Dogs humping pillows (or other objects) is perhaps one example of risqué animal behaviour that we may be familiar with. However, according to the PDSA, this isn’t always sexually motivated.
But studies have discovered that species from around the animal kingdom engage in masturbation – and not just for fun. In the wild, masturbating can be costly in time and energy. But as it turns out, it provides plenty of reproductive benefits.
- Do animals enjoy sex? The species seeking pleasure as well as procreation
- Why do so many organisms have sex?
A 2023 study researched masturbation in primates, and found that young chimpanzees would fashion DIY sex toys from bits of chewed-up fruit, female Celebes crested macaques slapped their hinds while inserting their fingers into their vaginas, and male baboons masturbated while watching female baboons with large prosthetic bottoms (attached by researchers to replicate the swellings females develop during the most fertile period of their cycle).
The researchers discovered that the behaviour occurred in all age groups, in both males and females, and in the wild and in captivity. They also concluded that it was likely that the ancestor of all monkeys and apes (including humans) masturbated – rather than it being a habit picked up across species.
As well as speeding up mating times (ideal if you’re a low-ranking male that might get interrupted part-way through), masturbation allowed males to replenish their semen with newer, high-quality sperm – increasing the chances of reproductive success.
A similar tactic is also employed by marine iguanas. During the mating season, smaller male iguanas are more likely to get pushed off females by larger rival males. To improve their chances of reproductive success, the smaller male iguanas masturbate and store their semen in a hemipenis pouch. They then transfer this to the female’s cloaca. In a 1996 study, this method was found to increase the mating success of small males by 41%.
Masturbation has also been documented in birds, with a 2026 study concluding that the behaviour is “healthy, natural and widespread”. The research team found that it was more common in species with multiple mates and suggested that female masturbation in birds could increase the likelihood of producing more offspring.
