A search-and-rescue team pulled a half-ton rare whale fossil from a Southern California backyard Friday, a feat they are now taking on as a makeshift training session.

The approximately 16-million-year-old fossil from a baleen whale is one of about 20 known to exist, Natural History Museum of Los Angeles County paleontologist Howell Thomas said, according to The Associated Press (AP).

A group of 10 rescue workers from the Los Angeles County Sheriff's Department dislodged the fossil from a 1,000-pound boulder and hoisted it from a ravine using pulleys and a steel trolley. Location and size complicated the rescue mission, but the rarity of the find persuaded volunteers to excavate the whale fossil from the site.

Gary Johnson, 53, who first discovered the fossil as a teenager, was turned down by another local museum at the time to pull the whale from his Rancho Palos Verdes hillside. But when a 12-million-year-old sperm whale fossil was recovered at a nearby school this past January, it prompted Johnson to call the Natural History Museum.

"I thought, maybe my whale is somehow associated," he told the AP.

The fossil included fragments of the whale's jaw, skull and baleen. Baleen functions as a kind of filter for toothless whales during feeding, and is composed of a soft tissue, fingernail-like material, making it difficult to fossilize, Thomas explained.

"Baleen whales don't just grab fish individually - they actually open their mouth and they suck in a lot of small animals," he said, according to the Los Angeles Times. "That actually gives them the capacity to grow large because they're eating a large quantity of small animals at one time. They're filter-feeders."

The rare find will be added to the county museum's collection of baleen whale fossils.

And volunteer crew will now have an interesting story to tell. They typically rescue stranded hikers and motorcyclists who careen off the freeway onto steep, rugged terrain, search-and-rescue reserve chief Mike Leum said.

"We'll always be able to say, 'it's not heavier than a fossil,'" Leum told the AP.