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Sixty-six million years ago, an asteroid wiped out the dinosaurs in a fiery global catastrophe. But we know little about how their successors, the mammals, recovered and took over the world. Now, hidden inside ordinary-looking rocks, an astonishing trove of fossils reveals a dramatic new picture of how rat-sized creatures ballooned in size and began to evolve into the vast array of species—from cheetahs to bats to whales to humans—that rule our planet today.

Amazing fossils reveal how mammals took over after an asteroid wiped out the dinosaurs.

Rise of the Mammals

From singing whales and squeaking bats to thumping spiders and clicking dolphins, the world is filled with the exotic sounds of our fellow creatures. What are they saying? While we believe language sets us apart, some animals demonstrate they can learn our language—like Chaser the dog, who recognizes hundreds of words, and Kanzi the bonobo, who appears to have a sophisticated understanding of spoken English. But can we decode their own communications? NOVA Wonders follows researchers around the globe who are deciphering an amazing array of clues that reveal how animals share information critical to their survival. Will we one day be able to write the bat dictionary or decode the hidden sign language of chimps? And what can these findings tell us about the roots of our own language?

Can we crack the code of animal communication?

What Are Animals Saying?

(This program is no longer available for online streaming.) A seven-mile-wide asteroid collided with Earth 66 million years ago, triggering a chain of events that coincide with the end of the dinosaurs. But experts have long debated exactly what happened when the asteroid struck and how the giant beasts met their end. Now, scientists have uncovered compelling new clues about the catastrophe—from New Jersey to the wilds of Patagonia—and an international expedition of scientists has drilled into the impact crater off the coast of Mexico, recovering crucial direct evidence of the searing energy and giant tsunami unleashed by the asteroid. Join NOVA as scientists piece together a chillingly precise unfolding of the Earth’s biggest cataclysm, moment by moment, and discover how our early mammalian ancestors managed to survive and repopulate the Earth. (Premiered December 27, 2017)

Experts drill into the impact crater of an asteroid that created a worldwide cataclysm.

Day the Dinosaurs Died

Koch Foundation

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6 stinking cool facts about dog noses

