Order : Paucituberculata
The Elusive Shrew Opossum
Found only in the Andes mountains along the western portions of South America, the Paucituberculata, or Shrew Opossums, are a family of small, mouse-looking marsupials. It was once believed that Shrew Opossums were rare, but new evidence suggests there are more of these animals about than originally thought. Due to the difficulty in reaching their native habitat, their small size and nocturnal behavior, relatively little is known about these elusive creatures.
Few Shrew Opossums have been captured for studies, and even fewer have been recaptured later for follow-up examination. Whether this is due to a short lifespan or the animal's secretive nature is unknown. Scientists do believe these tiny creatures are natural quarry for any of predators in the Andes.
Currently, little is known about the family life of Shrew Opossums. A male, female and several young were once captured in the same trap, suggesting they live in family groups, but there isn't enough evidence to definitely establish this. Likewise, questions about litter size remain, but scientists believe the females generally have 5 to 7 young per litter.
There are only six species of Shrew Opossums, and they all share similar physical appearances. They have small bodies, 9 to 14 centimeters (3.5 to 5.5 inches) in length; their tails are roughly the same size as the body, giving them a total length of 18 to 28 centimeters (7 to 11 inches.) Females are smaller than the males, generally weighing 14 to 26 grams ( one-half to 1 ounce), compared to the males' 25 to 40 grams (1 to 1.5 ounces).
All Shrew Opossums have a thick covering of fur on their bodies. This includes a less-dense covering on the tails. Fur color ranges from gray, dark brown to black, with the fur on the top of the body typically being a darker shade than the rest of the body. Their snouts tend to be pointed, and, for this reason, they are sometimes called Rat Opossums.
Although Shrew Opossums have very poor eyesight, they are active hunters. They rely on their excellent hearing and the sensitivity of their long whiskers to capture their prey. A variety of insects, worms, and small vertebrates and mollusks, along with grasses and grains, make up their diet.
There are currently only six species of Paucituberculata, although the fossil record shows there were once more. The native habitat of most Shrew Opossums cover a wide range, but the Andean Shrew Opossum can only be found in one location, the Cordillera del Condor mountain range in Ecuador, and only then at altitudes higher than 2,000 meters (6,562 feet).
All Shrew Opossums share an unusual biological trait - paired sperm. Pairs of sperm join together in the male's reproductive system and remain joined until just before fertilization in the female. It is unknown what biological advantage this behavior offers, but it common in all American marsupials.
Animals in the order Paucituberculata
|Silky shrew opossum|