The "pygmie mouse-opposum" may look like a cartoon character, but it could be a new species of mammal, experts say.

Thomas Husband, a professor of natural resources at the University of Rhode Island; environmental specialist David Abedon; and five undergraduates found the mammal earlier this month in Sergipe, a thinly populated Brazilian state.The rain forests in Sergipe haven't been explored in 150 years, experts said.

The animal stands shorter than 3 inches, has an 8-inch tail and ears half the size of its body. It has small fingers with fingernail-like claws and makes squeaking noises.

The Rhode Island team had not expected to find much wildlife because of the clearing of rain forsests for farming. The dense foliage used to cover 40 percent of Sergipe, but farmers growing coconuts and raising cattle have burned off all but about one-twentieth of that.

To their surprise, the researchers trapped hundreds of animals, including 167 species of birds. The most unusual find was the mouse-opposum, a pouchless marsupial not described in any literature the explorers have found.