Since their introduction in the 1920s, jungle gyms and monkey bars have become common sights on playgrounds but also evoke concerns among worried guardians about the potential for injuries. Anthropologists commemorate a century of these playground staples by asserting that adventurous play serves a biological purpose inherited from our primate ancestors, allowing children to test and enhance their physical and mental skills in environments where risks of injury exist but can be mitigated.
As schools across the country resume their sessions, millions of kids in the United States will scramble up jungle gyms and dangle from monkey bars, which have been playground mainstays since their invention in the 1920s.
Over the years, however, these metal structures have also become emblematic of playground dangers for many apprehensive parents and officials who advocate for their removal from parks and schools to prevent sporadic bumps and fractures.
A group of Dartmouth anthropologists presents a different analysis as they mark a century since the patenting of jungle gyms and monkey bars. They argue that such iconic equipment, along with other forms of risky play, meet an essential biological need derived from both ape and early human behaviors, potentially vital for a child’s development.
In a paper published in the journal Evolution, Medicine, and Public Health, the researchers caution that a growing trend toward excessive safety on playgrounds might hinder children’s opportunities to independently explore and expand their physical and cognitive capabilities even in settings where injury is possible but preventable.
“It’s ironic that despite our children being physically safer now than ever, our anxiety about their safety has surged. We must evaluate the potential long-term advantages of allowing them to play in a way that carries some risk, so they can learn to tackle challenges independently and gain insights when things don’t go as planned,” says Zane Thayer, co-author of the study and an anthropology associate professor at Dartmouth.
“Research generally indicates that risky play helps children develop resilience and self-confidence, skills that are crucial throughout life,” she adds. “We highlight jungle gyms and monkey bars as simple avenues for kids to engage in thrilling and risky play.”
The researchers note that the anatomy, along with fossil injuries of early humans, suggests that young children actively participated in swinging, climbing, jumping, and various forms of adventurous play. The remains of a 3.3-million-year-old child known as Selam, a female Australopithecus afarensis, exhibit physical adaptations like shoulders, fingers, and toes suited for tree climbing and hanging, much like today’s apes. The 3.2-million-year-old skeleton of Lucy, an adult of the same species, shows healed injuries believed to be from falls up to 40 feet high.
“Fossil evidence suggests that early human juveniles spent as much time in trees as their adult counterparts,” states Luke Fannin, the lead author and a PhD candidate in the Ecology, Evolution, Environment, and Society program at the Guarini School of Graduate and Advanced Studies.
“If young ones are spending considerable time in trees, they need to build confidence, since falling can have serious, even fatal, consequences for larger primates,” he explains. “We observe modern nonhuman primates testing their abilities and assessing risks, which helps develop their climbing skills as adults.”
The Dartmouth researchers reference a 2014 study revealing that infant and young chimpanzees spend significantly more time climbing and swinging compared to adults—15% and 27%, respectively—which sharpens their dexterity, skills, and body awareness. Fannin notes that while modern humans may lack the climbing finesse of other primates, they are still capable climbers, with hunter-gatherers having been known to ascend trees up to 150 feet high for foraging.
“Historical and contemporary evidence suggests that children enhance their physical and experiential skills by exploring their limitations through play,” Fannin says. “Our bodily structure as children still facilitates climbing, running, and jumping, and we recover from minor injuries and falls more readily.”
“It’s uncommon to see such a strong connection between anthropology and our daily lives,” Fannin remarks. “People seldom consider our ancestry, but play serves as a link between our past and present.”
Nathaniel Dominy, the Charles Hansen Professor of Anthropology and co-author of the study, discusses how the inventor of jungle gyms and monkey bars, Sebastian “Ted” Hinton, acknowledged this link.
In one of his patent applications, Hinton claimed that children possess a “monkey instinct” to climb for fun and physical activity. He lived during a time when outdoor pursuits gained popularity in the early 20th century, culminating in the establishment of the National Park Service, the planning of the Appalachian Trail, and the creation of Scouting programs.
However, Dominy notes that Hinton perceived climbing as a remnant of our primate lineage even before this connection was scientifically proven. The discovery of the Taung Child, an 2.8-million-year-old Australopithecus africanus fossil that established a crucial link between contemporary humans and their ape-like ancestors, was reported three years later, in 1925.
“Hinton was at the forefront of a cultural movement that recognized nature as vital for fitness but largely concentrated on bipedal movement. He characterized climbing as essential for childhood growth and development even before we had concrete evidence to back it up,” Dominy explains.
“A century later, jungle gyms and monkey bars are still central to discussions about childhood play. Yet the insights from anthropology are often missing from this dialogue, which is what we aimed to change,” Dominy states. “Our research illustrates how evolutionary theories can enhance both research and practices in public health.”
Data on hospital admissions indicate that jungle gyms and monkey bars are linked to more childhood fractures and emergency visits compared to other playground equipment. However, the likelihood of playground injuries remains quite low.
The Dartmouth team refers to a 2003 study estimating the risk of playground injuries to be no higher than 0.59 per 100,000, significantly lower than injuries from organized sports or even physical education. Another analysis revealed that 95% of children with playground injuries were treated and discharged between 2001 and 2013.
“Free play enables children to adapt their activities according to their physical capabilities and self-assurance,” Fannin explains. “The norms surrounding free play evolve over extended periods, contrasting with the more immediate rules and expectations set by adults in organized sports, where injuries often stem from the social context involved.”
Despite this, jungle gyms and monkey bars continue to be scrutinized in efforts to enhance playground safety, the researchers highlight. For instance, New York City removed these structures from many of its 862 public playgrounds during the 1980s and 1990s. Seven states have enacted the U.S. Consumer Product Safety Commission’s safety guidelines for monkey bars, but enforcing these regulations is challenging, leading many municipalities to eliminate the equipment altogether.
Thayer expresses, “We understand the concerns of parents, educators, and policymakers regarding children’s safety. Nonetheless, we must also weigh the long-term advantages of engaging in such types of play. Risky play, where children push their boundaries, is a normal aspect of development, just as it was for our ancestors.”
