peregrine falcon

<p>See the world through the eyes of nature’s fastest animal: the peregrine falcon. Though once perilously endangered in the U.S., this spectacular predator is now thriving again in American cities and on every continent but Antarctica. What is the secret to its predatory prowess? To find out, follow a young family of peregrines in urban Chicago as the chicks hatch and learn from their parents to fly and hunt. And join expert falconer Lloyd Buck as he trains a captive peregrine and puts its hunting skills to the test. What’s the secret behind the peregrine falcon’s blistering speed, able to reach nearly 200 mph? (Premiered November 21, 2018)</p>

<p>See the world through the eyes of nature’s fastest animal—the peregrine falcon.</p>

World's Fastest Animal

Camila_ferrara_tartaruga P expansa hatchling.jpg

<p>Forty years of community engagement has brought the freshwater turtles of Brazil back from the brink—but lack of funding may imperil conservation.</p>

Amazon Turtles Recovering, Thanks to Local Volunteers

Whit Welles Wikimedia Commons Humpback Whale, breaching, Stellwagen Bank National Marine Sanctuary.jpg

<p>Drowned out by the din of passing ships, humpback whales attempting to breed off the coast of Japan are cutting their conversations short.</p>

Ship Noises Mute the Songs of Humpback Whales

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Nature

Koch Foundation

Draper





  
      <div class="rich-text"><p>It’s a scary world out there.</p><p>That’s why yellow-legged gulls (<i>Larus michahellis</i>) have figured out a clever way to gauge their surroundings while still encased within their speckled eggs. Before they hatch, these birds can tune in to the alarm calls of their parents, who emit a series of signature squawks when they sense the presence of ravenous, chick-chomping mink.</p><p>These chicks then take Mom and Dad’s warnings to heart—and after hatching, they behave in ways that may help them avoid getting eaten.</p><p>But even before busting out of their shells, these little gulls do something else unusual.</p></div>
  

  
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      <div class="rich-text"><p>After hearing their parents’ calls of distress, embryos prepping for potential predators will toss and turn in their eggs. The resulting vibrations, it seems, are then picked up by their unhatched nestmates, which, when they emerge, look and act similarly to their siblings—even if they never got the original memo.</p><p>It’s a bizarre game of avian telephone, and researchers still aren’t completely sure how the underlying process works. But this strikingly sophisticated display of communication, reported in a <a href="https://www.nature.com/articles/s41559-019-0929-8">study</a> published today in the journal <i>Nature Ecology &amp; Evolution,</i> reinforces the notion that eggs are more than passive embryonic vessels. The findings also suggests that, by picking up subtle signals from siblings, chicks-to-be can prep for hardship without actually having to experience it firsthand.</p><p>“Any information an animal gleans from its environment...will help it prepare for the world it’s about to be born into,” says <a href="http://calisilab.ucdavis.edu/">Rebecca Calisi Rodríguez</a>, a bird behavioral biologist at the University of California, Davis who was not involved in the study. “But the mind-blowing thing here is that there’s communication between siblings...in a way that changes how all of them develop.”</p>
            <figure class="richtext-image full-width"><img alt="combo pip.jpg" class="richtext-image full-width" height="599" width="800"
            src="/wgbh/nova/media/images/combo_pip_copy.width-800.jpg"/><figcaption><p>Yellow-legged gull chicks. Adults will lay eggs days apart, resulting in clutches of embryos at different stages of development. Image Credit: Jose C. Noguera, University of Vigo</p><div class="credit"><p></p></div></figcaption>
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            <p>This isn’t the first time researchers have eavesdropped on animals chattering at their unborn offspring. In 2016, Deakin University researchers <a href="https://www.deakin.edu.au/about-deakin/people/mylene-mariette">Mylene Mariette</a> and <a href="https://www.deakin.edu.au/about-deakin/people/kate-buchanan">Katherine Buchanan</a> discovered that rising temperatures can prompt adult zebra finches to <a href="https://science.sciencemag.org/content/353/6301/812">belt out ballads</a> that broadcast the warm conditions to their eggs, which in turn hatch chicks better adapted to the heat. Others have shown that siblings, too, can convey prenatal messages to their nestmates—and several <a href="https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1439-0310.1999.10512489.x">birds</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4796811/">reptiles</a>, and <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(18)31490-8">insects</a> are known to coordinate hatching times through cues passed from egg to egg.</p><p>But neither of these processes is well understood, and they’ve never been linked together like this in the same species, says study author <a href="https://sites.google.com/view/josecnoguera/home">Jose Noguera</a>, a behavioral ecologist at the University of Vigo in Spain.</p></div>
  

