Cotton-top tamarins grew calmer after they heard music compositions based on their own calm, friendly calls. But the monkeys became more agitated when University of Wisconsin-Madison psychology professor Charles Snowdon played music that contained elements of their own threatening or fearful calls. ?UW-Madison University Communications 608/262-0067 Photo by: Bryce Richter Date: 02/08 File#: NIKON D3 digital frame

If you want to mellow out a monkey, play him some Metallica.

That’s the surprising result of a new study by Charles Snowdon, a
University of Wisconsin-Madison psychology professor. The researchers played clips of music— including Metallica’s
“Of Wolf and Man,” Nine Inch Nails’, “The Fragile,” Tool’s “The
Grudge,” and Barber’s “Adagio for Strings”—for cotton-top tamarins.

Humans generally find the Nine Inch Nails and Barber pieces to be calming, with their slow tempos and descending pitches, like sighs. The Tool and Metallica songs, in contrast, tend to make people feel excited, as a result of their faster tempos and machine-gun bursts of

The monkeys, however, barely responded to any of the pieces, though they did seem to calm down and relax a bit while listening to Metallica and Tool.

“I don’t have a good explanation for that,” says Snowdon. “They are usually very active animals, and their movement got minimal after they heard those two pieces.”

The practical upshot? Monkey keepers may want to play heavy metal rather than classical music to calm their colonies. However, they’d do even better if they played “monkey music” — pieces composed specifically for tamarins by study co-author David Teie, a University of Maryland cello instructor and member of the National Symphony Orchestra.

Teie mimicked the contours of tamarin calls and wrote songs that had a muchbigger effect on the animals’ behavior than human music did. One piece, with a slowly rising whistle-like melody, caused the monkeys to groom one another and engage in other leisurely, social activities. Another, with short, staccato notes, sent the animals into a frenzy of anxious behavior including scent marking and head shaking.