LOS ANGELES (AP) >> The public can once again get a close look at scientists working to uncover the bones of saber-toothed cats, mastodons and mammoths in the heart of Los Angeles.

Officials at La Brea Tar Pits are reopening a shuttered exhibition hall and reactivating an excavation site, allowing visitors to look on as workers dig for prehistoric fossils from a pool of naturally occurring asphalt called Pit 91.

The expanded offerings at the George C. Page Museum, which oversees fossil collections at the tar pits, are meant to make more accessible the science of paleontology and what it can tell us about current issues such as global warming.

"These fossils are a wonderful resource for telling us about the climate change in the past," the museum’s chief curator John Harris said.

In late June, the museum will resume free tours of the observation pit, a round mid-century building behind the nearby Los Angeles County Museum of Art. The sunlit hall brings visitors down spiral steps to see the bones of horses and camels trapped in natural asphalt.

Of the five million fossils uncovered at the tar pits, almost a million came from Pit 91. Scientists halted digging there in 2007 to focus on a trove of fossils unearthed during a nearby construction project.

All summer at Pit 91, two paleontologists will sink their trowels into the sticky asphalt, searching for bones and shells, while visitors can watch from a viewing deck. After plucking out bones that are easily visible, the workers will send buckets of goo to a lab where researchers will clean and sift out specimens of insects and plants.

These so-called microfossils "paint the picture best of the ancient climate that prevailed here in our city," said Luis Chiappe, a curator at the Natural History Museum of Los Angeles County.

From rare fossils found in Pit 91, researcher Anna Holden said she was able to gauge the type of climate that the leafcutter bee prefers. With farmers today grappling with the collapse of the honey bee population, Holden said her climate analysis could inform the agriculture industry as it switches over to different types of bees like the leafcutter.

Most of the museum’s excavators are still working on Project 23, an effort to recover fossils found during the construction of a nearby underground garage.

"We dig for buried treasure," said one of Project 23’s full time excavators, Laura Tewksbury, as she used a dental pick to uncover a mouse’s bone.

Visitors must watch the Project 23 team from behind a fence. Tewksbury said she enjoys the crowd.

"That’s part of actively working in Los Angeles — we want them to gawk," Tewksbury said.