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Did you know that dogs can use their cold, wet (and cute!) noses to sense sources of heat and thermal radiation? That discovery, via a <a href="https://www.science.org/content/article/new-sense-discovered-dog-noses-ability-detect-heat">2020 study from Sweden</a> that challenged dogs to choose between a warm and cool object across a room, makes them only the second mammal known to possess that superpower. (The other is a vampire bat.)And that’s not all dogs' noses can do. Read on for six reasons why dog noses are among nature’s most amazingly engineered instruments—instruments whose power humans are <a href="https://www.pbs.org/wgbh/nova/video/electronic-nose-imitate-dog-nose/">now trying to recreate</a>: 1. Dogs' <a href="https://www.pbs.org/wgbh/nova/article/dogs-sense-of-smell/">sense of smell</a> is between 10,000 and 100,000 times as potent as humans’. This power comes in part from the up to 300 million olfactory receptors dogs carry around in their noses, compared to our mere 6 million. And the part of the canine brain that is dedicated to smells is 40 times larger than ours, proportionally speaking. 2. Dogs can smell continuously, even while they’re breathing in and out. In contrast, when a human smells a scent (sniffs a rose, for example) we inhale that odor and breathe in oxygen through the same passage. But if a dog smells the same flower, air “splits into two different flow paths, one for olfaction and one for respiration," Brent Craven, a Pennsylvania State University bioengineer who has modeled <a href="https://anatomypubs.onlinelibrary.wiley.com/doi/full/10.1002/ar.20592">canine olfaction anatomy</a> using high-resolution MRIs, <a href="https://www.pbs.org/wgbh/nova/article/dogs-sense-of-smell/">told NOVA</a>.Craven and his colleagues found that a portion of the air dogs inhale gets ushered into a specialized area at the back of the canine nose reserved for odor detection, while the rest of it continues rushing toward the lungs. And when dogs exhale, that air departs through nose slits in a unique aerodynamic pattern that also guides new air in, creating a cycle of breath that continuously supplies the in-house laboratory in the back of the canine nose with new material. In <a href="https://pubmed.ncbi.nlm.nih.gov/8735662/">one study from the University of Oslo</a>, a dog on a hunt sniffed continuously for a full 40 seconds, across 30 respiratory cycles!<h4>Watch: This Device Smells Diseases by Imitating a Dog's Nose</h4>
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3. Dogs can <a href="https://vcahospitals.com/know-your-pet/how-dogs-use-smell-to-perceive-the-world">wiggle their nostrils independently</a>, which helps them figure out which direction a scent is coming from. Humans can only wiggle their nostrils simultaneously. (Try it. We’ll wait.)4. Dogs are great at interpreting all the information coming in through their noses in fine detail. In her book “Inside of a Dog,” canine cognition researcher Alexandra Horowitz writes that humans might taste a teaspoon of sugar added to a cup of coffee. But a dog could detect the same teaspoon of sugar in a million gallons of water—enough to fill two Olympic-sized pools.And to take the sugar metaphor further, “if we humans walk into a bakery, we can say, ‘someone’s baking a pie in here,’” canine search specialist Lynne Engelbert <a href="https://www.pbs.org/wgbh/nova/article/cremation-ashes-sniffing-dogs-california-wildfire/">told NOVA</a>. “A dog would walk in and say, ‘Oh, someone’s baking a pie in here, and it has apples, and butter, and cinnamon, and nutmeg.”
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5. Dogs can connect a human with the scent they leave behind with exceptional precision—and even help diagnose sick humans with a variety of diseases. Forensic chemist Ken Furton, who has studied dog olfaction for more than 25 years, once blew up a car with colleagues and then asked detection dogs to pick out human scent from the resulting debris. The dogs were able to sniff the small amount of shrapnel and correctly identify the people who had been in contact with the bomb pre-explosion 82% of the time.More recently, Furton and his colleagues looked at whether dogs might be trained to identify COVID-19 patients—and found they could do so with 97.5% accuracy. “I was shocked,” he told NOVA. And <a href="https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.2019.33.1_supplement.635.10">one 2019 study</a> indicated humans’ best friends can sniff out cancer with a similarly high 97% accuracy rate.<h4>Watch: Cannabis-Sniffing K-9's: Out of a Job?</h4>
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 6. Dogs can not only identify human remains–they can sniff out already cremated remains from among other ashes. Dogs in the American West are now being trained to <a href="https://www.pbs.org/wgbh/nova/article/cremation-ashes-sniffing-dogs-california-wildfire/">look for the cremated remains</a> of homeowners’ loved ones when those homes are lost to the region's increasingly fierce wildfires. The non-profit Alta Heritage Foundation brings specially trained search dogs and archaeologists to the site of a house destroyed by fire, using canine colleagues to narrow down where the lost ashes might be buried and then archeological techniques to excavate them. The ashes are often the only thing his clients want to recover from their houses, Alta Heritage founder Alex DeGeorgey told NOVA. So being able to find their loved ones’ ashes within the ashes of a house is both powerful and continually surprising. “I’ve done this hundreds of times,” DeGeorgey says of cremation ash recovery, “and I still marvel that we’re able to do it.”
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Dogs can sniff out disease and analyze new odors even as they exhale. But how?

