By John McDevitt

PHILADELPHIA (CBS) — Some may consider bats one of Halloween’s creepiest creatures. Others think they’re kind of cute and important for the ecosystem .

There are more than 1,000 different species in the world with 40 species of bats found in the United States.

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Seventy percent of bats consume insects like mosquitoes making them nature’s exterminator. While some bat populations number in the millions, others are dangerously low or in decline.

The Rodrigues Fruit Bat would d most likely be extinct if it wasn’t conservation efforts started by the Philadelphia zoo around 1990’s.

Kim Lengel is Vice President of Education and Conservation at the Philadelphia Zoo. She did her graduate work back then on the tiny island of Rodregues in the southern Indian ocean where the bats are from.

“They went from less than 100 to 20,000 and now they are no longer critically endangered,” she said. “I was and it so exciting I got a chance to save a species”

And tis the season, October happens to be bat appreciation month.

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So why are bats associated with Halloween?

“I don’t know probably because people think they turn into Vampires,” said eighth grader Natalie Alexander of St. Patrick School in Malvern.

They don’t?

“No,” Natalie said laughing. “There is one called a vampire bat, but they don’t actually turn into vampires.”

The Philadelphia Zoo has about 30 vampire bats with three newborns less than a week old. They do feed on blood though, and the zoo purchases cow blood for the bats from a Penn State livestock and cattle club.

Also part of the zoo’s conservation education here at the Philadelphia zoo the extinction grave yard where animals that once roamed the earth are remembered like the DODO bird last seen in 1681.

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Halloween fun is expected this weekend for the “Boo at The Zoo” where kids can come in costume and get treats and maybe learn some things like conservation.