Punishing headbutts damage the brains of musk oxen. That observation, made for the first time and reported May 17 in Acta Neuropathologica, suggests that a life full of bell-ringing clashes is not without consequences, even in animals built to bash.
Although a musk ox looks like a dirty dust mop on four tiny hooves, it’s formidable. When charging, it can reach speeds up to 60 kilometers an hour before ramming its head directly into an oncoming head. People expected that musk oxen brains could withstand these merciless forces largely unscathed, “that they were magically perfect,” says Nicole Ackermans of the Icahn School of Medicine at Mount Sinai in New York City. “No one actually checked.” In fact, the brains of three wild musk oxen (two females and one male) showed signs of extensive damage, Ackermans and her colleagues found. The damage was similar to what’s seen in people with chronic traumatic encephalopathy, a disorder known to be caused by repetitive head hits (SN: 12/13/17). In the musk ox brains, a form of a protein called tau had accumulated in patterns that suggested brain bashing was to blame.
In an unexpected twist, the brains of the females, who hit heads less frequently than males, were worse off than the male’s. The male body, with its heavier skull, stronger neck muscles and forehead fat pads, may cushion the blows to the brain, the researchers suspect.
The results may highlight an evolutionary balancing act; the animals can endure just enough brain damage to allow them to survive and procreate. High-level brainwork may not matter much, Ackermans says. “Their day-to-day life is not super complicated.”
Six years ago, tour guide Brenden Miles was traveling down the Kinabatangan River in the Malaysian part of Borneo, when he spotted an odd-looking primate he had never seen before. He snapped a few pictures of the strange monkey and, on reaching home, checked his images.
“At first, I thought it could be a morph of the silvered leaf monkey,” meaning a member of the species with rare color variation, Miles says. But then he noticed other little details. “Its nose was long like that of a proboscis monkey, and its tail was thicker than that of a silvered leaf [monkey],” he says. He posted a picture of the animal on Facebook and forgot all about it.
Now, an analysis of that photo and others suggests that the “mystery monkey” is a hybrid of two distantly related primate species that share the same fragmented habitat. The putative offspring was produced when a male proboscis monkey (Nasalis larvatus) mated with a female silvered leaf monkey (Trachypithecus cristatus), researchers suggest April 26 in the International Journal of Primatology. And that conclusion has the scientists worried about the creature’s parent species.
Hybridization between closely related organisms has been observed in captivity and occasionally in the wild (SN: 7/23/21). “But hybridization across genera, that’s very rare,” says conservation practitioner Ramesh Boonratana, the regional vice-chair for Southeast Asia for the International Union for Conservation of Nature’s primate specialist group.
Severe habitat loss, fragmentation and degradation caused by expanding palm oil plantations along the Kinabatangan River could explain how the possible hybrid came to be, says primatologist Nadine Ruppert.
“Different species — even from the same genus — when they share a habitat, they may interact with each other, but they may usually not mate. This kind of cross-genera hybridization happens only when there is some ecological pressure,” says Ruppert, of the Universiti Sains Malaysia in Penang Island.
The state of Sabah, where Kinabatangan River is located, lost about 40 percent of its forest cover from 1973 to 2010, with logging and palm oil plantations being the main drivers of deforestation, a study in 2014 found. “In certain areas, both [monkey] species are confined to small forest fragments along the river,” Ruppert says. This leads to competition for food, mates and other resources. “The animals cannot disperse and, in this case, the male of the larger species — the proboscis monkey — can easily displace the male silvered leaf monkey.”
Since 2016, there have been some more documented sightings of the mystery monkey, though these have been sporadic. The infrequent sightings and the COVID-19 pandemic has, for now, prevented researchers from gathering fecal samples for genetic analysis to reveal the monkey’s identity. Instead, Ruppert and colleagues compared images of the possible hybrid with those of the parent species, both visually as well as by using limb ratios. “If the individual was from one of the two parent species, all its measurements would be similar to that of one species,” Ruppert says. “But that is not the case with this animal.”