Legal Hemp vs. Illegal Cannabis

To qualify by law in Nebraska as hemp, a cannabis plant must contain less than 0.3% THC, the main psychoactive substance in cannabis. Exceeding 0.3% THC in hemp can result in the destruction of an entire harvest in Nebraska and other states with similar laws. See what farmers and producers of hemp products in Nebraska need to do in order to not cross the line from legal hemp to illegal cannabis.
To qualify by law in Nebraska as hemp, a cannabis plant must contain less than 0.3% THC, the main psychoactive substance in cannabis. This level is low enough to not cause intoxication. Exceeding 0.3% THC in hemp can result in the destruction of an entire harvest in Nebraska and other states with similar laws.THC is just one of many cannabinoids, the compounds in cannabis that interact with specialized receptors in our brains and bodies, which the plants naturally create. THC content can rise or fall at any stage of breeding, growing or processing and can get to concentrations up to 30%—100 times the amount to be classified as hemp.Sweetwater Hemp, in Pleasanton, Nebraska, began processing hemp in 2020. The company purchases the plant and extracts cannabidiol or CBD, another of the many cannabinoids found in cannabis. Unlike THC, the psychoactive CBD does not produce a high. Two weeks before Sweetwater’s anticipated harvest, state regulators are called to take random samples of the crop, which are sent to an independent lab. (Nebraska-based Kennebec Analytical Services is one of the first in the state to get the needed certifications to test cannabis.) The final report provides measurements of multiple cannabinoids and, most importantly, determines whether the THC falls within the 0.3% legal limit to classify the product as hemp. If there is too much THC, the law demands every single plant in the batch be destroyed.The next step is turning the acquired plants into product. Even if the crop hits the legal THC mark, the same rules apply to what’s extracted from the hemp. The part of the cannabis plant with CBD gets hand-stripped from the rest of the plant, soaked in ice water and filtered. After being filtered three times, the mixture comes out as bubble hash and is blended with a concentrated version of coconut oil, which becomes the base ingredient of CBD-based products on the market. Some industry players and consumers think cannabis compounds, like THC, help boost the medicinal qualities of CBD, which is why the producers try to get as close to the legal limit as possible. But more data is needed on the how much THC helps with the medicinal qualities of cannabis, scientists say.This video was produced in collaboration with NOVA and is made possible in part by the Corporation for Public Broadcasting, a private corporation funded by the American people.
Legal Hemp vs. Illegal CannabisPublished: March 31, 2022NARRATOR: These plants are cannabis and they might be illegal in Nebraska, or they might be legal. This cannabis is classified as hemp, and it&#x27;s legal here. By law to qualify as hemp, a plant must contain less than 0.3% THC, the main psychoactive substance in cannabis, a level so low, it&#x27;s not known to be intoxicating. That means in states like Nebraska, exceeding the narrow threshold for THC in hemp can result in a loss of an entire harvest.AMANADA McKINNEY (Medical Doctor, Doane University Faculty, A&amp;A Apothecary Partner): We have to find some way to prevent entire crops from being destroyed, if they&#x27;re just above that, that, that illegal limit, right? That 0.3%.NARRATOR: THC content can rise or fall at any stage of breeding, growing or processing.ANDREA HOLMES (Organic Chemist, Doane University Faculty, A&amp;A Apothecary Owner): Hemp is kind of like a little baby. You don&#x27;t, they don&#x27;t, it doesn&#x27;t always do what you want it to do. So sometimes depending on temperature and climate conditions, the controlling the cannabinoid levels can be difficult. So it&#x27;s, it&#x27;s not easy.NARRATOR: Cannabinoids are the compounds in cannabis that interact with specialized receptors in our brains and bodies. THC is just one of the ingredients that the plant can produce, sometimes up to levels of about 25 to 30%.RORY