"The seals learned that, hey, if I make the same noise back, I'm going to get a fish," she explained.
Next, Stansbury and Janik used a computer to make small adjustments to the sounds, making the tones higher, and rewarded the seals for matching those new sounds. And then she strung a few of those notes together to play the songs.
"The first time that you hear them actually imitate something recognizable back, it just blows you away," Stansbury said.
Stansbury is now a zoo area supervisor at the El Paso Zoo in Texas.
She said other animals like birds and dolphins are also capable of vocal learning, but seals are unique because they have vocal chords. That might allow for insight into how mammals learn sounds, and help bring new approaches in human speech therapy.
"Unfortunately, we don't have any income coming in from this," Stansbury said. "The seals might be able to share some of their fish while they're out there, back in the wild. That's about the only royalties we're going to have for John Williams."