A photograph of a male proboscis monkey mating with a female silvered leaf monkey, along with anecdotes from boat operators and tour guides about a single male proboscis monkey hanging around a troop of female silvered leaf monkeys, has added further weight to the researchers’ conclusion.
The mystery monkey is generating a lot of excitement in the area, but Ruppert is concerned for the welfare of both proposed parent species. The International Union for Conservation of Nature classifies proboscis monkeys as endangered and silvered leaf monkeys as vulnerable. “The hybrid is gorgeous, but we don’t want to see more of them,” Ruppert says. “Both species should have a large enough habitat, dispersal opportunities and enough food to conduct their natural behaviors in the long term.”
Increasing habitat loss or fragmentation in Borneo and elsewhere as a result of changing land uses or climate change could lead to more instances of mating — or at least, attempts at mating — between species or even genera, Boonratana says.
The mystery monkey was last photographed in September of 2020 with swollen breasts and holding a baby, suggesting that the animal is a fertile female. That’s another surprising development, the researchers say, because most hybrids tend to be sterile.
One million deaths. That is now roughly the toll of COVID-19 in the United States. And that official milestone is almost certainly an undercount. The World Health Organization’s data suggest that this country hit a million deaths early in the year.
Whatever the precise dates and numbers, the crisis is enormous. The disease has taken the lives of more than 6 million people worldwide. Yet our minds cannot grasp such large numbers. Instead, as we go further out on a mental number line, our intuitive understanding of quantities, or number sense, gets fuzzier. Numbers simply start to feel big. Consequently, people’s emotions do not grow stronger as crises escalate. “The more who die, the less we care,” psychologists Paul Slovic and Daniel Västfjäll wrote in 2014. But even as our brains struggle to grasp big numbers, the modern world is awash in such figures. Demographic information, funding for infrastructure and schools, taxes and national deficits are all calculated in the millions, billions and even trillions. So, too, are the human and financial losses from global crises, including the pandemic, war, famines and climate change. We clearly have a need to conceptualize big numbers. Unfortunately, the slow drumbeat of evolution means our brains have yet to catch up with the times.
Our brains think 5 or 6 is big. Numbers start to feel big surprisingly fast, says educational neuroscientist Lindsey Hasak of Stanford University. “The brain seems to consider anything larger than five a large number.”
Other scientists peg that value at four. Regardless of the precise pivot from small to big, researchers agree that humans, along with fish, birds, nonhuman primates and other species, do remarkably well at identifying really, really small quantities. That’s because there’s no counting involved. Instead, we and other species quickly recognize these minute quantities through a process called “subitizing” — that is, we look and we immediately see how many.
“You see one apple, you see three apples, you would never mistake that. Many species can do this,” says cognitive scientist Rafael Núñez of the University of California, San Diego.
When the numbers exceed subitizing range — about four or five for humans in most cultures — species across the biological spectrum can still compare approximate quantities, says cognitive scientist Tyler Marghetis of the University of California, Merced.
Imagine a hungry fish eyeing two clumps of similarly sized algae. Because both of those options will make “awesome feasts,” Marghetis says, the fish doesn’t need to waste limited cognitive resources to differentiate between them. But now imagine that one clump contains 900 leaves and the other 1,200 leaves. “It would make evolutionary sense for the fish to try to make that approximate comparison,” Marghetis says. Scientists call this fuzzy quantification ability an “approximate number sense.” Having the wherewithal to estimate and compare quantities gives animals a survival edge beyond just finding food, researchers wrote in a 2021 review in the Journal of Experimental Biology. For example, when fish find themselves in unfamiliar environments, they consistently join the larger of two schools of fish.
The approximate number system falls short, however, when the quantities being compared are relatively similar, relatively large or both. Comparing two piles, one with five coins and the other with nine coins, is easy. But scale those piles up to 900,005 coins and 900,009 coins, and the task becomes impossible. The same goes for when the U.S. death toll from COVID-19 goes from 999,995 to 999,999.
