Behind normally locked doors, LSU professor Van Remsen pulls open a vault to reveal the museum's valuable collection.

The visitors lean in, crane their necks and raise their phones to snap pictures … of a drawer full of black and red bird carcasses.

"This is a gold mine of data," Remsen says with a proud grin. 

These scarlet-bellied mountain tanagers, gathered throughout the Andes Mountains of South America, represent years of hard work from LSU Museum of Natural Science researchers who gathered the birds, stored their DNA and brought the carcasses — called "skins" by the scientists — back for further research. 

More than 190,000 such bird samples fill drawers and freezers and nitrogen tanks in the basement and back rooms of the Museum of Natural Science, located at Foster Hall on the north end of LSU's campus. The museum's is the third largest research collection of birds in the world. The specimens allow scientists to study the evolution of these birds and better understand the world around us. 

For a few nights this fall, the museum is opening these off-limits areas to a few members of the public through its Night at the Museum series. Scientists like Remsen, one of the country's leading ornithologists, lead curious families and science lovers through the circuitous vaults that store their research subjects. 

"We wanted people to know about that — where we are, who we are, what are we researching," says Valerie Derouen, the museum's outreach coordinator. "Why do we have all these dead animals behind the scenes?"

Many in Baton Rouge grew up visiting the free museum with Scout troops or on field trips, and they are familiar with the musty exhibit area in the old hall with Spanish-style architecture and an occasionally leaky roof. Bears and snakes stand frozen in lifelike taxidermy, and classic dioramas of nature scenes display the ecosystems of Louisiana and the United States. 

"A lot of people don’t know we exist — especially students — or only know about the public exhibits," Derouen says. "We thought this would be a really fun way to meet the scientists, understand what they are researching."

The scientists here have discovered dozens of new species of fish, birds and other animals throughout the world. Huge research institutions like Harvard and Cornell universities often borrow from LSU's vast collection of resources to further their own studies, Remsen says. 

"I didn't even know it existed," says Evelyn Johnson, 49, who came to September's tour after reading about it in the library newsletter. "This is kind of exciting."

The museum was founded in 1936 by George Lowery, an ornithologist who focused on the birds of the Gulf Coast and Mexico.

In 1955, the museum’s exhibits opened to the public. In the late 1950s and early ’60s, scientist and artist Ambrose Daigre hand-painted dioramas depicting Louisiana’s Gulf Coast prairies and virgin forests as well as more exotic rainforest and Rocky Mountain scenes.

Such dioramas were popular museum exhibits in the early 20th century, before nature videos were available at the click of a mouse, Derouen says.

“They’ve been retouched, but they are pretty much the way they looked in the ’50s,” she says.

And there's the stuffed animals, most notably a polar bear, a brown bear and the first Mike the Tiger.

In the 1960s, student John O’Neill began documenting the common, yet under-studied birds of South America, and museum researchers have since become known for their expertise on that continent. In the 1980s they began lugging tanks of nitrogen into remote mountains and jungles to store live tissue from animals to better study their DNA. 

"Because of that, we have that old school explorer discovery-type research in the field also combined with the cutting edge molecular research," Derouen says. 

Along with the back rooms, Remsen also pulls out his "top 10" specimens to share, from the huge, nearly two-foot-long imperial woodpecker from Mexico, to the smallest bird in the world, Cuba's bee hummingbird, which is about the size of your pinkie finger.

Rebekah Ayer, 35, brings her 4- and 6-year-old sons to the museum regularly. They are transfixed by the variety of colorful tropical birds Remsen shows.

"You can just take your time and look at the different animals," she says. "It’s such a highfalutin thing. I'm not sure what they take in. It might pique their interests, have a little spark.”

Researchers at the museum are excited to come out from behind the scenes to tell the public about their work.

“We need get the word out about how important the world is because we’re losing so much of it,” fish researcher Prosanta Chakrabarty said in an August interview.

Even with all the information available online today, museums offer a place to see and touch, Derouen says. 

"Museums are the only way you would learn those stories," Derouen says. "We are the record keepers of life on earth."

To learn more about the free Night at the Museum series, visit the LSU Museum of Natural Science at lsu.edu/mns/.

Follow Kyle Peveto on Twitter, @kylepeveto.