  
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      <div class="rich-text"><p>So Noguera and his advisor, <a href="http://avelando.webs.uvigo.es/alberto.html">Alberto Velando</a>, decided to see if eggs could act as yolky intermediary in ferrying crucial intel—like the presence of a predator—from parent to offspring to sibling.</p><p>Such a familial relay might seem redundant, since all the eggs in a single nest should be exposed to the same cries. But some birds, like the yellow-legged gull, lay their eggs several days apart, which means each embryo in a given nest is at a different point along its developmental trajectory.</p><p>Because hearing crystallizes relatively late in development, older siblings are better equipped to receive their parents’ vocal warnings. Touch, on the other hand, is an early-emerging sense—which could make inter-egg vibrations a way to get a hard-to-hear message across to the junior members of a clutch, Noguera says.</p><p>To test this theory, Noguera and Velando gathered 90 second-laid yellow-legged gull eggs—the natural middle children of clutches—and divvied them up into 30 trios. During each day of the eggs’ last week of development, the researchers briefly exposed two of the eggs in each clutch to either recordings of adult alarm calls or static from a speaker, then returned them to incubate with an undisturbed foster sibling.</p><p>Clutches whose eggs weren’t privy to the prenatal panic yielded uniformly carefree chicks. But embryos that had regularly encountered alarm calls took longer to emerge from their eggs—and though they eventually hatched, these chicks never fully came out of their figurative shells. Their blood brimmed with stress hormones, and they were quieter and quicker to hide when they heard more of the adults’ cautionary caws. There were even changes in how the chicks broadly expressed different sets of genes.</p><p>And the hatchlings didn’t just internalize these subliminal messages: They passed them on to their uninformed siblings, too. After listening to squawks of distress, eggs shook and shimmied, knocking up against their nestmates—which then made moves of their own.</p>
            <figure class="richtext-image full-width"><img alt="35805201206_14cce4a62f_o.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/35805201206_14cce4a62f_o.width-800.jpg"/><figcaption><p>A trio of yellow-legged gull chicks in Galicia, Spain. Image Credit: Contando Estrelas, flickr</p><div class="credit"><p></p></div></figcaption>
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            <p>These secondhand signals, Noguera says, were enough to seal the fates of the unexposed chicks—even in the absence of direct auditory input. From blood to behavior, these eggs and the hatchlings they bore were identical to their stressed-out siblings by every metric measured.</p><p>“It’s not just about what happens to you during development,” Noguera says. “It matters what happens to your siblings, too.”</p><p>Because the researchers didn’t follow the chicks into adulthood, it’s difficult to say just how adaptive these behavioral and physiological changes were, says Mariette, who wrote a <a href="https://www.nature.com/articles/s41559-019-0955-6">commentary</a> to accompany the study, which she wasn’t involved in. (The changes also probably come with costs, she notes: For instance, chicks exposed to alarm calls—both directly and by proxy—grew slower and were smaller than their counterparts.)</p><p>However, the sophisticated demonstration of clutchmate coordination still sets this paper apart, Mariette adds. Unhatched chicks aren’t just <i>aware</i> of the world around them; they’re able to convey information about it, too. “Embryos are really not as isolated as we tend to think of them,” she says.</p>
            <figure class="richtext-image full-width"><img alt="3 chicks.JPG" class="richtext-image full-width" height="600" width="800"
            src="/wgbh/nova/media/images/3_chicks.width-800.jpg"/><figcaption><p>Yellow-legged gull chicks huddled in their nest. Image Credit: Jose C. Noguera, University of Vigo</p><div class="credit"><p></p></div></figcaption>
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            <p>Fussy bird parents might deliberately chirp at their eggs to convey information. But Noguera cautions that the study’s findings don’t necessarily mean that unhatched siblings are engaging in any kind of <i>intentional</i> conversation among themselves. Rather, there’s a good chance these eggs are just sponging up whatever intel they can get. And though he hasn’t yet shown it for this species, Noguera thinks there are probably other cues, such as smells, that might play a role in the prenatal avian milieu.</p><p>That might not be all that surprising, given how sensitive other <a href="https://www.pbs.org/wgbh/nova/article/prozac-may-transcend-generations/">embryos</a> (including those of <a href="https://www.pbs.org/wgbh/nova/article/male-twin-might-change-the-trajectory-of-a-womans-life/">humans</a>) are to their environments. But when it comes to the nuclear family, knowledge may flow more freely than once thought. The routes it takes probably aren’t always direct—and maybe that’s the point.</p><p>“We’re subconsciously gathering information from each other all the time,” Calisi Rodríguez says. “There’s that saying: ‘By failing to prepare, you are preparing to fail.’ By having these particular capabilities, these organisms are preparing to succeed.”</p></div>
  

  
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<p>Even while still in their eggs, baby birds can hear their parents’ alarm calls. They then pass the message along to unhatched siblings so the entire clutch emerges aware of the dangers ahead.</p>

Quivering bird eggs prep each other for predators before they hatch





  
      <div class="rich-text"><p>In 2013, a deadly swine virus popped up on a handful of U.S. pig farms and quickly spread to 30 states. Over the next year, it wiped out around 10 percent of the U.S. pig population, and <a href="https://www.nationalhogfarmer.com/animal-well-being/economic-impacts-pedv">pork prices jumped.</a></p><p>This was the first appearance of porcine epidemic diarrhea virus (PEDV) in the United States. And although this particular outbreak was mostly contained in 2014, the virus remains a lingering threat to pig farms: An outbreak can cost a farm about $300,000 once dead pigs have been replaced and barns disinfected.</p><p>The virus, which does not affect humans, is spread through pig feces. Scientists still don’t understand exactly what triggers, or perpetuates, an outbreak. But that may be changing.</p></div>
  

