A baby monkey, whose naming by a Japanese zoo as Charlotte after Britain's newborn princess caused something of an uproar, is in full tomboy mode.

The 3-month-old, 15-cm-tall macaque from Mount Takasaki Wild Monkey Park in Oita has become a sensation with park visitors as she messes around with the other monkeys in the troop, making lovable gestures and funny faces.

"She's our poster girl right now," said one zoo official.

She is still being nursed but isn't afraid to venture off on her own to play on the slides or jungle gym.

"She's not afraid of anything and curious about everything," said the person in charge. "She's even accidentally fallen (in) when she gets too close to the monkey pool."

The zoo, located in southwestern Oita, named the monkey Charlotte in May after Princess Charlotte Elizabeth Diana was born to Prince William and his wife, Kate, earlier the same month.

But a flood of complaints followed from people who thought naming a monkey after the princess disrespectful. The zoo had considered renaming the monkey, but the city of Oita decided to stick with Charlotte since it never received a complaint from the British royal family.

Many visitors often ask for Charlotte, and a postcard that went on sale this month with her photo is also a big hit.