image Stop_hand.png | The factual accuracy of this article is disputed. |
| Please see the relevant discussion on the talk page. |
The Delicate Slender Opossum, Marmosops parvidens, is a small pouchless marsupial of the family Didelphidae. Though not specialized for subterranean life, they mostly live underground in heavily wooded areas in river valleys, rain forests, and swamps in Brazil, Peru, and Venezuela. M. parvidens is one of only two mammal species showing eusocial social structure similar to that found in ants, bees, or termites, the other being the Naked Mole Rat, which was thought unique in that respect until a Brazillian construction company accidentally unearthed a large nest of M. parvidens near the small coastal town of Macapa in 2002.
M. parvidens is the only mammal other than man to practice agriculture and animal husbandry, and though although similar behaviors are practiced by the Leafcutter ant and the Yellow Meadow Ant, no other animal raises both animals and plants. M. parvidens was thought to be a solitary insectivore that was only unusual in that it was diurnal, which makes it unique among the Slender Opossums of genus Marmosops. In fact, they live in complex networks of burrows that extend as deep as 15 meters below ground, the vast majority of the colony never leaving the nest.
There have since been several large M. parvidens nests discovered, the largest of which was home to an estimated 4000 opossums. The inhabitants of the nests appear to be divided into three castes. Each nest has 1-4 fertile females that remain deep underground and are fed by the much smaller males that make up the majority of the nest's population. They have the shortest gestation period of all mammals, giving birth every 11 days to 10-20 young. Delicate Slender Opossums exhibit a large degree of sexual dimorphism. The fertile females are the largest, weighing up to 800 grams and measuring 30 centimeters in length. Approximately one in ten young are born female but the vast majority are reproductively suppressed via pheromones secreted by the fertile females, and these are considerably smaller, usually no more than 400 grams and 20 centimeters in length. The males are only 50-100 grams.
The true nature of the Delicate Slender Opossum was unknown for over 70 years because they very rarely leave their nests, the most common reason for doing so being to recover the occasional mealworm or aphid that somehow escapes the nest. M. parvidens cultivates a specialized fungus that grows on their regurgitated feces, milk from the infertile females, and vegetable matter gathered from plant roots. Their symbiosis also extends to a local species of the darkling beetle which lays it's eggs in balls of fungus that the opossums periodically roll to the surface. The eggs are then returned to the nest where the larval form are allowed to grow to their pupal stage, at which time all but the largest are eaten. Those that remain are herded out of the nest when they reach adulthood. The opossums also keep honeydew producing aphids to supplement their diet. The infertile females eat a disproportionately large amount of food, but they produce milk for the young of the fertile females and the adult worker males.