  
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      <div class="rich-text"><p>After the initial outbreak, North Carolina State University epidemiologist <a href="https://cvm.ncsu.edu/directory/machado-gustavo/">Gustavo Machado</a>, along with colleagues from the University of Minnesota and Brazil’s Universidade Federal do Rio Grande do Sul, set out to study PEDV in sow farms across the United States. Using data on the virus’ prevalence in farms, pigs’ movements between farms, and environmental factors like wind speed and temperatures, they developed an algorithm to predict PEDV outbreaks. They used data from 2014 to “predict” outbreaks on a week-by-week basis, testing their results against what had actually unfolded each week.</p><p>In a <a href="https://www.nature.com/articles/s41598-018-36934-8">study</a> published in January in the journal <i>Nature</i>, Machado’s team showed that its algorithm was able to predict whether a PEDV outbreak would occur during a given one-week period with about 80 percent accuracy. They also determined that the movement of pigs between farms was the most important factor in the spread of the virus, but there may also be a risk of airborne spread.</p><p>“What we know is about 75 percent of the PEDV outbreak is reasoned by the movement of animals and the proximity with other farms,” Machado says. Pigs carrying PEDV can infect both their barn mates and pigs at nearby farms.</p><p>The virus infects the cells that line pigs’ small intestines, causing severe diarrhea and dehydration. The symptoms come on quickly and run a short—and sometimes severe—course. Piglets younger than a couple weeks old are most vulnerable, and often die from dehydration, diarrhea, and vomiting.</p><p><a href="https://www.vetmed.wisc.edu/people/kbernard/">Kristen Bernard</a>, a virologist at the University of Wisconsin-Madison’s School of Veterinary Medicine who was not involved in the latest study, says <a href="https://journals.sagepub.com/doi/full/10.1177/1040638713501675?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub%25253dpubmed">genomic sequencing studies</a> of PEDV suggest it originated in from a viral strain in China in 2012. <a href="https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0194509&amp;type=printable">Experts</a> suggest that PEDV may have spread to the U.S. through animal feed ingredients from China.</p><p>“It wouldn’t have been carried in the wind or water or anything like that,” Bernard says of the first U.S. outbreak. “And the fact that [initial PEDV infections] happened almost within days of each other, it’s very unlikely that it was transferred from farm to farm.” But, Bernard says, concrete evidence that PEDV came from China is still lacking.</p></div>
  

  
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      <div class="rich-text"><p>A vaccine for the virus exists, but it isn’t 100 percent effective. The vaccine does boost the herd immunity of piglets, Machado says, but researchers have found traces of PEDV in piglet fecal samples from farms where vaccination occurred.</p><p>This could be because of how the vaccine is administered, Machado says: Veterinarians vaccinate sow mothers for PEDV rather than injecting piglets directly. Mothers pass antibodies against the virus to their offspring through their milk, which should protect them from infection. But this doesn’t always pan out.</p><p>“They have immunity, but maybe it’s not enough,” Machado says of the piglets. “What we really don’t understand is if the immunity is enough to protect for a new outbreak.”</p><p>Machado says additional measures, like installing air filters, can potentially reduce the circulation of the virus. Meanwhile, his lab continues to gather data weekly from 50 percent of U.S. sow farms to model the virus’ spread.</p><p>Based on the lab’s data, Machado predicts a 10 percent decrease in PEDV in the next two years.</p><p>The swine farms that participate in Machado’s study can receive an algorithm-based prediction of any upcoming outbreaks of PEDV and other diseases.And Machado’s team is developing an online portal in which farmers can check to see if their farm is within a PEDV outbreak-expected zone. The researchers believe this will encourage precautionary measures and enable farmers to address any PEDV outbreaks immediately.</p><p>Machado also hopes to figure out why PEDV outbreaks still occur in regions where virus immunity seems to be high. “We don’t know,” he says. “Maybe the virus is inside the farm circulating at low prevalence and then something happens, and then we have [an] explosion of the virus again.”</p><p>To find answers, he and his team aim to continue to study PEDV and model its spread for another five or 10 years. Currently, they are looking into other factors that might be associated with the virus spread, including the movement of feed mill trucks into farms.</p><p>Epidemiological models like Machado’s, Bernard says, extend beyond PEDV. Analyzing pigs’ movement and population as well as factors like food and water contamination, “can be really applicable to lots of different diseases,” she says. “That’s what’s useful about these kinds of epidemiological models,” she continues. “It’s to help us know what to do in the face of a new outbreak.”</p></div>
  

  
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<p>A swine virus that appeared in the U.S. in 2013 has proven hard to track. But an algorithm might help researchers predict the next outbreak.</p>

This algorithm is predicting where a deadly pig virus will pop up next





  
      <div class="rich-text"><p>If you’re an organism with a hankering for flesh, a few things can come in handy. Fast feet, for one, to give chase, and maybe some claws and a sharp set of teeth. Good vision doesn’t hurt, either—especially when it’s teamed up with a keen nose and big, sensitive ears.</p><p>Unfortunately, the carnivorous Venus flytrap (<i>Dionaea muscipula</i>), which dines on bugs and spiders to compensate for the nutrient-poor soil of its natural wetland environment, has none of these lethal assets at its disposal.</p><p>But there’s no need to pity these predatory plants: An exquisite sense of touch is all it takes for Venus flytraps to snare their tiny prey. That’s all thanks to the sensory capabilities of a few stiff, sensitive hairs poking out from the inner surfaces of their mouth-like leaves—each tuned to discern the infinitesimally small shudders of an insect on the go. Now, scientists have finally put numbers to just how perceptive these trigger-happy hairs can be.</p></div>
  

