5,000 years ago riding left traces on the legs and butts of the earliest horsepeople; Whales use ‘vocal fry’ to echolocate at depth; Fossils suggest that if equatorial oceans get too warm, plankton may desert; Scientists have mapped the most complex animal brain yet - and it's the size of a grain of salt; A new book explores the unique biology and uncertain fate of Australia’s iconic koala.

Earliest horsepeople, whales use ‘vocal fry’, plankton might migrate poleward, mapping a fruit fly brain and understanding the cuddly, cute and really strange koala

CBC Radio's Quirks and Quarks covers the quirks of the expanding universe to the quarks within a single atom... and everything in between.

Science

Earth Sciences

Chimpanzees are being forced to eat bat feces, and the viruses in it Researchers in Uganda have noticed a new behaviour in the wild chimps they study. The apes are browsing on bat guano, apparently to access the nutrients it contains, as their normal source for these nutrients has been destroyed by humans. Since bats are carriers of a range of diseases, from ebola to coronaviruses, this may be a new way these diseases could spread. The study was published in Communications Biology. Dr Tony Goldberg, a professor of epidemiology at the school of veterinary medicine at the University of Wisconsin-Madison, was part of the team. 
 Controversial methods are working to buy Canada’s caribou some time Woodland caribou have been in steady decline for decades, as logging, oil and gas exploration and other disturbances compromise their western mountain habitat. Steady progress has been made to restore habitat in order to save these caribou, but since these forests will take half a century to regrow, conservationists are trying a variety of interim actions to buy the caribou some time. A new study led by Clayton Lamb from the University of British Columbia Okanagan found that these methods, including direct feeding, maternal penning, and, controversially, culling predatory wolves, have helped caribou recover to some extent, but restoration of their habitat will be necessary for full recovery. The research was published in the journal Ecological Applications. 
 Giant ancient Pacific salmon had tusks sticking out of its face Millions of years ago, enormous three metre-long salmon inhabited the seas of the Pacific coast. Named Oncorhynchus rastrosus, this ancient giant was first described in the 1970s as having long front fangs, which led to it being known colloquially as a “saber-toothed salmon.” But a new study published in PLOS ONE sets the record straight: the teeth actually protruded out to the sides from the fish’s upper jaw, as tusks do. Lead study author and Philadelphia College of Osteopathic Medicine professor Kerin Claeson says despite their menacing look, the salmon did not hunt with these tusks, since these strange fish were filter feeders. 
 The Gulf oil spill may have had ecological impacts we haven’t seen yet Fourteen years ago an explosion destroyed the Deepwater Horizon oil rig and kicked off the largest oil spill in history. While commercial fisheries have largely recovered from the disaster, there are signs that rarer and more vulnerable species might have been devastated. Prosanta Chakrabarty from Louisiana State University surveyed deep sea fish catalogued in museum collections around the world and found that out of 78 endemic species found only in the Gulf, 29 of them haven’t been spotted in the years since the spill. The research was published in the Biodiversity Data Journal. 
 Primordial black holes may be the solution the problem of missing dark matter The hunt for exotic black holes that Stephen Hawking first predicted back in the 1970s is now well underway. Primordial black holes behave just like any other black hole, but they would have  formed in the early universe and could  be any size. Many scientists are particularly interested in the primordial black holes that are the size of an atom and have the mass of an asteroid because they suspect they could be the answer for the missing dark matter in our universe.  


Tiny black holes that could smash through our planet, and more…

The climate is changing. So are we. On What On Earth, you’ll explore a world of solutions with host Laura Lynch and our team of journalists. In 1970, 20 million people showed up to fight for the environment on the first Earth Day. More than five decades later, is it time for this much tamer global event to return to its radical roots?  
 OG organizer Denis Hayes recounts how – amidst other counterculture movements at the time – his team persuaded roughly one in ten Americans to take to the streets. As he approaches 80, Denis offers his singular piece of advice to the next generation of climate leaders. Then, environmental warriors Maria Blancas and Axcelle Campana share ideas on what a reinspired Earth Day could look like – including making it a public holiday. 
 More episodes of What On Earth are available at: https://link.chtbl.com/5zF03qcm 
 We love to hear from our listeners and regularly feature them on the show. Have a question or idea? Email Earth@cbc.ca

