A fascinating study reveals that selectively bred mice show playful behaviour toward humans, while golden hamsters prefer interacting with their own kind, offering new insights into the science of animal emotions, communication, and social bonding.
Have you ever wondered whether a tiny mouse can enjoy playing with a human, or whether a hamster prefers playing with another hamster instead? Although playful behaviour is commonly observed in pets such as dogs and cats, scientists still know relatively little about how smaller rodents interact socially with humans.
Social play is much more than simple entertainment. It helps animals develop physical abilities, learn communication skills, strengthen social relationships, and understand the behaviour of others. Previous research has explored these activities extensively in rats, but similar studies involving mice and hamsters have been limited.
To investigate this unexplored area, Sarah Dagher and her research team studied two small mammals: selectively bred tame mice and golden hamsters. They compared how these animals behaved when interacting with humans and members of their own species.
Their findings revealed a fascinating difference. Tame mice showed increased playful behaviour toward humans, while golden hamsters displayed a stronger preference for interacting with other hamsters. The research also found that both species changed their vocal communication depending on whom they were playing with.
Why Is Social Play Important for Animals?
Social play is widely observed in mammals and other animals, including dogs, cats, birds, and rats. It often involves chasing, wrestling, jumping, gentle biting, and other repeated movements that do not serve an immediate practical purpose.
According to a widely used scientific framework, play is generally voluntary, repeated without being completely rigid, and different from behaviours performed solely to meet an immediate need. It usually occurs when an animal is not experiencing severe stress.
For young animals, play can act as a natural training ground. Chasing and wrestling help improve coordination, while interactions with other animals provide opportunities to learn social signals and respond to different situations.
Play may also contribute to emotional well-being. Research suggests that the brain's reward systems, including pathways involving dopamine and endorphins, help make social play enjoyable and reinforce positive social experiences.
These processes can encourage animals to seek out familiar partners and develop stronger social bonds. However, the way animals express play can differ considerably depending on their species, environment, and previous experiences.
The Experiment: Can Mice Learn to Enjoy Human Interaction?
One of the most interesting aspects of the study was its investigation of tame mice.
The researchers used a special population of wild-derived mice that had been selectively bred for active tameness. These mice came from a population created by crossing eight wild mouse strains. Over several generations, researchers selected animals that approached a human hand more quickly.
Within 12 generations, the selected groups showed significantly greater active tameness than unselected control groups.
This approach allowed scientists to investigate whether selecting mice for their willingness to approach humans could also influence their playful responses.
The researchers examined how the mice behaved during human interactions, including playful hand movements resembling tickling. They also studied how the animals interacted with other mice.
The results were striking. Tame mice showed more human-directed play, including chasing the experimenter's hand and producing increased vocalisations. They also engaged more frequently with other mice and displayed elevated ultrasonic vocalisations during social interactions.
In contrast, the unselected control mice showed more aggressive behaviour.
These observations suggest that selecting animals for tameness may influence more than their willingness to approach humans. It may also affect other aspects of their social behaviour, including their tendency to engage in playful interactions.
However, the findings do not establish that every tame mouse enjoys human contact or that selective breeding for tameness automatically produces the same response in all mice.
Why Do Hamsters Behave Differently?
Golden hamsters offered a contrasting picture.
Although hamsters are popular pets, their social interactions with humans have received less scientific attention than those of some other domesticated animals. They are nevertheless known to display playful behaviours with members of their own species under appropriate conditions.
In the study, hamsters showed little interaction with human hands. Their vocalisations also did not appear to be associated with contact with humans in the same way as the vocalisations observed in tame mice.
However, when interacting with other hamsters, they displayed recognisable playful actions, including boxing and pinning.
These movements can look like fighting, but their meaning depends on the surrounding behaviour and interaction. Boxing or pinning alone should not automatically be interpreted as play, because similar movements may occur during aggressive encounters.
The researchers observed that hamster play with their own species was accompanied by frequent vocalisations. This suggests that hamsters communicate differently during social interactions with other hamsters than they do during encounters with humans.
The findings highlight an important point: animals that appear similar in size or are both kept as pets may have very different social preferences.
Animal Sounds Reveal More Than We Can Hear
Another fascinating discovery involved ultrasonic vocalisations, which are sounds produced at frequencies beyond the normal range of human hearing.
Mice and hamsters can produce vocal signals that are difficult or impossible for people to hear without specialised equipment. These sounds can provide researchers with valuable information about animal communication during social encounters.
In this study, vocalisation patterns differed between interactions with humans and interactions with members of the same species.
Tame mice produced increased vocalisations during human-directed play, while both mice and hamsters showed vocal activity during certain interactions with their own species.
The differences suggest that animal vocalisations are influenced by social context. A sound produced during play with another animal may not have the same pattern or significance as one produced during interaction with a human.
Nevertheless, vocalisations alone cannot prove that an animal is happy or enjoying an interaction. Scientists must interpret them alongside movement, approach behaviour, avoidance, aggression, and other indicators of the animal's condition.
Combining these different measurements provides a more reliable understanding of animal behaviour than relying on sound alone.
What Do These Findings Tell Us About Evolution?
The study raises important questions about how social play develops and why it differs between species.
Selective breeding appears to have influenced human-directed play in the mice examined by the researchers. This suggests that traits associated with human friendliness may be connected to broader changes in social behaviour.
The hamster findings, meanwhile, demonstrate that playful interaction with members of the same species does not necessarily translate into an interest in playing with humans.
These differences may reflect distinct evolutionary histories, social systems, and ecological needs. Animals evolve behavioural strategies that help them survive and reproduce in their particular environments.
However, the research does not establish a single evolutionary explanation for these differences. Further studies involving additional species, larger populations, and genetic and neurological measurements will be needed to understand the underlying mechanisms.
Why This Research Matters
Understanding animal play is important for both scientific research and animal welfare.
The findings could help researchers investigate the genetic and neurological mechanisms associated with tameness, social motivation, and human-animal relationships. They also suggest that standard laboratory mice and selectively bred tame mice may respond differently to the same human interaction.
For pet owners, the research offers a useful reminder: not every animal experiences human interaction in the same way.
An animal's willingness to approach a hand does not necessarily mean it wants to be handled or tickled. Respecting its individual behaviour, allowing it to withdraw, and avoiding forced interactions are essential for responsible care.
Conclusion: One Size Does Not Fit All in Animal Play
The study by Sarah Dagher and her team reveals that social play is shaped by both species-specific characteristics and selective breeding.
Tame mice showed increased playful responses toward humans, including hand chasing and vocalisations, whereas golden hamsters displayed a stronger preference for interactions with their own species. Both animals also showed differences in vocal communication depending on their social partners.
These findings expand our understanding of animal play and raise new questions about how social behaviour evolves. They also demonstrate that the relationship between humans and animals is more complex than simple friendliness.
Ultimately, studying how different species play, communicate, and form social connections may help scientists uncover the biological foundations of social behaviour—and remind us that every animal has its own way of interacting with the world.
Reference: Sarah Dagher, Darcie DeAngelo, Ren Y. Sato, Hiroaki Norimoto, Tsuyoshi Koide, Shimpei Ishiyama, Comparative analysis of tickling and conspecific play in tame mice and golden hamsters, Behavioural Brain Research, Volume 496, 2026, 115849, ISSN 0166-4328, https://doi.org/10.1016/j.bbr.2025.115849. (https://www.sciencedirect.com/science/article/pii/S016643282500436X)
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