  
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      <div class="rich-text"><p>A <a href="https://www.nature.com/articles/s41477-019-0465-1">study</a> published today in the journal <i>Nature Plants</i> shows that Venus flytrap hairs are sensitive enough to detect critters that weigh as little as 3 milligrams—less than a typical sesame seed. While this threshold may exclude the most petite of prey species, having a size cutoff may actually help the plant avoid meals too small to be worth the trouble.</p><p>When vacant, a Venus flytrap leaf resembles an open pairs of jaws. In reality, each trap is an entire digestive tract collapsed into a single, bi-lobed pouch, rimmed with fang-like protrusions. Studding the inside of the trap are a handful of thin, rigid hairs, each attached to a flexible base that can register the movements of the rod above—a bit like a joystick.</p><p>This unusual setup allows the hairs to function like tripwires. When something bumps up against them, electrical signals spread through the trap’s leafy lobes. Digestion then proceeds in a series steps: First, the trap slams shut; then, it hermetically seals. Eventually, the now-airtight chamber will flood with flesh-melting fluid, transforming whatever’s inside into sticky sludge.</p><p>Once this process begins, it can take over a week for the trap to reopen—making mistakes very costly.</p>
            <figure class="richtext-image full-width"><img alt="Venus_Flytrap_showing_trigger_hairs.jpg" class="richtext-image full-width" height="545" width="800"
            src="/wgbh/nova/media/images/Venus_Flytrap_showing_trigger_hairs.width-800.jpg"/><figcaption><p>The inside of a Venus flytrap trap is studded with a small handful of thin, stiff hairs that can be triggered by touch. Image Credit: Noah Elhardt, Wikimedia Commons</p><div class="credit"><p></p></div></figcaption>
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            <p>Luckily, the Venus flytrap has evolved a few safeguards to avoid responding to false alarms like breeze-borne debris, or the pitter-patter of intermittent raindrops. Three years ago, a team of researchers led by <a href="https://www.biozentrum.uni-wuerzburg.de/en/bot1/research/prof-dr-rainer-hedrich/">Rainer Hedrich</a>, a plant physiologist at the University of Würzburg in Germany, discovered that traps can <a href="https://www.cell.com/current-biology/fulltext/S0960-9822(15)01501-8">“count” the number of times their hairs are nudged</a>. Each bump triggers its own electrical impulse—and the more times the hairs are touched in a row, the further along the path of consumption the plant will progress. Two touches, and the two halves of the leaf come together in a loose cage; a third zippers them tightly shut. A few more, brought on by the catch struggling within, and the whole contraption morphs into an acidic stomach, liquifying its contents.</p><p>Before any of this can happen, though, a trap’s hairs need to know when it’s appropriate to sound the alarm. “It was a simple question,” says study author <a href="https://wueaddress.uni-wuerzburg.de/person/23336">Sönke Scherzer</a>, who conducts research under Hedrich’s supervision. “But we just wanted to know how sensitive these hairs really are.”</p></div>
  

  
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      <div class="rich-text"><p>To define the limits of flytrap touchiness, Scherzer and his colleagues hooked a series of plants up to a computer that monitored their electrical activity. They then used a small, motorized device to flick the trap’s hairs, all the while looking for the subtlest movements sufficient to trigger a response.</p><p>It didn’t take much. For a signal to be sent, a tilting hair had to meet three criteria: It needed to bend more than 2.9 degrees, move fast enough to traverse at least 3.4 degrees within the span of a second, and feel a force of at least 29 micronewtons (roughly equivalent to being stepped on by a three-milligram bug, like a small mosquito).</p><p>These numbers, Scherzer says, matched up nicely with what the hairs experienced when the researchers allowed them to be trampled by a colony of ants—a common meal for wild flytraps.</p><p>Though several of the team’s findings are pretty intuitive, their paper is the first to quantitatively assess how these hairs are triggered, says <a href="https://biology.wustl.edu/people/barbara-pickard">Barbara Pickard</a>, an expert in plant sensory physiology at the Washington University in St. Louis who was not involved in the study. “Plant mechanosensing [response to detection of touch] is far more generalized and sensitive than people realize,” she says.</p><p>Not all traps are created equal, however. Each Venus flytrap hosts several sets of “jaws” of different sizes—and they don’t appear to behave in the same way. In the study, the researchers found that larger traps contained hairs that were both thicker at the base and less sensitive than those in smaller traps.</p>
            <figure class="richtext-image full-width"><img alt="iStock-118316941.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/iStock-118316941.width-800.jpg"/><figcaption><p>On a Venus flytrap, bigger traps have less sensitive trigger hairs, biasing them toward larger prey. Image Credit: Jim1123, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>From a physical standpoint, this simply reflects the fact that bulkier hairs are more difficult to bend. But there may be an evolutionary impetus behind this adaptation as well, points out <a href="https://laurahamonsite.wordpress.com/">Laura Hamon</a>, a Venus flytrap researcher at North Carolina State University who was not involved in the study.</p><p>While the teeniest traps can still get a nutritious meal out of insects and spiders weighing only a couple milligrams, it may be less advantageous for larger traps to invest in such puny portions. The higher threshold of big traps, then, might function as a precaution that prevents them from biting off less than they can chew, Hamon says.</p><p>Pickard supports the notion of size selection, highlighting the work of plant biologists <a href="http://www.hartmeyer.de/">Siegfried Hartmeyer</a> and <a href="https://www.researchgate.net/profile/Stephen_Williams21">Stephen Williams</a>, which indicates that Venus flytraps have an entire suite of traits to help them avoid unsatisfying meals. “Closing and reopening the trap takes a lot of the leaf’s available energy,” she says. “So catching small prey can be a net loss.”</p><p>According to Hartmeyer and Williams’ research, which is currently being submitted for peer-reviewed publication, the plants may use specialized scent glands to lure especially tiny prey, like certain types of ants, to the edges of their traps and away from the trigger hairs. Even after the leaf shuts, bugs small enough to slip out of the leaf’s gap-toothed grin are able to escape before the trap seals completely.</p>
            <figure class="richtext-image full-width"><img alt="DSC09485 copy.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/DSC09485_copy.width-800.png"/><figcaption><p>Even after a trap first closes, it doesn&#x27;t seal completely shut until its hairs are triggered again. Small prey can escape through the sparsely-spaced prison bars. Image Credit: Courtesy of Sönke Scherzer, University of Würzburg</p><div class="credit"><p></p></div></figcaption>
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            <p>All this goes to say that Venus flytraps may be even more calculating killers than once thought. “Plants are a lot more complex than we give them credit for,” says <a href="https://pages.wustl.edu/haswell/people/angela-schlegel">Angela Schlegel</a>, who studies mechanical signals in plants at Washington University in St. Louis, but was not involved in the study. “This paper is a highlight of how we can study that complexity.”</p></div>
  