Bonus: What On Earth's Earth Day special

This researcher wants a new particle accelerator to use before she’s dead Physicists exploring the nature of reality need ever more capable particle colliders, so they’re exploring a successor to the Large Hadron Collider in Europe. But that new machine is at least decades away. Tova Holmes, an assistant professor at the University of Tennessee, Knoxville, is one of the physicists calling for a different kind of collider that can come online before the end of her career – or her life. This device would use a particle not typically used in particle accelerators: the muon. 
 Is venting the best way to deal with anger? The scientist says chill out. It turns out that acting out your anger might not be the best way to get rid of it. Sophie Kjaervik, a researcher at Virginia Commonwealth University in Richmond, Va., analyzed 154 studies of the different ways to deal with anger. Her results, published in the journal Clinical Psychology Review, suggest that techniques that reduce your heart rate and calm your mind are more effective than blowing off steam. 
 High intensity wildfires may release toxic forms of metals Wildfire smoke might be more dangerous than you think. A recent study in the journal Nature Communications found that when wildfires pass over soils or rocks rich in a normally harmless metal called chromium, it is transformed into a toxic form. The hotter and more intense the wildfire is, the more of this metal becomes toxic. Scott Fendorf, an Earth system science professor at Stanford University, said this study shows we should factor in the type of geology wildfires pass over to provide more targeted air quality warnings about smoke risks.  
 AI might help solve the problem of runaway conspiracy theories Conspiracy theories seem to have multiplied in the internet era and so far, we haven’t had much luck in debunking these beliefs. The preliminary findings of a new study on PsyArXiv, a site for psychology studies that have yet to be peer-reviewed, suggests that artificial intelligence may have more success. Thomas Costello, a postdoctoral psychology researcher at MIT was the lead author on this study, and said their findings can provide a window into how to better debunk conspiracy beliefs.  
 An Indigenous ecologist on why we need to stop and listen to save the planet Earth day is April 22. And Earth is not in great shape to celebrate the day. Overheated, overpopulated, overexploited – we’re not being particularly careful with our planet. We talk to Indigenous ecologist Jennifer Grenz, of the University of British Columbia, about her new book, which is part memoir, part prescription for the medicine our planet needs – a compound of science and traditional wisdom. Her book is Medicine Wheel for the Planet: A journey toward personal and ecological healing.

Why this Indigenous researcher thinks we can do science differently, and more…

Old canned salmon provides a record of parasite infection To study marine ecosystems from the past, scientists picked through canned salmon dating back more than four decades to measure levels of parasites in the fish. Natalie Mastick, a postdoctoral researcher in marine ecology at Yale University, said she found the parasite load in two species of salmon increased in their samples between 1979 - 2021. She says this suggests their ecosystems provided more of the hosts the parasites needed, including marine mammals, which could reflect an increasingly healthy ecosystem. Their study is in the journal Ecology and Evolution.  
 Mars has more influence on Earth than non-astrologers might have thought Mars is, on average, about 225 million km from Earth, which would suggest that it has little impact on our planet. Which is true, but as they say a little goes a long way. In a recent study in Nature Communications, researchers studying the history of deep ocean currents found a surprising 2.4-million-year cycle where giant whirlpools form on the ocean floor, linked to cycles in the interactions of Mars and Earth orbiting the Sun. The team, including geophysicist Dietmar Müller from the University of Sydney, say this may act as a backup system to mix the oceans as the Earth warms. 
 Medieval English silver pennies travelled a long way Starting in the middle of the 7th century, economic development in medieval England was spurred by the increasing use of handy silver coins that greased the wheels of trade. To date, 7000 of these silver coins have been found that date to the period between the years 660 and 750 AD, but the source of the silver has been mysterious. Using modern technology, researchers from the University of Cambridge, including historian Rory Naismith,  have traced the silver right across the continent to its Byzantine source. In their study in the journal Antiquity, the researchers suggest the silver was brought to Europe a hundred years earlier in the form of silver objects, which were melted down and struck as coins in order to put more money into circulation. 
 Bonobos are not as nice as their reputation suggests Bonobos are the lesser-known cousin of chimpanzees, and have a reputation for being the more peaceful ape. But a new study published in Current Biology reveals a dark side of bonobos. Anthropologist Maud Mouginot observed the behaviour of bonobos and chimpanzees in their dense tropical forest habitats in the Democratic Republic of Congo and Tanzania. She was shocked to find out that male bonobos were twice as likely to be aggressive toward other males than chimpanzees. She said this suggests that we need to have a more nuanced view of aggression within and across primate species, including humans.  
 COVID infections are causing brain inflammation, drops in IQ, and years of brain aging For many people COVID was more than a respiratory disease. We’re learning now just what kind of impact an infection can have on the brain. It can affect cognition – leading to the famous brain fog – and even shrink and prematurely age the brain. One of the researchers studying these effects is Dr. Ziyad Al-Aly, he has found COVID patients suffering from brain fog, confusion, tingling, mini strokes, and even seizure disorders. 
 Listener Question – The eclipse and the moon’s temperature. A listener posting as Jeff on X writes: “How hot did the side of the moon that faced the sun get during the eclipse?”  We get the answer from Nikhil Arora, an astrophysicist from Queen’s University in Kingston. 


