Scientists will count endangered kangaroo rats via satellite

FRESNO, Calif. -- Scientists plan to use satellite photos to count Giant Kangaroo Rats, the first-ever monitoring of an endangered species from outer space.

Scientists will examine images taken from the same satellite used by Israeli defense forces to find the circular patches of earth denuded by the rats as they gather food around their burrows. From that they plan to get the first-ever accurate population count of the rodents, a bellwether for the health of a parched plains environment.

By comparing the photos to 30 years of satellite images being released this month by the U.S. Geological Survey, researchers hope to better understand how the population has fluctuated in response to climate change and as the arrival of state and federal canal water turned the arid San Joaquin Valley into a patchwork of intensely cultivated farms and forced Giant Kangaroo Rats to concentrate on higher ground.

The information will help scientists determine when cattle might be used to reduce nonnative grasses, allowing the rats to more easily find food.

This study using satellite technology is taking place on the vast Carrizo Plain, a 390-square-mile desert grassland 150 miles southwest of here that is home to the most concentrated remaining populations of kangaroo rats.

The technology replaces trapping and tedious airplane fly-overs as a means of taking census.

"It allows us to more quickly recognize whether populations are declining where we want them to exist," said Scott Butterfield, a biologist with of The Nature Conservancy. "If they go below a threshold, that is when we would consider intervening."

Giant Kangaroo Rats, nocturnal rodents so named because they hop on back legs, adapted to their desert environment by extracting moisture from seeds and in their nasal passages from the humid air they exhale. For food, they pile seeds from native grasses in circles outside their burrows, which provide shelter for the endangered San Joaquin antelope squirrel and blunt-nosed lizards. Their fat five-inch bodies are a favored source of food for the endangered kit fox.