LiLou the pig is the newest member of the San Francisco International Airport’s "Wag Brigade," a group of therapy animals helping to alleviate passengers of their stress. Sy Montgomery joined Boston Public Radio on Wednesday to speak about the phenomenon of therapy pets.

Therapy animal groups are spreading in airports across the country, Montgomery said.

"Alas at Logan, where we desperately need such a thing, we have nothing," she said. "But LAX has Pets Unstressing Passengers (PUP) and Denver has Canine Airport Therapy Squad (CATS)."

Having a pig join the squad in San Francisco is a wonderful addition, Montgomery said.

"LiLou is so talented, she can even play a toy piano with her red manicured hooves," she said. "The way you can tell if LiLou is enjoying herself is look at her tail, because they wag their tails just like dogs."