COVID-19’s “long tail” includes a range of impacts on the brain and more…

Seeing a black hole’s magnetic personality Scientists using the Event Horizon Telescope have produced a new image of the supermassive black hole at the centre of our galaxy. And this image is a little different: it captures the powerful magnetic fields that are acting as the cosmic cutlery feeding mass into the singularity. Avery Broderick is part of the Event Horizon Telescope team, he’s also a professor at the University of Waterloo’s Department of Physics and Astronomy, and associate faculty at the Perimeter Institute for theoretical physics. 
 Decoding how chickadees maintain a mental map of their food caches Chickadees have an uncanny ability to recall thousands of secret stashes of food with a centimetre-scale precision. Salmaan Chettih, a postdoctoral researcher in neuroscience at Columbia University, investigated how chickadees encode their internal treasure maps. In his study in the journal Cell, he found the chickadee brains produce a unique pattern of activity — akin to a neural “barcode” — that marks the X on its mental treasure map.  
 Italians don’t just speak more with their hands, they speak differently Researchers comparing Swedish speakers with Italian speakers have found that the gestures they commonly use to accompany spoken language are quite different in kind. Lund University scientists Maria Graziano and Marianne Gullberg recorded the hand gestures study participants used when describing a children’s cartoon to their friends. According to the results published in a Frontiers in Communication journal, Swedish speakers used gestures that concretely represented the subjects of their speech, while Italian speakers used abstract gestures more related to emphasis.  
 What came first, the drumstick or the omelette? New archaeological work along the famous Silk Road trade route between Asia and Europe has added to the picture of how the chicken was brought from its southeast Asian homeland to the rest of Eurasia. An international team of researchers, including archaeobotanist Robert Spengler, analyzed tiny eggshell fragments from the soil of multiple sites in Central Asia. Their findings, published in Nature Communications, suggest that the motivation for domesticating the fowl was not the chicken, but their eggs.  
 LED lighting is bright, efficient, and perhaps a problem The global transition to LED lighting seems to be having some concerning impacts on the natural world and human health. These energy efficient artificial lights produce different spectra than older incandescent technology, or the natural light of the Sun that life on Earth evolved with over billions of years. LED lighting is brighter, bluer, and more widely used than incandescent lighting.  
 Glen Jeffery, a professor of neuroscience from University College London, said that as a result, we may be paying the price with our health due to being oversaturated with blue light and starved of red and infrared light. In a new study in the Journal of Biophotonics, he found that exposing people to red and infrared light lowered their blood glucose levels by “charging up” our cells’ energy production. 
 Artificial light at night is also having “a profound impact” on our environment in how it affects plants and wildlife and the ecosystems they’re in, according to Kevin Gaston, a professor of biodiversity and conservation at the University of Exeter. He said for nocturnal animals, the challenge they face from light pollution is the equivalent to humans losing daylight during the daytime. His review was published in the Annual Review of Environment and Resources. 

Earliest horsepeople, whales use ‘vocal fry’, plankton might migrate poleward, mapping a fruit fly brain and understanding the cuddly, cute and really strange koala

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