The final line of defence in Parliament against the monkey menace in New Delhi is, believe it or not, a bunch of men impersonating a different monkey species to scare them away. This was revealed by Urban Development Minister Venkaiah Naidu in response to a question in Parliament.

Forty men have reportedly been hired to make screeching noises similar to those of black-faced langur monkeys, to frighten red-faced macaque monkeys away from government buildings.

This may sound comical, but in reality macaque monkeys are a public nuisance in Delhi. It is estimated that 30,000 of these small monkeys roam the streets of the capital, trashing gardens and offices and attacking people for food.

They are, however, intimidated by the larger langurs, so Delhi's civic authorities earlier used real langurs to keep monkeys away from the parliament complex. Until last summer, monkey catchers and their trained langurs were available on hire to keep monkeys at bay.

But a year ago the administration began enforcing a Supreme Court ruling against keeping langurs in captivity as they are a protected species. The New Delhi Municipal Corporation (NDMC) cancelled its contracts with around 30 monkey catchers, resulting in a jump in monkey-related complaints.

According to the Wall Street Journal, the municipality has now outsourced the policing of monkeys to a contractor and identified 40 important buildings that need protection, including Parliament and the homes of ministers.

The “very talented” group of men imitate the whoops and barks of langurs and hide behind trees to ward off monkeys, NDMC officials told the BBC. They earn between Rs. 6,000 ($99) and Rs. 9,000 ($148) a month.

Novel as this may sound, humans aping langurs to scare monkeys isn’t an entirely new phenomenon. Punjab University had hired a dozen impersonators to protect its campus last year.

Yet it is not clear if the new monkey guards are as effective as the originals. “It can take an hour or more for the monkeys to get scared away,” a Delhi city official told the WSJ. “They don’t get scared easily.”

Other measures are reportedly being taken to reduce the monkey population. The country’s Central Zoo Authority is working on a pilot project with the National Primate Center in California to leave contraceptives in food and to sterilize captured monkeys in the northern state of Uttarakhand.

According to GlobalPost, the NDMC is also negotiating with an Indian company to supply electric shock tape for government buildings. Avi-Simian Shock Tape runs off a simple main socket, and its makers claim that monkeys and birds receive a small electric shock when touching the aluminium wires in the tape.

For now, though, the low-tech option seems to be the preferred one. Somewhere in Delhi, one of forty men is probably barking at a monkey.