CRUISE (Sweetwater Hemp CEO): And we&#x27;re down here trying to deal with 0.3% THC. So there&#x27;s a huge difference.NARRATOR: Sweetwater Hemp began processing hemp in 2020. The company purchases the plant and extracts cannabidiol or CBD another cannabinoid from the plant. But unlike THC, it does not produce a high. They&#x27;ve cultivated a couple of research crops in their greenhouses. Growers use genetics to engineer plants that repress their own THC content.RORY CRUISE: They keep being able to find that genetic, create that, that cannabinoid and have that type of plant that creates that specific cannabinoid.NARRATOR: Where the hemp is planted may cause drastic swings in the THC level. Sweetwater recognized its research crop in one of its greenhouses produced high quality plants that push the boundaries on THC content.RORY CRUISE: Those plants, they have the best of both worlds of not dealing with high extremes outside of wind and conditions and, and and those kinds of things. And they just really push and thrive really fast.NARRATOR: Two weeks before Sweetwater&#x27;s anticipated harvest, state regulators are called to take random samples of the crop. The plants are sent to an independent lab. Nebraska-based Kennebec is one of the first in the state to get the needed certifications.CONCETTA DiRUSSO (Kennebec Analytical CEO, University of Nebraska- Lincoln Biochemistry Faculty): We take the sample, we grind it. We sieve it to get the seeds and the stems out. We grind it again to make a very, very fine powder. And then using organic solvents, we extract the cannabinoids.NARRATOR: The final report provides measurements of a whole range of cannabinoids. And most importantly determines whether the THC falls within the 0.3% legal limit.CONCETTA DiRUSSO: I think it&#x27;s, what&#x27;s, what&#x27;s challenging for us, and we keep it always at the forefront, is how important and serious this measurement is. That it means the difference between harvesting and marketing a field of hemp, a greenhouse of hemp, or destroying your crops.NARRATOR: If there is too much THC, the law demands every single plant in the batch be destroyed.Those black buckets are all that remains of a recent Sweetwater hemp crop that tested over 0.3.RORY CRUISE: I was 0.39 on my very first one and 10 days before that I was 0.26.NARRATOR: The team considers it to be part of the learning curve.BRETT MAYO (Sweetwater Hemp Chief Marketing/Extraction Officer): The first time you grew corn, was it perfect? No. The first time you grow soybeans, was it perfect? No.NARRATOR: Next step, turning the acquired plants into product. Even if the crop hits that legal THC mark, the same rules apply to what&#x27;s extracted from the hemp. The flower gets hand stripped off the buds, which are soaked in ice water and filtered.BRETT MAYO: And it then goes through 1, 2, 3, 3 filters before it comes out as bubble hash.NARRATOR: The bubble hash is blended with a concentrated version of coconut oil, which becomes the base ingredients for the dozens of CBD-based products on the market.BRETT MAYO: And the hard part about that is you want to be as close to that 0.3 as possible because THC kind of has a bad reputation. But THC is going to help that product to be better.NARRATOR: Some industry players and consumers think cannabis compounds like THC help boost the medicinal qualities of CBD, but scientists say we need more data.There&#x27;s one other way hemp growers could stay out of trouble; change the federal law and increase the amount of THC allowed.AMANADA McKINNEY: And I think raising the threshold on that would help, especially Nebraska farmers, with growing industrial hemp. So they don&#x27;t have to be so diligent about catching that plant before it&#x27;s gone over that limit.NARRATOR: Whether the law changes or not, those processing and marketing hemp see the crop has its own distinct place in the market. Even in places where cannabis with higher levels of THC remains illegal.CONCETTA DiRUSSO: Oh, it&#x27;s amazing. And I really look forward to how it&#x27;s going to change. I think that these plants have so much to offer in terms of medicinal properties and other things. There&#x27;s a lot of good that comes out of this plant.

