File this under bizarre stories that you couldn't make up: Calvin Klein's Obsession for Men fragrance is a favorite among the big cats.

The discovery came in 2003, when Pat Thomas, general curator for the Wildlife Conservation Society's Bronx Zoo in New York, experimented with spritzing two dozen fragrances around the habitat of two cheetahs.

The idea wasn't unusual, as zoo keepers have long sprayed fragrances on rocks, brush and toys so fenced-in animals could remain curious and entertained by their surroundings. But no one had previously taken a scientific route like Thomas, who measured and recorded how long it took the cheetahs to find the fragrance, and how much time they spent sniffing and lingering over it.

There was a stand-out winner.

While Estée Lauder's Beautiful only held attention for two seconds and Revlon's Charlie squeaked out 15.5 seconds, the sexy Obsession for Men enraptured the big cats for a record 11.1 minutes. Experts say that's even longer than the animals take to enjoy dinner.

The results spread like fire through the Wildlife Conservation Society's international network, so that countless zoos and in-the-field researchers began using the fragrance for experiments and discoveries in the field of wildlife biology.

WATCH CHEETAHS' REACT TO CALVIN KLEIN OBSESSION FOR MEN


For example, a jaguar experiment conducted in the tropical forests of Guatemala saw a breakthrough when fragrance-spritzed cameras titillated the otherwise reclusive cats into walking out in the open so that their species could be more closely observed and counted. Three times as many jaguars approached the cameras, and lingered nearby afterwards to savor the scent of the fragrance.

The scent is such a powerful attractor for the cats that Thomas originally stalled on sharing the findings, worried that poachers would use the fragrance for illegal and cruel purposes.

But after contemplation, Thomas decided that the potential good that could come from sharing the knowledge outweighed the risk that poachers could use it to kill the cats -- as it is, many of them already use the bait of dead animals to lure prey in.

So what is it about the fragrance that is seducing the big cats?

"It's a combination of this lickable vanilla heart married to this fresh green top note - it creates tension," Ann Gottlieb, who helped create the original fragrance, told The Wall Street Journal.

The scent also has contains synthetic primal notes like the musky civet, a fragrance that is secreted by the sleekly spotted large civet cat.

'It sparks curiosity with humans and, apparently, animals," adds Gottlieb.

Calvin Klein has never sponsored any of the studies, and researchers actually have difficulty finding bottles of the feline-loved fragrance, as shops near the rainforest rarely carry it, and the $60 price tag is a steep one for researchers to shell out continuously.

As for the Bronx Zoo, they depend on donations to maintain their supply, which the cats sink through quickly.

Talk about a high-maintenance pet.

Here are the scents that have us roaring this season.