{"id":7041488,"date":"2026-08-18T23:27:27","date_gmt":"2026-08-18T23:27:27","guid":{"rendered":"https:\/\/peraltafinancing.com\/aerospace\/do-monkeys-keep-pets-study-finds-widespread-primate-interactions-with-other-animal-species-from-mice-to-deer\/"},"modified":"2026-08-18T23:27:27","modified_gmt":"2026-08-18T23:27:27","slug":"do-monkeys-keep-pets-study-finds-widespread-primate-interactions-with-other-animal-species-from-mice-to-deer","status":"publish","type":"post","link":"https:\/\/fivemor.com\/?p=7041488","title":{"rendered":"Do Monkeys Keep Pets? Study Finds Widespread Primate Interactions With Other Animal Species, From Mice to Deer"},"content":{"rendered":"


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This social behavior might reveal the evolutionary roots of traits that underlie pet-keeping in humans, scientists say, from caregiving to tolerance and curiosity. But it\u2019s not the same as a person keeping a cat or a dog<\/h2>\n
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Carlyn Kranking<\/a><\/p>\n

| Associate Web Editor, Science<\/span><\/p>\n

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A tufted gray langur strokes a grizzled giant squirrel in Yala National Park, Sri Lanka.
\n Senthi Aathavan Senthilverl via Grueter et al., Primates<\/em>, 2025, under CC BY 4.0<\/a><\/span>
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When a mouse wandered into the white-cheeked gibbons\u2019 enclosure in the Shanghai Zoo, the monkeys didn\u2019t try to eat it\u2014or even chase it away. One female primate scooped up the rodent and gently held and caressed it. University of Oxford evolutionary biologist Cyril Grueter<\/a> watched the interaction, and he was mystified.<\/p>\n

\u201cI wasn\u2019t quite sure what I was looking at,\u201d he wrote in an article for the Conversation<\/a><\/em>. \u201cThe gibbon treated the tiny rodent with remarkable gentleness. I couldn\u2019t stop wondering why.\u201d<\/p>\n

Working with an international group of researchers, Grueter then uncovered more examples of primates interacting closely with other species. A young male bonobo carefully cradled<\/a> a mongoose pup. Some monkeys climbed onto the backs of pigs; others mounted deer<\/a>. A tufted gray langur<\/a> stroked a squirrel<\/a>. A group of stump-tailed macaques worked together to groom a stray dog.<\/p>\n

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A group of stump-tailed macaques groom a domestic dog at Khao Tao Mo temple in Thailand.<\/p>\n

Neil Challis via Grueter et al., Primates<\/em>, 2025, under CC BY 4.0<\/a><\/span><\/p>\n<\/figcaption><\/figure>\n

In all, the team tallied 427 cases from scientific papers, media reports and a global survey of 37 primatologists. The interactions, most of which included play or grooming, occurred both in the wild and in captivity. They involved 88 primate species alongside 127 other species. The researchers published the findings in July in the journal Primates<\/a><\/em>.<\/p>\n

The compilation reveals that \u201cthis is quite a common behavior,\u201d Grueter tells New Scientist<\/a><\/em>\u2019s Michael Marshall. The new work is only a first step, but it\u2019s starting to fill a void on the subject in the mainstream scientific literature, he adds. \u201cWe\u2019re hoping that this study is also a wake-up call for primatologists, or zoologists more generally, to look for similar behaviors in both the wild and in captivity.\u201d<\/p>\n

One of Grueter\u2019s favorite encounters occurs in Japan, where macaques have been regularly seen grooming and riding on the backs<\/a> of sika deer. \u201cIt starts with something mundane: Macaques feeding in trees drop fruit and leaves that deer eat, and deer also consume macaque feces around sleeping sites,\u201d C\u00e9dric Sueur<\/a>, an animal behavior researcher at the University of Strasbourg in France, tells Smithsonian<\/em> magazine. But it doesn\u2019t stop there: \u201cMacaques groom deer and eat their parasites, play with them and ride them<\/a>.\u201d They even try to mate with the deer, a behavior that might be spread through social transmission<\/a> among the primates.<\/p>\n

Sueur has published studies<\/a> on the macaques and deer, but he was not involved in the new research. With the team\u2019s assembled anecdotes, he says, \u201cscattered curiosities become a dataset one can interrogate.\u201d But he emphasizes that the observations were not a designed experiment. \u201cThe numbers describe where scientists and cameras have been, not how often these behaviors occur,\u201d Sueur says.<\/p>\n

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A female northern white-cheeked gibbon holds a mouse at the Shanghai Zoo.<\/p>\n

Cyril Grueter via Grueter et al., Primates<\/em>, 2025, under CC BY 4.0<\/a><\/span><\/p>\n<\/figcaption><\/figure>\n

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A Japanese macaque rides the back of a sika deer at Yakushima, Japan.<\/p>\n

Alexandre Bonnefoy and C\u00e9dric Sueur via Grueter et al., Primates<\/em>, 2025, under CC BY 4.0<\/a><\/span><\/p>\n<\/figcaption><\/figure>\n

Not all interactions documented by the team seemed friendly. Twenty-six of the incidents were deemed \u201cabusive,\u201d though these ranged widely. In one case, a male baboon in Saudi Arabia seemed to have \u201ckidnapped\u201d a domestic puppy<\/a>, per the paper, and carried it around for long periods. The researchers identified 13 instances where the other animal died from violent handling, including birds, pangolins, primates and a domestic cat. These cases did not necessarily stem from ill will or aggression on the part of the primates\u2014some might have simply been botched attempts at caring for the other creature.<\/p>\n

Patterns emerged in how the primates interacted with other species based on their age and sex. Juvenile primates were more likely to engage in play, while females were more likely to groom. Most interactions were initiated by the primates.<\/p>\n

These reports may shed light on the evolutionary origins of pet-keeping behavior in humans, the team writes. Of course, these cross-species relationships aren\u2019t the same as humans having a cat or a dog. \u201cThe authors say so themselves: Nearly all these interactions are ephemeral, whereas keeping a pet is a durable, caretaking bond,\u201d Sueur says. But the behaviors \u201cmay represent some of the evolutionary building blocks from which human-animal companionship eventually emerged,\u201d Grueter adds in a statement<\/a>.<\/p>\n

The findings indicate that \u201csome of the behavioral capacities that make pet-keeping possible (curiosity, tolerance, caregiving and maintaining long-term relationships with another species) did not suddenly appear in humans but have deeper evolutionary roots,\u201d Grueter adds in an email to Defector<\/a><\/em>\u2019s Sabrina Imbler.<\/p>\n

A few cases, however, showed some longer-term care. A group of black-striped capuchin monkeys seemingly adopted<\/a> an infant common marmoset in Brazil in 2004. The young monkey received care from two \u201cadoptive \u2018mothers,\u2019\u201d per the paper, and tolerance from others in the group, where it remained for at least ten months. A captive western gorilla named Koko showed maternal behaviors\u2014from grooming to cradling and protective posturing\u2014toward a kitten named All Ball<\/a> in the 1980s. News reports in 2017 described<\/a> a crested macaque in an Israeli zoo cuddling, grooming and playing with a chicken that wandered into its enclosure.<\/p>\n

Next, Sueur says, he would like to see \u201cstudies that take the other species\u2019 point of view.” He adds: “Almost everything we know is measured from the primate\u2019s side; deer, dogs and pigs are treated as the setting rather than as partners.\u201d If some of these interactions, such as the primates riding the sika deer, are to be seen as shared culture between the species, then they are not one-sided. This kind of relationship, he adds, \u201conly makes sense if you watch both.\u201d<\/p>\n

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