To qualify by law in Nebraska as hemp, a cannabis plant must contain less than 0.3% THC, the main psychoactive substance in cannabis. Exceeding 0.3% THC in hemp can result in the destruction of an entire harvest in Nebraska and other states with similar laws. See what farmers and producers of hemp products in Nebraska need to do in order to not cross the line from legal hemp to illegal cannabis.

Animal Care Supervisor Lisa Dijenno bottle-feeds a manatee named Tober. Image courtesy of ZooTampa

A day at a Florida manatee hospital

On December 7, 2021, NOVA Digital Editor Alissa Greenberg visited ZooTampa’s David A. Straz, Jr. Manatee Critical Care Center to see up close how rescued manatees are recovering and regaining strength amid an ecological crisis and widespread starvation.10:15 a.m. It’s feeding time at the manatee critical care center at ZooTampa, and the calves are ready and waiting. Even before the staff brings bottles of thick formula over to the pool where they are swimming, four sets of fuzzy nostrils break the surface, whiskers wiggling. “As you can see, they know it’s time,” says Animal Care Associate Kelcey Innes. The calves, which are all smaller than a duffel bag but may someday weigh close to 1,000 pounds, suck down the formula, then chew on the bottles’ rubber nipples playfully. 
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There will be more food soon enough—calves at the center are fed every four hours around the clock. But for now, Innes and coworker Sabrina Sauseda have a different task: watch for manatee farts, proof of digestive systems in working order. After a few minutes, Sauseda spots telltale bubbles. “Calliope had gas!” she announces.The center keeps up this intensive feeding schedule because if the calves were still nursing with their mothers, they would be gaining at least a pound a day. But these calves are orphans, part of an ongoing manatee crisis in Florida. Manatees are in trouble all over the state—particularly on its Atlantic (east) coast, they are starving. Last year was the <a href="https://www.tampabay.com/news/environment/2022/01/10/a-record-1101-florida-manatees-died-in-2021-when-will-it-end/">deadliest on record</a>, with more than 1,100 manatees dead, close to 15% of the state’s population. The reason is seagrass: The Florida coast is home to what were once two of the largest undersea meadows in North America, and the plant makes up much of the manatee diet. But <a href="https://news.mongabay.com/2021/09/manatee-deaths-in-florida-point-to-a-global-decline-in-seagrass-ecosystems/">Florida's seagrass</a> ecosystems are collapsing, due largely to fertilizer and development runoff. In the Indian River Lagoon, once one of the continent's most productive estuaries, seagrass has declined an estimated 95% in the last 10 years.As one of four manatee critical care centers in the country, ZooTampa is caring for 23 <a href="https://www.mmc.gov/priority-topics/species-of-concern/florida-manatee/">manatees</a> on this December morning, double its historic capacity. A mother manatee may feed her calf until she starves, so the facility has also taken on an unprecedented number of calves in the past year, left alone after their parents perished. As their state attempts to clean up its waterways, the staff at ZooTampa are working overtime to save the animals that mean so much to the soul of Florida.
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<figcaption>Animal Care Professional Sabrina Sauseda bottle-feeds orphaned mantee calves at ZooTampa. Image courtesy of ZooTampa
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10:35 a.m. It’s also time for morning tube feeding. Two new residents have arrived within the last week, along with the early winter chill. Both were suffering from cold stress; one had a fresh boat propeller injury across his face. And they both need to eat while they convalesce.When a new manatee comes to the center after rescue by the Department of Fish and Wildlife, Animal Care Supervisor Jaime Vaccaro and her staff check its blood levels, respiration, and measurements. Then they set the new resident up in one of three medical pools that make up the hospital’s intensive care area. Each of these interconnected pools is equipped with its own heater, a vertical gate that can be lowered to cut off access, and a hydraulic floor that can be raised and lowered. This feature allows the staff to both customize the environment and raise the manatees out of the water for medical care.Last week’s adult arrival, Corduroy, is in too much distress to eat. After they use the hydraulics to lift him out of the pool, Vaccaro and Innes take some of Corduroy’s blood, then gingerly thread a length of plastic tubing down his throat. His tail flaps a little, but he calms and accepts the liquid quietly. Manatees’ complicated digestive systems are especially sensitive, so the staff tube-feed Corduroy multiple times a day to make sure he stays hydrated and maintains his weight until he’s ready to eat on his own—a process that could take months. Manatee digestion is “like the engine of a car,” Vaccaro says. “If they've been sitting for a while, they might not start back up right away.” Director of Conservation, Research, and Behavior Tiffany Burns connects the increasing number of manatee patients with Florida’s persistent water quality problems. “They look big and full of blubber, but they’re very muscular,” she says. “A lot of that body is intestines.” Without much insulation, manatees are very sensitive to temperature. If they swim in too-cold water long enough (anything under 68 F) they develop cold stress, which manifests outwardly in a frostbite-like icing of white, peeling tissue visible on the flippers and muzzles of many of the animals here. And if they stay even longer, they may develop pneumonia, hypothermia, and organ failure. Manatees typically migrate to warmer water during winter months, but those areas that could once support many manatees in a cold snap no longer have enough seagrass to feed them.