  
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<p>Good news for bugs that weigh less than a sesame seed.</p>

Venus flytraps’ ultra-sensitive hairs help determine if an insect is worth trapping





  
      <div class="rich-text"><p>Like humans, octopuses are incredibly intelligent. But an octopus’ mind is about as alien to the human mind as the human mind is…well, to an alien’s.</p><p>“I like to [ask], ‘How are they intelligent?’ rather than ‘How intelligent are they?’” says Dominic Sivitilli, a behavioral neuroscientist and astrobiologist at the University of Washington who presented a new octopus cognition model at <a href="https://connect.agu.org/abscicon/home">the AbSciCon 2019 conference</a> this week.</p></div>
  

  
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      <div class="rich-text"><p>The model is designed to illustrate how octopuses process information, and Sivitilli believes it could eventually provide insight into how non-human intelligence evolved here—and possibly elsewhere in the universe.</p><p>Octopuses have problem-solving abilities similar to those observed in corvids (the group of birds that includes crows, ravens, and jays), parrots, and primates. But the way these eight-armed enigmas process information is completely different. Unlike humans and other vertebrates, which centralize mental processing in the brain, octopuses and other cephalopods use neurons throughout their suckers, arms, and brain to understand their world.</p><p>“What we’re looking at, more than what’s been looked at in the past, is how sensory information is being integrated in this network while the animal is making complicated decisions,” said David Gire, lead researcher on the project and neuroscientist at the University of Washington, in a statement.</p><p>The unique nature of octopus intelligence has sparked a rather peculiar debate recently: A group of researchers (not associated with Gire and Sivitilli’s study) has suggested that an octopus’ mind might seem so foreign because it may be alien. The hypothesis, <a href="https://www.sciencedirect.com/science/article/pii/S0079610718300798">published in 2018</a>, states that octopus evolution may have arisen, in part, because of a retrovirus (a type of RNA virus) delivered to Earth by an asteroid during <a href="https://phys.org/news/2019-06-plate-tectonics-driven-cambrian-explosion.html">the Cambrian explosion</a> about 541 million years ago.</p><p>But as alien as an octopus’ intelligence may seem, Sivitilli is careful to point out that they’re “definitely, based on the evidence in front of us, related to us at some point in our history.”</p><p>“I do not think that octopuses are aliens,” he says.</p>
            <figure class="richtext-image full-width"><img alt="DSC_8499-2.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/DSC_8499-2.width-800.jpg"/><figcaption><p>A Giant Pacific octopus at the New England Aquarium in Boston, Mass. Image credit: AJ Fillo, WGBH</p><div class="credit"><p></p></div></figcaption>
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            <p>Because of octopuses’ distributed mental structure, scientists have long said that each octopus arm has a mind of its own. But it may be even more accurate to say that each <i>sucker</i> has its own brain, Sivitilli says. “There are tens of thousands of both chemical and mechanical receptors in each sucker,” he says. “To put that into perspective, each of your fingertips has a few hundred mechanical receptors.”</p><p>To track how their arms think, Gire and his team <a href="https://youtu.be/6laZ9ad-D54">filmed captive octopuses</a> as they explored new objects in their enclosures. With the footage in hand, the researchers used a computer algorithm to determine if the arms were working together, which would suggest central direction from the brain, or independently, which would suggest the arms were making decisions on their own.</p></div>
  

  
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      <div class="rich-text"><p>The results, which are preliminary, show octopuses’ arms working both with the brain and on their own. But they also suggest that individual suckers can process information independently—something scientists had previously only hypothesized.</p><p>The team found that if one of an octopus’ suckers finds something interesting, like food, it triggers a sucker next to it to double check. If that sucker is also interested in the potential treat, it triggers the next one. This creates a cascade of neurons down the arm’s ganglia (nerve cell clusters), encouraging the octopus’ arm to then wrap around the item of interest.</p><p>This entire process bypasses the animal’s brain—but the system isn’t perfect. Because the suckers can act independently of the brain there’s not always consensus, Sivitilli explains. “Sometimes, the arm plays tug of war with itself,” he says.</p><p>“This is really exciting work,” said Jennifer Mather, a behavioral psychologist specializing in cephalopods at the University of Lethbridge who was not involved in the study, in an email.</p><p>But, she says, “they haven’t shown that the arms ‘make decisions.’”</p><p>Scientists have known that octopuses can pass information from arm to arm, bypassing the brain, for years. What they don’t yet understand is how the arms are able to process that coordination.</p><p>Because this study is based only on video observations, Mather says, it doesn’t track the neural information being passed between and within the arms.</p><p>Still, “thinking” with an arm is an impressive feat, Sivitilli says. And, better understanding the way octopuses process information—whether with an arm or their actual brain—may help us better understand other forms of intelligence radically different from our own, including any that may exist elsewhere in the universe, he says.</p><p>Octopuses are clearly from Earth, but that doesn’t mean they can’t teach us something about the stars, Sivitilli believes. “Studying models of cognition on Earth, especial those along different evolutionary paths, can really contextualize the search for extraterrestrial intelligence.&quot;</p></div>
  

  
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<p>Octopuses “think” with neurons so distributed throughout their bodies that sometimes the left hand literally doesn’t know what the…left hand is doing.</p>

