Masturbating monkeys use stones as sex toys but never climax in sanctuary

Randy monkeys have been spotted using stones as sex toys at a 'sacred sanctuary', scientists say.

Both male and female long-tailed macaque monkeys at the Sacred Monkey Forest Sanctuary in Ubud, central Bali, have found a new use for rocks.

A study led by Camilla Cenni of the University of Lethbridge in Alberta, Canada, reports female monkeys are fussier when it comes to picking out the perfect stone to pleasure themselves with.

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The article titled "Do monkeys use sex toys? Evidence of stone tool-assisted masturbation in free-ranging long-tailed macaques”, has been published in the latest issue of Ethology: International Journal of Behavioural Biology.

The Abstract reads: "Our data partly supported the “Sex Toy” hypothesis indicating that stone-directed tapping and rubbing onto the genital and inguinal area are sexually motivated behaviours."

To carry out the study, researchers looked at hundreds of video recordings from between 2016 and 2019 at the 12.5-hectare sanctuary in Bali.

Footage confirmed what the scientists predicted when conducting the study, that like humans the primates not only masturbate but use devices as physical aides too.

According to the research, males at the sanctuary like to rub or tap at least one stone on their penises, but never did it appear to end in ejaculation.

Females on the other hand could be seen pushing stones under beneath their genitals for stimulation however they were far more selective than males about their utensil.

Unlike males, adult females sought out stones with particularly rough and angular surfaces.

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The study acknowledged that learning of primates masturbating is nothing new but the use of external tools is definitely less common place.

Long-tailed macaques tapping and rubbing stones in Bali is thought to be connected to mating behaviour, as well as physiological responses, such as estrus in females and penile erection in males.