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<img alt="Manatee lies on plank floor and a person holds a tube near his face for feeding" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/tube-feeding_Corduroy.width-990_OFyYUuH.jpg"/>
<figcaption>Newly arrived adult manatee Corduroy is tube-fed at ZooTampa. Image courtesy of ZooTampa
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10:45 a.m. It’s feeding time (again) for the general manatee population housed at the front of the center in two broad pools backed by fake rock walls frequented by very real snowy egrets and great blue herons. Here, meals start at 7:30 a.m. and snacking continues almost without pause all day.On the path between the pools, Intern Olivia Callitsis is unloading heads of endive, escarole, and romaine lettuce from a pallet and stuffing them into a length of PVC pipe with a long hole in the side, so the greens spill out like a planter. A manatee consumes 10%-15% of its body weight daily, and occupants of the two main pools eat through some 1,200 pounds of produce a day. That makes the manatees the most expensive animals to feed at the zoo, costing some $40,000 a month. Burns says the money mostly comes from gate fees and private donors.With a gentle push, Callitsis launches the pipe into the pool, where it bobs gently before sinking. “You can throw it on the surface,” she says of the lettuce, “but this really mimics the natural environment. They have to dive down, work for it a little.” Soon, the surface is broken here and there by smooth gray backs and broad tails, then wrinkly, whiskery snouts munching intently.The inhabitants of the general population pools are mostly at the end of their stay here, with durations that average five months for adults and two years for calves. Because the goal is release, Vaccaro and her colleagues do not engage in the typical zoo enrichment activities, instead switching the manatees between pools frequently so they don’t get too used to their surroundings. And as soon as the calves are stable enough, Vaccaro buddies them up so they learn natural behaviors.
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<figcaption>Animal Care Professional Leesa Whittlef places a feeder full of lettuce into a critical-care manatee pool at ZooTampa. Image courtesy of ZooTampa
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2:00 p.m. It’s time for the second bottle feeding of the day. Innes and Sauseda carry bottles with a mix of vitamins, baby formula and oils like red palm fruit and macadamia to the medical pools. They lean over and slap the surface to get the calves’ attention and let them know where the goodies are. Small snouts appear and latch onto the bottles, clouds of formula spreading in the water.Burns is aware of the appeal of manatee calves in particular. “Everybody loves manatees and wants to help,” she says of the zoo’s visitors, but they don’t always connect their decisions at home with the fate of the animals they love. “Everyone wants that big, beautiful green lawn, perfectly manicured. But it comes at a cost.”She’s referring to the role nitrates from fertilizers play in <a href="https://www.pbs.org/wgbh/nova/article/florida-red-tide-gulf-coast/">fueling algae blooms</a>, which can block out the sunlight seagrass needs to survive. Similarly, pollution from agricultural runoff, construction, and sewer outflow can cloud coastal waters, starving out seagrass. Sick and dying grass can no longer stabilize the sea floor, which means even more sediment floats up into the water—compounding the situation and giving algae the upper hand, says Lead Biologist Ryan Brushwood of aquatic restoration company Sea &amp; Shoreline. What started as a little algae quickly grows, and ultimately the system hits an inflection point.  
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Some 70 miles north of Tampa, the community of Crystal River saw exactly what that looks like when, in the 1990s, an area that had once hosted some of the state’s largest seagrass meadows was overcome by muck and an algae called Lyngbya wollei. “There was no grass whatsoever,” remembers Lisa Moore, president of the non-profit Save Crystal River. “There were huge plumes of algae growing everywhere.” The water stank; dogs that swam in it got sick. And the population of manatees that had long flocked to the area for its warm springs found little food. In 2015, Save Crystal River hired Sea &amp; Shoreline for a multiyear project: sucking up millions of pounds of muck and water and treating it with a polymer that binds with particles suspended in the water so they become heavier and settle out. The leftover muck is taken to farms to use as fertilizer. Then, Brushwood and his colleagues plant new grass, which they keep in underwater cages to protect it from nibbling manatees until it is well established.Since the plant grows in rhizomes, underground shoots that extend long lateral stems in all directions, it can cover a lot of ground quickly. So far, Save Crystal River has replanted 300,000 plants covering 54 acres out of a planned 92—and those 54 acres have naturally expanded to over 200. The water is clearer, fish and crabs have returned—and so have manatees, in abundance. Save Crystal River hopes its model can be repeated elsewhere in Florida, perhaps including the Indian River Lagoon.  