Thinking is for suckers, but if you’re an octopus, suckers are for thinking





  
      <div class="rich-text"><p>An elephant nose is nothing to sneeze at.</p><p>Rippling with <a href="https://nationalzoo.si.edu/animals/asian-elephant">150,000 individual units of muscle and tendon</a>, the trunks of these behemoths are veritable Swiss army knives of functionality, deployed for everything from feeding to fighting. Each trunk can store up to two gallons of water, and has the <a href="https://www.rosamondgiffordzoo.org/assets/uploads/animals/pdf/AsianElephant.pdf">strength to lift hundreds of pounds</a> and the dexterity to crack a single nut from its shell.</p><p>But these supersized snoots are constantly serving up surprises—and a group of researchers has now discovered that they’re discerning enough to distinguish more from less. Their <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1818284116">study</a>, published today in the journal <i>PNAS,</i> suggests elephants can use scent alone to differentiate between quantities of sunflower seeds that might flummox even the most hawk-eyed of humans.</p><p>“This is a very impressive paper,” says <a href="https://www.wits.ac.za/apes/research/alexander-herp-lab/">Ashadee Kay Miller</a>, a biologist at the University of the Witwatersrand in South Africa who was not involved in the study. “I think they’ve gone through a lot of effort to show that what they’ve found is genuine.”</p></div>
  

  
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      <div class="rich-text"><p>While it’s still not clear exactly <i>how</i> elephants sniff out larger quantities, the scientists’ findings reinforce the idea that elephants depend heavily on odors to guide their behavior—and may help scientists study their cognitive capabilities in the future.</p><p>Olfaction, or sense of smell, remains vastly understudied compared to senses humans rely on more, like vision and hearing. People are naturally biased toward studying what we know—and a lot of what we know comes from what we see. But elephants are among the many animals for which sight is a second-class sense.</p>
            <figure class="richtext-image full-width"><img alt="iStock-987375498.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/iStock-987375498.width-800.jpg"/><figcaption><p>Elephant trunks are incredibly versatile, helping their owners breathe, smell, touch, grasp, produce sound, and spray water, dust, or grass. Elephants can even use their trunks to snorkel while crossing bodies of water. Image Credit: HandZaround.com, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>Studies have shown that elephants boast <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4158756/">more than 2,000 genes</a> coding for olfactory receptors—the most of any mammal tested to date (for comparison, humans have only 400). Elephant noses are sensitive enough to <a href="https://www.sciencedirect.com/science/article/abs/pii/S0168159115002063">detect TNT</a>, and <a href="https://www.sciencedirect.com/science/article/pii/S0960982207020660">distinguish between tribes of humans</a> that have traditionally treated them well and groups that have acted aggressively. They even have the precision to discriminate between <a href="https://academic.oup.com/chemse/article/38/2/107/332786">structurally similar molecules</a> that are mirror images of each other—a subtle difference that would stump the schnozzes of humans and other primates.</p><p>But these stunning discoveries likely only scratch the surface, and the true limits of elephants’ olfactory prowess remain mysterious.</p></div>
  

  
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      <div class="rich-text"><p>To fill in some of the gaps, a team of researchers led by <a href="http://www.hunter.cuny.edu/psychology/people/faculty/physiological/plotnik">Joshua Plotnik</a>, a comparative psychologist at Hunter College, City University of New York, decided to see whether six captive Asian elephants (<i>Elephas maximus</i>) could use odors alone to make quantitative judgments.</p><p>After training their subjects to seek out containers with larger amounts of food, Plotnik and his team presented each elephant with a pair of locked, opaque buckets containing two different quantities of sunflower seeds. While the elephants couldn’t see the seeds, they could still catch a whiff of each container’s contents through perforations in its lid. After a brief period of investigation, the buckets were unlocked so the elephants could indicate their choice by removing the lid from one container.</p><p>Across 11 different ratios of seeds, the elephants were, on average, able to pick out the larger helpings of food. While the elephants did their best work when the disparities between quantities of food were larger—for instance, when selecting 24 grams of seeds over 4 grams (roughly 180 and 30 seeds, respectively)—their performance steadily diminished as the differences between seed portions shrank. Overall, however, “they did pretty well,” Plotnik says. “A couple of the elephants were even able to tell [approximately] 180 seeds from 150, and that’s remarkable.”</p><p>Ensuring that the elephants were using only scent-based cues, however, required some creativity, in part because smells tend to linger. But when the researchers replaced their plastic buckets for metal receptacles that might be less likely to retain odors, or repeated their tests with containers that had previously held vastly different numbers of seeds, the results still held true.</p><p>The team also ruled out the possibility that their study subjects were picking up on inadvertent cues from the researchers by adding an experiment in which they hid the quantities of seeds from human and elephant alike. In a final trial, the team even positioned the buckets in a way that equalized the height of the top of each seed pile to keep the elephants from picking the portion closer to their trunks. In spite of all these changes, the elephants continued to home in on the more generous portions.</p><div style="padding-bottom: 56.25%;" class="responsive-object">
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<p>One condition did strip the elephants of their ability to detect the aroma of abundance: swapping out the perforated lids for solid ones that scents couldn’t pass through. This, Plotnik says, hints strongly at the incriminating culprit being smell alone.</p><p>“I’m really glad to see a study like this done,” says <a href="http://www.caitlineoconnell.com/">Caitlin O’Connell</a>, a biologist and elephant expert at Stanford University who was not involved in the study. “I know how difficult these studies are, but these experiments are really nicely set up. They leave little left to be questioned about whether what they see [is real].”</p><p>Because the elephants in the study weren’t free-living, it’s not yet clear how these behaviors translate to wild populations, or how they’d benefit elephants in social or ecological contexts, says <a href="http://marcelabenitez.weebly.com/">Marcela Benítez</a>, a behavioral biologist at Georgia State University who was not involved in the study. But smell can have a lot of advantages over vision. “When you have visual stimuli, it’s only as good as what’s in front of you,” she says. “It doesn’t travel well. But something like scent can remain...it has a temporal element you don’t get with vision.”</p>
            <figure class="richtext-image full-width"><img alt="iStock-534789901.jpg" class="richtext-image full-width" height="550" width="800"
            src="/wgbh/nova/media/images/iStock-534789901.width-800.jpg"/><figcaption><p>Elephants are highly social. Their trunks help them communicate through sound, smell, and touch. Image Credit: Kyslynskyy, iStock</p><div class="credit"><p></p></div></figcaption>
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            <p>And given how smell-oriented elephants are in navigating their surroundings, it’s likely they’re putting these appendages to good use in daily life, O’Connell says. Quantitative trunks could come in handy for locating rich caches of food, or keeping track of a herd. They could also help elephants identify potential mates or avoid conflicts with competitors. “It’s critical for elephants to understand their world through smell,” she says. “For them to be able to distinguish quantity makes a whole lot of sense.”</p><p>What exactly “more” or “less” smells like at the cellular level, and how this information gets processed in the brain, still aren’t clear. (Though, based on the study’s results, it’s probably unlikely that elephants can sniff a container and tell the exact <i>number</i> of seeds inside.) Answering these questions will require more research—and, given our own limitations in the odor department, a hefty dose of creativity. “[Understanding how to smell quantity] might be like describing colors to someone who’s never seen before,” Miller says.</p><p>Understanding this sensory skill, however, could help preserve a species in decline. Fewer than 40,000 Asian elephants remain in the wild—and “we’re running out of time to save them,” Plotnik says. “They’re remarkably intelligent animals we still know very little about.”</p><p>But conservation will be difficult without clearer insights into how these animals see—and smell—the world around them. “If you want to really understand how smart an animal is, you have to put yourself in their shoes,” Plotnik says. “What this study tells us is, if you want to do that with an elephant, you’re going to need a trunk.”</p></div>
  

