These incredibly furry monkeys are diurnal, active during daylight hours. And they are mostly terrestrial, traveling and foraging on the ground. But they venture into the trees when they feel like it. Apart from choosing an overnight sleeping site, for some groups, their arboreal exploits appear to be for fun. Japanese macaques are superb jumpers, and their leaps have been likened to that of the obstacle-leaping sport of parkour. Though they don’t typically hang by their arms from tree limbs, as some monkeys do, Japanese macaques could win a medal for swimming; they are capable of swimming more than 0.3 miles (0.5 kilometers).

Females reportedly spend more time in trees than males, while males spend more time on the ground than females. The species is primarily quadrupedal (using all four limbs to travel), but Japanese macaques sometimes walk bipedally (upright on their hind legs)—particularly when carrying something, like a fish, in both hands. Their opposable thumbs not only allow them to securely grab onto branches as they advance from one tree to the next but also assist in grabbing and holding objects.

Their decision to choose trees as overnight sleeping sites or to sleep on the ground is largely determined by the presence or absence of predators. Natural predators include mountain hawk eagles (Nisaetus nipalensis), raccoon dogs (Nyctereutes viverrinus), and feral dogs. The macaques had also once been preyed upon by the Japanese wolf (Canis lupus hodophilax), but this species has been extinct for more than 100 years—or has it? (Some enthusiasts believe they have evidence that these apex predators, so-called “ghost wolves,” still roam the Japanese mountains.)

Those Japanese macaques who share habitat with predators are more likely to sleep in trees, either individually or, when the temperature drops, huddled together for warmth. They choose deciduous trees to prevent accumulated snow from falling on top of them.

When no predators are present, as is the case on the small, mountainous island of Kinkazan (also known as Kinkasan) at the tip of the Oshika Peninsula in Miyagi Prefecture, these macaques typically choose to sleep on the ground. Seasonal and environmental conditions are additional determining factors. During the spring and summer, the macaques sleep at lower altitudes in grasslands where food is abundant. Autumn finds the macaques in sleeping sites at a range of altitudes, from sea level to 984 feet (300 meters), but they avoid high-altitude forests dominated by Japanese beech trees where strong winds are prevalent. During winter months, the macaques show a preference for valleys with fallen trees and rocky ridges that offer a greater degree of shelter from the wind and cold, allowing the monkeys to conserve energy and maintain a core body temperature independent of environmental temperature. (This natural phenomenon is known as thermoregulation).

Of course, Japanese macaques are renowned for another strategy that they use to keep warm in their frigid, snowy habitat: Those residing in Honshu’s Japanese Alps, commonly referred to by their nickname of snow monkey, routinely soak themselves in geothermal springs heated by nearby volcanoes. Poofy, fluffy heads and torsos bob and splash in the steamy water amidst a wintry landscape. Bath time is a family affair, and young offspring stay close to their mothers.

But these “hot tub” visits are learned behavior. Back in the early 1960s, in the course of conducting a field study on macaque behavior, wildlife researchers tossed a handful of soybeans into a hot spring. A Japanese macaque whom the researchers named “Mukubili” waded into the hot water to retrieve this free handout. And she stayed there. The 109-degree Fahrenheit (43 degrees Celsius) water temperature warmed her body, and her children and other young monkeys joined her. Eventually, over a period of many months, all troop members were soaking in the hot spring to keep warm. Fast forward to today: these snow monkeys are iconic for their hot spring soaks.

Anthropologists had once believed that only humans passed on learned behaviors to other individuals and across generations, a process called “cultural transmission.” Snow monkeys demolished this hypothesis.

The practice of soaking in hot springs is not the only example of cultural transmission with Japanese macaques. Their practice of washing foods prior to eating is another. Researchers conducting a field study in the 1950s observed a female macaque, dubbed “Imo,” rinse the sand off a sweet potato she was about to eat by dipping the tuber in a freshwater stream. Other members of her troop followed her lead, and this behavior has since been passed down through generations.

Over time, the macaques began rinsing potatoes in salt water. This modification led researchers to add their own culinary, if not scientific, spin on the practice: By rinsing the potatoes in salt water, rather than fresh, the macaques intentionally season their food for an enhanced epicurean experience. Aquatic insects provide the macaques with snacks and bamboo leaves cleanse their palate.

One of the most remarkable evolved foraging behaviors is seen in those individuals living in the Japanese Alps of Honshu, within the remote mountainous valley of Kamikōchi, western Nagano Prefecture. These macaques have taught themselves to fish! Researchers believe the behavior is unique to this population, evolved to obtain important animal protein during winter months when other foods are unavailable. So how does a snow monkey catch a fish? With its hands, of course. By overturning rocks where fish are hiding, chasing a fish into shallow water, grabbing the fish with both hands and then chomping down on the fish with its mouth.

Unsurprisingly, scientists consider macaques to possess an enhanced general intelligence when compared with other mammals. These primates’ innovative survival behaviors offer proof.