We can improve our number sense — to a point. The bridge between fuzzy approximation and precision math appears to be language, Núñez says.
Because the ability to approximate numbers is universal, every known language has words and phrases to describe inexact quantities, such as a lot, a little and a gazillion. “For example, if a boy is said to have a ‘few’ oranges and a girl ‘many’ oranges, a safe inference — without the need of exact calculations — is that the girl has more oranges than the boy,” Núñez writes in the June 1, 2017 Trends in Cognitive Science.
And most cultures have symbols or words for values in the subitizing range, but not necessarily beyond that point, Núñez says. For instance, across 193 languages in hunting and gathering communities, just 8 percent of Australian languages and 39 percent of African languages have symbols or words beyond five, researchers reported in the 2012 Linguistic Typology. The origin of counting beyond subitizing range, and the complex math that follows, such as algebra and calculus, remains unclear. Núñez and others suspect that cultural practices and preoccupations, such as keeping track of agricultural products and raw materials for trade, gave rise to more complex numerical abilities. As math abilities developed, people became adept at conceptualizing numbers up to 1,000 due to lived experience, says cognitive scientist David Landy. Those experiences could include getting older, traveling long distances or counting large quantities of money.
Regular experiences, however, rarely hit the really big number range, says Landy, a senior data scientist at Netflix in San Francisco. Most people, he says, “get no experience like that for a million.”
Numbers that exceed our experience perplex us. When big numbers exceed our lived experiences, or move into the abstract, our minds struggle to cope. For instance, with number sense and language so deeply intertwined, those seemingly benign commas in big numbers and linguistic transitions from thousands to millions or millions to billions, can trip us up in surprising ways.
When Landy and his team ask participants, often undergraduates or adults recruited online, to place numbers along a number line, they find that people are very accurate at placing numbers between 1 and 1,000. They also perform well from 1 million to 900 million. But when they change the number line endpoints to, say, 1,000 and 1 billion, people struggle at the 1 million point, Landy and colleagues reported in the March 2017 Cognitive Science.
“Half the people are putting 1 million closer to 500 million than 1,000,” Landy says. “They just don’t know how big a million is.” Landy believes that as people transition from their lived experiences in the thousands to the more abstract world of 1 million, they reset their mental number lines. In other words, 1 million feels akin to one, 2 million to two and so on.
Changing our notations might prevent that reset, Landy says. “You might be better off writing ‘a thousand thousand’ than ‘1 million’ because that’s easier to compare to 900,000.” The British used to do this with what people in the U.S. now call a trillion, which they called a million million.
Without comprehension, extreme numbers foster apathy. Our inability to grasp big numbers means that stories featuring a single victim, often a child, are more likely to grab our attention than a massive crisis — a phenomenon known as the identifiable victim effect.
For instance, on September 2, 2015, Aylan Kurdi, a 2-year-old refugee of the Syrian Civil War, was on a boat with his family crossing the Mediterranean Sea. Conservative estimates at the time put the war’s death toll at around 250,000 people. Kurdi’s family was trying to escape, but when their overcrowded boat capsized, the boy drowned, along with his brother and mother. The next day a picture of the infant lying dead on a Turkish beach hit the front pages of newspapers around the world.
No death up until that point had elicited public outcry. That photograph of a single innocent victim, however, proved a catalyst for action. Charitable contributions to the Swedish Red Cross, which had created a fund for Syrian refugees in August 2015, skyrocketed. In the week leading up to the photo’s appearance, daily donations averaged 30,000 Swedish krona, or roughly $3,000 today; in the week after the photo appeared, daily donations averaged 2 million Swedish krona, or roughly $198,500. Paul Slovic, of the University of Oregon, Eugene, Daniel Västfjäll, of Linköping University, Sweden, and colleagues reported those results in 2017 in Proceedings of the National Academy of Sciences. Earlier research shows that charitable giving, essentially a proxy for compassion, decreases even when the number of victims goes from one to two. The flip side, however, is that psychologists and others can use humans’ tendency to latch onto iconic victims to reframe large tragedies, says Deborah Small, a psychologist at the University of Pennsylvania.