  
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<p>Their amazing sense of smell allows them to discriminate between quantities of sunflower seeds that human eyes would have difficulty telling apart.</p>

Elephants can use scent to distinguish more from less

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<p>To milk a horse, one must trick a mother horse—and trick her well.</p>
<p>Anthropologist and filmmaker Niobe Thompson attempts to milk a horse, and discovers that the process is a lot more difficult than it sounds. Milking a mother horse, he explains, is all about tricking her. The process begins by having her foal suckle. Then, the foal is taken away and a human rushes in to take its place. But if the mother horse suspects anything is different, things can go awry.</p>
<p><b>Milking a Horse is Harder than You Think</b></p><p>Published: May 15, 2019</p><p></p><p><b>Niobe Thompson</b>: Milking a horse is all about tricking the horse. So what happens is, someone brings a foal in, the foal sucks the milk from the teats, the milk falls. And then they pull the foal away quickly, and someone rushes in and milks the horse.</p><p>As soon as the mare knows that it’s not the foal or suspects something—something’s different—the milk dries up. The mare sensed that I didn’t really know what I was doing. As soon as I got a bit of milk out, the teats dried up. They had to bring the foal back in.</p><p>It’s really hard. It’s just—just a little bit.</p>
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<p>To milk a horse, one must trick a mother horse—and trick her well.</p>

Milking a Horse is Harder than You Think





  
      <div class="rich-text"><p>On feeding days, <a href="https://www.blackledgelab.com/labmembers#/current-lab-members-1">Sarah Han</a> would lift the lid to the spider enclosure and carefully lower a struggling fly to its doom.</p></div>
  

  
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      <div class="rich-text"><p>It only took a few tries for Han, an entomologist at the University of Akron, to notice some unusual behavior in her triangle-weaver spiders (<i>Hyptiotes cavatus</i>). Each time an insect brushed up against the silk, the arachnid stationed at one corner of its triangular trap would jerk in the direction of its prey, releasing the tension in the web. With each successive movement, the web’s infrastructure would crumple inward like a snapped rubber band, instantaneously shrouding the hapless fly in a billowing sheet of sticky, immobilizing silk.</p><div style="padding-bottom: 56.25%;" class="responsive-object">
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<p>The spiders’ shudders were subtle, but more than anything, they were <i>fast.</i> When Han filmed the spiders on high-speed video and played the tape back in slow motion, she discovered the spiders were launching themselves and their webs with accelerations up to 1,700 miles per hour per second (that is, their speed increased by 1,700 miles per hour each second). That’s about 60 times the acceleration of a sprinting cheetah. Every time they did, the spiders boosted their chances of snagging themselves an expedient meal.</p><p>Today, in the journal <i>PNAS,</i> Han reports <a href="https://www.pnas.org/cgi/doi/10.1073/pnas.1821419116">the secret to these spiders’ success</a>: A sophisticated ability to use their webs as “tools” to exceed the limitations of their own bodies—akin to a human shooting an arrow from a tightly-drawn bow.</p><p>“This is a pretty awesome thing to see,” says <a href="https://www.bhamla.gatech.edu/members">Symone Alexander</a>, an entomologist and biophysicist at Georgia Tech who was not involved in the study. “These spiders don’t have superpowers like supervision or jumping. Their strategy is more, ‘How can we use a tool to catch a meal that’s much larger, faster, and stronger than we are?’”</p><p>For many other spiders, mealtimes can be a bit of a gamble. Even if an insect stumbles into a freshly woven web, there’s no guarantee it’ll stick. This puts the onus on the hungry arachnid to quickly scuttle down its silk ladder and secure its prey with a secondary straightjacket before the insect wrests itself free. And in doing so, a soft-bodied spider risks being injured by its tenuously trapped prey.</p><p>That’s why the triangle weaver’s slingshot strategy is so effective. Rather than risking their hides through physical contact with their prey, these spiders leverage their webs to subdue insects from afar.</p><p>After spinning its web, a triangle weaver spider will take up residence at one corner of its contraption and secure itself to a nearby branch with a silken anchor line. While gripping its web with its front legs, the spider then hauls itself up the anchor line in the direction of the branch, gathering the slack of its tether. The movement tugs the trap as taut as a translucent trampoline, storing energy in the spider’s super-strong silk.</p><p>Then, when an insect smacks into the trap, the spider releases its anchor line, sending itself and the web hurtling forward like an unspooling bungee jumper, collapsing silk around its prey. When the spider reaches the end of its rope, it recoils and ricochets, sending a second wave of fibers cascading around the bedeviled bug from every direction. The triangle weaver can then repeat the cycle several times over by simply ratcheting back along its anchor line and letting go again, until the entire web has become an inescapable clump of silky shrink wrap.</p><div style="padding-bottom: 56.25%;" class="responsive-object">
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<p>Before Han and her team decided to investigate, however, no one had put actual numbers to these spiders’ fleet-footed tricks. Their analysis revealed that the initial release could tangle a fly in as few as four milliseconds. Even with multiple rounds of aim and fire, the spiders didn’t need more than a few seconds total to fully snare their snacks.</p><p>Han was astounded to find that the energy wound up in the spiders’ silk could propel them forward with accelerations that would <a href="https://www.pbs.org/wgbh/nova/article/gravity-forces/">shred human innards</a> (even accelerating at just 90 miles per hour per second can cause the average person to lose consciousness). At maximum speed, the rice-sized spiders, measuring close to 5 millimeters long, were covering 400 times the lengths of their own bodies each <i>second</i>—the equivalent of a 5’10” human sprinting at more than 1,500 miles per hour.</p></div>
  

