A group of 18 Bolivian squirrel monkeys, who live in a no barrier enclosure, are the culprits.
“We’ve found Ray-Bans and aviator sunglasses already and with more good weather approaching we think it’s a good idea to train the monkeys not to pinch people’s sunglasses," said Mammals South Team Leader Tracey Lee in an article on the London Zoo
“They don’t like the taste of anything sour so we are going to put bitter apple on the sunglasses - we hope this will be enough to keep visitors’ eyewear safe this summer.”
The five youngest monkeys, who are about a year old , are fondest of the glasses.
"The little ones are very inquisitive," the BBC
quoted Kate Sanders, a keeper at the zoo, as saying. "They are attracted to the shiny lenses on the sunglasses.
"Once they get hold of a pair they all race round the enclosure chasing the monkey with the glasses. They've grabbed around seven pairs so far."
She said that after one of the animals gets a new pair of sunglasses, others chase them around to see what they have.
In 2006 monkeys at the zoo, attracted to the lights and noises, were stealing mobile phones
when visitors tried to use them to take their photos. That behaviour was discouraged when keepers put sticky substances on old mobile phones and let them take them.
The Bolivian squirrel monkey
is native to the rainforests of South America. They weigh 365 to 1135 grams
(12.85 to 39.95 oz), eat mainly insects and fruits, and can live as long as 30 years.