Primates in Japan de- stress by relaxing in hot springs
The snow monkeys of Japan are famous, as monkeys go. This troop of Japanese macaques lives in the north, near Nagano, the mountainous, snowy site of the 1998 Winter Olympics.
Others of their species live even farther north, farther than any other nonhuman primate, so they are able to adapt to winter weather. But the source of this troop’s fame is an adaptation that only they exhibit: soaking in hot spring bathing pools.
Their habitat is full of natural hot springs that tend to be more than 140 degrees Fahrenheit, a temperature that apparently is uncomfortable for the monkeys.
It wasn’t until 1963 that a young female macaque was first observed bathing in a pool built by a hotel, with the water cooled to a temperature comfortable enough for humans and monkeys.
At first, a few monkeys joining human visitors was a curiosity, but eventually they became a nuisance and health hazard, and a park was built with hot spring pools at 104 degrees and for monkeys only.
The monkeys have been a longtime tourist attraction and favorite of photographers, and it looked like they were trying to stay warm. Only recently have scientists investigated this behavior by measuring levels of stress hormones and observing the effects of social structure.
Rafaela S.C. Takeshita and her colleagues at Kyoto University collected and tested the monkeys’ feces for levels of glucocorticoids, which increase with stress. The cold is known to cause levels of these hormones to go up. They published their results in the journal Primates.
As expected, during the periods when the monkeys were bathing, stress levels were down. Another indication of the value of bathing to the macaques was that the higherranking females spent more time in the pools.
Takeshita said the males are usually on the periphery of the troop at this time of year and did not spend much time bathing, so she studied the females.
She also said she was inspired by the monkeys, in a nonscientific way.
“I confess that during my research, many times after, I jumped into one of the hot springs pools” — the ones for humans, that is. Researchers trace migration through ancient finger bone
An ancient human finger bone found in Saudi Arabia provides a new clue about when and how our species migrated out of Africa.
Researchers say it shows hunter-gatherers had reached that area by 85,000 years ago. Previously discovered human fossils show an earlier human presence in Israel and possibly China.
Scientists believe early people left Africa more than once after evolving there at least 300,000 years ago.
The bone, from an adult and most likely a middle finger, was found in 2016, about 340 miles southeast of the Sinai Peninsula. Michael Petraglia, a researcher in Germany, says the ancient people probably left Africa through the peninsula.
Don’t get behind wheel after upcoming ‘4/20’ parties
April 20 has become known as a day to celebrate the pleasures of marijuana consumption with parties that traditionally begin at 4:20 p.m.
But a study in JAMA Internal Medicine has found that the high spirits come with a price: a significant increase in fatal car wrecks after the “4/20” parties.
Researchers used 25 years of data on fatal car crashes in the United States. They compared the number of fatal crashes between 4:20 p.m. and midnight on April 20 each year with those during the same hours one week before and one week after that date.
Before 4:20 p.m. there was no difference between the number of fatalities on April 20 and the number on the nearby dates. But from 4:20 p.m. to midnight, there was a 12 percent increased risk of a fatal car crash on April 20. The increased risk was particularly large in drivers 20 and younger.