Jason Overdorf

Special for USA TODAY

NEW DELHI — On a typical afternoon in a posh neighborhood here, a troop of rhesus macaque monkeys climb the wall of an apartment building to the rooftop water tanks with a specific goal.

Swinging like circus performers until one of the water pipes snaps off, the monkeys rush to drink the spraying water.

“It happens quite often,” said homeowner Shakun Chandhok, who called a plumber after a servant used a stick to drive off the monkeys. “They used to jump into the balcony and come into the kitchen and open the fridge, just like any human being does.”

The orange or gray monkeys, which weigh 12 to 17 pounds, have become one of the most dreaded pests in India, biting around 1,000 people a day nationwide and overrunning cities like New Delhi. The monkey problem has become so overwhelming that officials are searching for ways to use birth control on the animals.

In the fruit-growing state of Himachal Pradesh, monkeys have increased more than fivefold in the past decade, according the government. The animals create up to $300 million in crop losses and diverted labor every year, the farmer’s group Kheti Bachao Andolan said.

“Wherever they go, panic spreads,” said primatologist Iqbal Malik, who runs a nonprofit called Vatavaran, which is Hindi for environment. “Residents warn each other to close all doors and windows. Any houses which get raided by monkeys (are left) in shambles — eatables on the floor, crockery broken, taps open, wires cut, plants mauled.”

Himachal Pradesh formed a task force this month to cull the animals, which officials recently declared vermin. In the neighboring state of Uttarakhand, scientists at the Wildlife Institute of India will test an injectable contraceptive that has been used on white-tailed deer and wild horses in the United States.

“What our simulation and modeling indicate is that we need to control reproduction by more than 70% of the adult female population for a very long time, eight to 10 years,” to seriously impact monkey populations, said Qamar Qureshi, a senior scientist at the Wildlife Institute involved with the injectable contraceptives program.

City and state governments have tried numerous methods to control the monkey troubles. Since the monkeys are associated with the Hindu god Hanuman, mass culling has never been attempted. Officials have tried surgical sterilization. They’ve also employed monkey trainers to bring in tame langurs — a larger, more dominant species — to scare off the macaques.

Delhi officials even hired people to impersonate langurs to keep rogue macaques out of parliament. But the impersonators couldn’t keep them out of the building for long.

Himachal Pradesh spent around $1 million to set up eight sterilization centers. Officials pay trappers a bonus of nearly $10 a head for capturing the animals. Over the past 10 years, the state has sterilized more than 125,000 monkeys.

The cost and difficulty of sterilization has prompted persistent calls for trying oral contraceptives, a proposal first suggested in 2013. Qureshi said that plan failed because it's difficult to ensure the female monkeys consume the correct dosage, plus concerns that the drugs might hurt other species.

“Using oral contraceptives is a far-fetched dream at present,” he said. “It’s very difficult to implement in the field. We’re not talking about zoo conditions, where you can feed monkeys in controlled conditions.”

Injections are more practical, and in theory could be administered more quickly, but still present challenges. A single dose lasts only one year, and after that booster shots are necessary. At nearly $100 a dose, that's too costly for widespread use in the United States, let alone in India.

Surgical sterilization is much cheaper, easier to monitor and permanent, said Mewa Singh, a primatologist at the University of Mysore. But catching and releasing the monkeys is also costly.

Adding to the multiplying monkey population in urban centers from New Delhi in the north to Chennai in the south: People feed them at temples and parks, believing them to be holy.

“In South India, we’ve been monitoring the (macaque) population for the past 25 years,” he said. “The population has come down by 66%. But the complaint is the same. There are hundreds of thousands of monkeys, and they’re damaging the crops.”