Backstory: Monkey see, monkey dial

"...Life in this Big Smoke isn't 2 bad. There R trees to swing in and lots a insects 2 eat. I have 11 friends 2 play with, so I'm never lonely. Gotta dash, feeding time! Luv and..."

What would a squirrel monkey want with a cellphone? It sounds like the setup to a Jay Leno line. But, in fact, serious scientists at the London Zoo have been wrestling with this zoological mystery for months.

Twelve of the tiny, agile monkeys that come from Latin America moved into the zoo a year ago, and immediately began to cast their beady eyes - and occasionally get their miniature mitts - on visitors' cellphones.

Maybe it's a case of the animal kingdom trying to tell humans that the technology revolution has gone too far. Or a message to teens that parents seem incapable of delivering: Get off the phone! More likely, say officials who get paid to think about these things, the reason is much less Machiavellian.

"We think they were attracted by the flashing lights and ring tones," says Jo Cook, a mammal expert at the zoo.

The mischievous monkeys live in a barrier-free enclosure that visitors can walk through. Amid imposing trees connected by ropes, they come face to face - and, it seems, hand to cell - with the humans who come to gawk at them. Forget monkey see, monkey do. This is a case of monkey see, monkey dial.

Though their exact reason for doing it may be unknown, Aoife Doyle has a theory. "It's obvious - they want to phone home, like ET," says the 12-year-old, who is visiting the zoo with her family. "They miss their friends back in Bolivia and might be worried that some have been poached to become pets." Aoife has clearly been paying attention to the information signs.

"No, they wanna send a text message," interjects her 10-year-old brother, Steven. "Look at their little hands, perfect for texting."

Overhead, one of the monkeys hangs from a branch by its tail and use its hands to grab a squirming grub. It is hanging hands-free. "Yeah, they can swing and SMS [short message service] at the same time," notes Steven.

"...We're settling in well. It's not 2 different from home - warm and leafy and bristling with juicy creepy crawlies. But there R strange uprite creatures who stare at us during the day and then disappear again at nite. Weird..."

Squirrel monkeys are cute and comical. They range in length from 10 to 14 inches, and their tails can grow to 16 inches. Fringed with orange-yellow fur, the creatures are spectacularly speedy, scuttling up tree trunks and leaping from one branch to another like, well, squirrels. Hence the name. They traverse treetops using all four limbs and can leap up to 23 feet.

They are the smallest and among the most curious of the primates. Only 3,500 of them remain in the wild, their numbers threatened by poachers seeking to sell them for use in biomedical research or as pets or bait.

The year-old enclosure at the London Zoo, spanning 4,900 square feet, is done up to look, feel, and smell like the rain forests of Bolivia, where these cheeky monkeys come from. It is surrounded by fencing, but it is open to the skies. The trees and plants were chosen for their scent and because they bear the sorts of fruit that squirrel monkeys like to snack on in between the serious business of making a meal of insects and grubs.

But there is, of course, one big difference between this corner of north-central London and Bolivia: the presence of people. What's more, the people carry around strange black and silver ringing objects. And, as we know, these objects tend to double as cameras these days, which means that many visitors were leaning down to photograph or film the monkeys, holding their cells up close to their faces.

"The monkeys must have thought it was a case of the 'phone's for you,' " says Ms. Cook.

To be sure, the squirrel monkeys seem comfortable living in an open enclosure with people milling around. They're bold and not easily spooked. Even the garish balloons and toy Komodo dragons kids carry around don't seem to unnerve them. Cellphones, however, are another matter. Whether it's curiosity or the possibility of free nighttime minutes, the monkeys would transform into furry thieves, leading to impromptu tugs of war between man and beast. With their tiny hands, the monkeys mainly lost. But those that did manage to make off with a cell tended to discard it shortly afterward.

"We want this to be a natural habitat for them," says Cook. "And there was something unnatural about their interest in cellphones."

As a result, animal behaviorists went to work to curb the illicit impulse. Their solution ... mustard.

"...I'm getting strange looks l8tely. U'd think they had never seen a monkey msging b4. MayB they don't want us getting homesick. And there seems 2 B sumthing wrong with this phone...."

Over three weeks, zoo staffers dressed up in what Cook refers to as "civilian clothing" - jeans, sneakers, and T-shirts - rather than their easy-to-recognize brown uniforms. They walked through the squirrel monkey enclosure with the rest of the visitors, armed with broken cellphones. They offered them to the curious monkeys, who, of course, accepted. Bad move. These were cellphones with a difference.

"We put sticky substances on the phones that squirrel monkeys don't like," says Malcolm Fitzpatrick, the curator of mammals at the Zoological Society of London who devised the gooey cellphone plot. "We wanted to teach them not to touch the phones, and we know they don't like anything sticky."

The substance turned out to be mustard because, as Cook says, "They hate mustard."

The idea wasn't to punish the animals, but to reduce the impact of humans on their natural behavior by training them to ignore cells. "It's back to business as usual now," says Cook, although she thinks the exercise may have to be repeated in a few months - squirrel monkeys don't have long memories. "But for the time being they are doing what squirrel monkeys always do - sleeping, leaping, and foraging for insects. Even the loudest ring tone doesn't really interest them anymore."

"...These cells R overrated. Who wants a device that buzzes and bleeps and is covered in yukky stuff?? The uprite lot can keep 'em."

Back in the enclosure, Aoife and Steven watch a couple of squirrel monkeys dart across a rope from one tree to another, more impressively than the most talented tightrope walker. A woman leans down to film a foraging monkey with her cellphone.

He stares at it for a bit, seems to grimace, and then carries on digging the dirt. This is one primate that has apparently decided cellphones are more of a hassle than they're worth, with or without a weekend calling plan.