Eighty-nine Mexican free-tail bats were shot and left to die in an abandoned mine shaft near the Peralta Trailhead of the Superstition Mountains, authorities said Wednesday.

"This is a blatant example of disrespect for wildlife, and the laws that are established to protect the state's wildlife," Arizona Game and Fish wildlife manager Dana McGehee said in a statement. "Unlawful killing of any wildlife is considered a major loss for the residents of Arizona and our wildlife resources."

Authorities believe the bats were shot and left to die sometime between April 1 and Friday, and they are offering a $2,500 reward for information leading to suspects.

"We need help from the public to catch the suspects," McGehee said. "If you were in the area recently, please try to recall anything you might have seen or heard, or any conversations you may have had. Someone may not realize he or she has the key to solving this case."

Mexican free-tail bats are one of 28 species found in Arizona, Game and Fish officials said.

They are considered one of the most abundant mammal species in North America and are not protected by the Endangered Species Act. However, they are considered a "species of concern" because populations in some areas have experienced dramatic declines largely attributed to use of pesticides.

According to Bat Conservation International, Bracken Cave near San Antonio has an estimated 20 million bats that consume an estimated 200 tons of insects a night.

Mother bats leave their young in the cave to hunt food at night and are able to recognize their pups from all the others by their distinct cries.