A rural official in Japan shows off a mechanical Monster Wolf, invented to frighten away wildlife.
Credit: © Toru Yamanaka, Getty Images

The Japanese motion picture Gojira (1954) introduced one of the most recognizable monsters in popular culture, often called by its American name, Godzilla. In the film, the giant, dinosaurlike monster goes on a destructive rampage through Tokyo. Now, Japan has a new monster—but, unlike Godzilla, this monster protects the country’s people.

This fall, officials in the city of Takikawa—on Japan’s northern island of Hokkaido—installed two mechanical wolves near a residential neighborhood in which bears had injured or killed people in recent months. Wild bears in search of food had been entering areas on the edge of Takikawa, walking through yards and rummaging through trash. Rural areas often serve as barriers between the wilderness and urban areas. But, as rural populations shrink, so too does the barrier between wilderness and populated areas.

Each Monster Wolf, as the machines are called, looks a lot like a normal wolf, if you ignore the metal legs and flashing red eyes. A Monster Wolf is 4 feet (1.2 meters) long and just under 3 feet (0.9 meter) tall. Along with its fake fur and bared fangs, the Monster Wolf shares perhaps the wolf’s most distinctive feature, an eerie howl. The Monster Wolf’s head has motion detectors that are triggered when intruders approach. The wolf then produces howling, screeching sounds. Other frightening noises the robot can imitate include a dog’s bark, a hunter’s voice, and gunshots.

The mechanical wolves in Takikawa are not the country’s first. Since the Monster Wolf was created in 2016, more than 70 of them have been installed in communities across Japan. The creations have previously scared off such animals as deer and monkeys, which have been filmed leaping away from the mechanical nightmares. Since the wolves showed up in Takikawa, there have been no bear sightings.

June 5, 2012

For a tiny mosquito, being hit by a fat raindrop should be roughly equivalent to a person being slammed by a bus. However, mosquitoes are struck by raindrops all the time–and they usually survive. The secret of their success? They ride the raindrop, says mechanical engineer David Hu of the Georgia Institute of Technology in Atlanta. Why is this important? The mosquito’s low mass may explain how they are able to survive in rainy, humid climates. And it reveals why a rainstorm offers little or no protection against the pesky bloodsuckers. Engineers may also find the mosquito’s survival technique useful for designing tiny robotic flying machines that can operate under harsh weather conditions.

A female mosquito feeds from a person using her needlelike mouth parts. Her abdomen has become swollen with red blood. A female must drink blood to nourish her eggs. (© Dmitry Knorre, Dreamstime)

For their study, Hu and his team put mosquitoes in cages that vibrated so the insects wouldn’t be able to land. Then they bombarded the bugs with rainstorm-like waterdrops that were 50 times as heavy as the mosquitoes and came at them at a speed of 30 feet (9 meters) per second. High-speed videos of the blitz revealed that the flying mosquitoes simply stuck to the droplets. In the process, they absorbed only 10 percent of the force of the droplet. The maneuver is an insect version of t’ai chi ch’uan, Hu said, in which one minimizes the force of an attacking opponent by not resisting. In contrast, droplets falling on mosquitoes sitting on a twig crushed the bugs with a force equal to 10,000 times the mosquito’s weight.

The hitchhiking insects tumbled for a distance of up to about 20 times their body length before flying off. The bugs’ water-resistant hairs likely aid in their escape. But the scientists found that low-flying mosquitoes ran the risk of running out of escape room, with the raindrops becoming watery coffins.