Some research suggests that this power of one need not focus on a single individual. For instance, when people were asked to make hypothetical donations to save 200,000 birds or a flock of 200,000 birds, people gave more money to the flock than the individual birds, researchers reported in the 2011 E-European Advances in Consumer Research.
Framing the current tragedy in terms of a single unit likewise makes sense, Västfjäll says. Many people react differently, he says, to hearing ‘1 million U.S. citizens dead of COVID’ vs. ‘1 million people, roughly the equivalent of the entire city of San José, Calif., have died from COVID.’
Milestones do still matter, even if we can’t feel them. Kurdi’s photo sparked an outpouring of empathy. But six weeks after it was published, donations had dropped to prephoto levels — what Västfjäll calls “the half-life of empathy.”
That fade to apathy over time exemplifies a phenomenon known as hedonic adaptation, or humans’ ability to eventually adjust to any situation, no matter how dire. We see this adaptation with the pandemic, Small says. A virus that seemed terrifying in March 2020 now exists in the background. In the United States, masks have come off and people are again going out to dinner and attending large social events (SN: 5/17/22).
One of the things that can penetrate this apathy, however, is humans’ tendency to latch onto milestones — like 1 million dead from COVID-19, Landy says. “We have lots of experience with small quantities carrying emotional impact. They are meaningful in our lives. But in order to think about big numbers, we have to go to a more milestone frame of mind.” That’s because our minds have not caught up to this moment in time where big numbers are everywhere.
And even if we cannot feel that 1 million milestone, or mourn the more than 6 million dead worldwide, the fact that we even have the language for numbers beyond just 4 or 5 is a feat of human imagination, Marghetis says. “Maybe we are not having an emotional response to [that number], but at least we can call it out. That’s an amazing power that language gives us.”
A speck of gold dancing to a pipe organ’s tune has helped solve a long-standing mystery: why certain wind instruments violate a mathematical formula that should describe their sound.
In 1860, physicist Hermann von Helmholtz — famous for his law of the conservation of energy — devised an equation relating the wavelength of a pipe’s fundamental tone (the lowest frequency at which it resonates) to pipe length (SN: 3/31/28). Generally, the longer a pipe is, the lower its fundamental tone will be.
But the equation doesn’t work in practice. A pipe’s fundamental tone always sounds lower than the pipe’s length suggests it should according to Helmholtz’s formula. Fixing this problem requires adding an “end correction” to the equation. In the case of open-ended pipes such as flutes and those of organs, the end correction is 0.6 times the radius of the pipe. Why this was, nobody could figure out.
A break in the case came in 2010. Instrument builder and restorer Bernhardt Edskes of Wohlen, Switzerland was tuning an organ when he spotted a piece of gold that had come loose from a pipe’s gilded lip. Air pumping through the pipe should have carried away the gold. Instead, it seemed to be trapped in a vortex just above the pipe’s upper rim.
Edskes told his friend, physicist Leo van Hemmen of the Technical University of Munich, about the observation. Together with colleagues from Munich and Wageningen University in the Netherlands, they studied how air moves through playing organ pipes using cigarette smoke.
When an organ pipe sounds, a vortex indeed forms over the pipe’s rim, the team reported March 14 in Chicago at a meeting of the American Physical Society. What’s more, this vortex is capped by a hemisphere of resonating air. This vibrating air cap, van Hemmen says, is the long-sought explanation for the “end correction.” The cap effectively lengthens the organ pipe by the exact amount that must be tacked on to Helmholtz’s formula to explain the pipe’s fundamental tone.