  
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      <div class="rich-text"><p>The spiders didn’t always deploy their webs when a fly made contact. If this was the case, Han found, the insect inevitably flew away. But when the web was cast, the spider’s rate of success jumped to more than 70 percent. By tapping into the power of their netlike webs, the triangle weavers had found a way to rapidly incapacitate their prey without running the risk of a physical brawl.</p><p>“This tiny little animal just cranks up stored energy in its web and turns it into...a controllable prey-catching device,” says <a href="https://pateklab.biology.duke.edu/users/sheila-patek">Sheila Patek</a>, a biophysicist and biomechanics expert at Duke University who was not involved in the study. “It’s kind of like a crossbow, where you can crank the bow multiple times to put energy into it. It’s far more than a single muscle could do.”</p><p>This web-based technique also make spiders the only known animals other than humans to store and release large amounts of energy through an external “tool” that’s not part of their own anatomy, says <a href="https://eeb.utk.edu/people/angela-chuang/">Angela Chuang</a>, an entomologist and spider expert at the University of Tennessee Knoxville who was not involved in the study. “[It] highlights how much we still don&#x27;t know about nature.”</p><p>What’s more, it seems that triangle weaver spiders aren’t alone in this ingenious act. At Georgia Tech, Alexander is currently studying a similar phenomenon in a Peruvian spider, which can zoom forward with an acceleration of up to 2,500 miles per hour per second. While both types of spiders can lasso lunch from a distance, Alexander’s spider builds three-dimensional, cone-shaped webs, and releases them even before insects have made contact with the silk.</p><p>This trigger-happy tactic might be a bit riskier than waiting for a fly to blunder into an actual web, Alexander says, but it also means less waiting around. Either way, both methods alleviate the need for the arduous and perhaps perilous task of rushing headlong into the path of an infuriated insect. “This completely changes the game of hunting,” Alexander says. “Now you’re less tired because the web is doing the work.”</p>
            <figure class="richtext-image full-width"><img alt="200443.jpg" class="richtext-image full-width" height="533" width="800"
            src="/wgbh/nova/media/images/200443.width-800.jpg"/><figcaption><p><i>Hyptiotes cavatus</i> holding its web in tension. On the left is the anchor line that secures the spider to a branch. On the right is trap line connected to main web, keeping it taut. Image Credit: Sarah Han, Todd Blackledge Lab, University of Akron</p><div class="credit"><p></p></div></figcaption>
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            <p>The technique could even have the added benefit of helping spiders avoid their own predators, allowing them to springboard away from an oncoming attack, says study author <a href="https://www.uakron.edu/biology/faculty-staff/detail.dot?u=tab27">Todd Blackledge</a>, an entomologist at the University of Akron who oversees Han’s work.</p><p>But, of course, there’s no such thing as a free lunch, even for spiders. The biggest downside of this behavior is that “the web basically gets used up in a single prey capture event,” forcing the spider to reconstruct in advance of every meal, Blackledge says. “That’s potentially a real cost.”</p><p>As for the possibility of humans invoking the wrath of slingshotting spiders, Han isn’t terribly concerned. “There’s a pretty low chance you’d run into these spiders,” she says. “They’re super tiny and they live in woodsy areas.”</p><p>Even if you do chance upon a hungry <i>Hyptiotes</i> on a day hike, Han says, it won’t be terribly interested in catapulting into <i>you.</i> This sneaky spider has its sights set on a far smaller prize—an unfortunate insect who, if all goes as planned, won’t even see it coming.</p></div>
  

  
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<p>Using its web as a “tool” to store and release energy, the triangle weaver spider lunges at speeds equivalent to a human sprinting at 1,700 miles per hour.</p>

Topic: Nature

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