"October is mating season, so they could be a little restless," the tour guide says.

She cautions us not to open our bag or stare the monkeys in the eye.

But there are monkeys everywhere as soon as we step foot in Wulongkou scenic spot in the northeast of central Henan province's Jiyuan city-It's home to the biggest troop of monkeys in northern China.

Some of them are sitting at rest on stone pillars, some scratching each other's back, and some fighting each other for the limited food visitors are throwing at them.

Despite the tour guides warnings, some visitors are taking turns having their photos taken as monkeys climb all over them.

"Those monkeys are macaques, but they are unique as they have big double-lidded eyes," the tour guide says.

"Their tails are 0.2 meters long when they are born, and they will grow thicker as they age, but they won't grow any longer."

Most of monkeys are 0.5 meters high and weigh 10 kilograms, with a life expectancy of about 40 years.

Wulongkou scenic spot was founded in 1982 for those monkeys, which are now under state protection, she says.

As we walk deeper into the scenic spot, more monkeys come into view, they all seem to follow a man in red, as he throws a bunch of peanuts from time to time. "He's Kuang San'ao, the king of all monkey kings here," the tour guide says.