In humans, play is considered to be a sign of happiness and good health, and has long been recognized as an important component of child development. Play continues into adulthood, where it may take the form of board games and sport. Playing is also common among nonhuman animals: We have all seen dogs play fighting, cats chasing laser toys, or rabbits jumping in the air and twisting their body and head in comical ways.
In humans as in other animals, playing not only is enjoyable, but also helps with the development of motor skills, management of stress, strengthening of social bonds, and engagement of creativity and problem solving.
The idea that animal play is important and worthwhile is gaining traction within the biomedical research community. Indeed, the PRIM&R’s 2019 IACUC Conference (the acronyms stand for “Public Responsibility in Medicine and Research” and “Institutional Animal Care and Use Committee”)—an annual gathering that brings together approximately 600 professionals from state and federal government, industry, and academia—included for the first time this year a session on the importance of play for animals in research.
Panelists Melanie Graham, Debra Hickman, and AWI’s Joanna Makowska discussed how allowing laboratory animals to play is first and foremost “fun” for the animals: Their daily routine is broken up with voluntary physical activity and exploration. Moreover, animals will engage in play only when they are feeling well; therefore, play is also a useful indicator of animal welfare, because individuals who are sick or stressed are less likely to engage in play.
Allowing laboratory animals to play can also help improve data quality. For example, play strengthens social bonds, thus helping to prevent pair or group breakdown in captive environments. This, in turn, prevents confounding results related to potential injury from fighting, chronic stress from living in a tense environment, or single housing of social species. The physical activity involved in social and object play can also prevent unintended divergence from the target clinical population—in other words, the increased activity can help make the animals metabolically more “normal.”
Play within laboratories can be encouraged in various ways. Playful interactions between caretakers and animals build trust and facilitate cooperation with routine medical interventions. In rats, a playful handling technique referred to as “rat tickling” improves the welfare of rats as well as the relationship with the human tickler.
Animals should also be encouraged to play with each other and interact with toys. This may be difficult to accomplish for animals housed in small, standard cages. One solution is to give these standard-housed animals regular access to a “playpen” consisting of a large area furnished with interesting objects and toys in which the animals can run around, explore, and play with each other. Some facilities have built permanent communal playrooms behind or above primate cages that animals have access to when a hutch is opened by a caretaker. For rodents, cages designed for larger species, such as ferrets or rabbits, can be furnished with rat-friendly toys and placed within the animal-housing room.
In addition to their importance for animal welfare and research results, play sessions are likely to be the highlight of the day—not only for the animals, but also for the caretakers who get to watch them have a good time.