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<figcaption>Jaime Vaccaro and Sabrina Sauseda tube-feed manatee Kristoff, who has been lifted out of a medical pool with a hydrulic floor for feeding. Image courtesy of ZooTampa
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3:15 p.m. Vaccaro begins shifting manatees around in the medical pools, opening and closing the vertical gates to make space for Pebbles, a mostly-recovered adult who’s been at the center for close to a year. She was in critical condition when she was rescued, with cold stress and propeller wounds that weren’t healing. But she’s made a remarkable recovery and moved into the general population pool not long ago.Pebbles’ bloodwork has recently shown that she might have a brewing infection, though, so she’s receiving antibiotic injections. But after a few days of shots around the same time, Pebbles has figured out the pattern. Vaccaro slips into the water to try to isolate her into medical pool 3 but, in a flash, Pebbles breaks free, using the full force of her tail to twist through the open gate and into the shallow canal that connects the medical and general population pools. Vaccaro radios for help. “She knows she’s going to get an injection, and no one likes those,” Innes says. Instead, Pebbles plays a watery game of cat and mouse. Whenever Vaccaro moves toward her, she glides powerfully to the other side.After half an hour, the staff is on the verge of giving up, aware that Pebbles is stronger than they are. “We try not to force them to do anything they don’t want to do,” Innes says. “But these treatments save their lives, so we have to find that line of when to intervene.”4:25 p.m. As the winter sun starts to dip lower, Vaccaro prepares for the night, loading up PVC pipes full of lettuce and letting whole escarole heads thwap on the surface of medical pool 3 until it’s silty and bobbing with leaves. The buffet of greenery is enough to keep several hungry manatees fed into the wee hours, she reasons—plus, it might tempt Pebbles back into the pool on her own.4:30 p.m. To Vaccaro’s surprise, the tactic works. She moves quickly to drop the gate and hem Pebbles inside. 4:40 p.m. With the floor of medical pool 3 raised all the way up, the heads of lettuce are suddenly beached—and so is Pebbles. Vaccaro and a colleague cover her with a heavy mat, at times using their bodies to keep her steady. The first needle breaks, and Pebbles squirms away, but a second attempt to inject her succeeds. Vaccaro heaves a sigh of relief as Pebbles is lowered back into the pool.
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<img alt="A team loads a large blue sling containing a manatee into a truck" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/Loading_Chandler_for_release.width-990_NYhrGgJ.jpg"/>
<figcaption>A manatee named Chandler is loaded for release into the wild in January 2022. Chandler spent a year at ZooTampa's manatee critical care center after being brought in as a juvenile suffering from cold stress. Image courtesy of ZooTampa.
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4:55 p.m. The zoo is closing, but the center’s day never really ends. Vaccaro moves from her antibiotic triumph to mixing up formula for the calves in a cramped office behind the pools, then uses the waning light to tube-feed all three adult manatees in the medical pools in quick succession.When it’s recovering adult Flapjack’s turn, he lies quietly as the slurry of romaine lettuce and formula slips down his throat. He’s gained 70 pounds since he arrived, Sauseda says, showing a photo from the day he arrived with ribs protruding and belly sunken. The difference is still obvious between Flapjack and the other manatees, especially in the definition of his head and the slightness of his torso. But when Vaccaro and Sauseda finish feeding him, his eyes look somehow brighter.Florida made headlines this winter when it went ahead with a controversial program to <a href="https://www.palmbeachpost.com/story/weather/2021/12/08/fwc-oversee-feeding-plan-manatees-starving-death/8887866002/">feed wild manatees</a> in the Indian River Lagoon, in part with the hope of <a href="https://www.mysuncoast.com/2022/03/24/officials-florida-manatees-eat-every-scrap-food-trial/">helping individuals</a> like Flapjack so they don’t need to be treated at places like the center. In Burns’ mind, the most urgent question is how to stop the same thing that’s happened on the state’s Atlantic coast from repeating around Tampa, on the Gulf side. “Let’s learn from this,” she says. “We don’t want to wait for another largest death toll in a year. Let’s get ahead of it and make sure our animals have clean water.” State funds made available for water cleanup are a start, and education is a big part of any solution, she says. But such an urgent and entrenched problem needs a multipronged approach. “You can’t rely solely on education, on rehab, on laws—people break laws all the time. People have to work together in multiple ways to try to solve these problems.”As Flapjack returns to the water, Vaccaro pauses to make sure all her charges are breathing and swimming well after their feeding. She’s also made sure that every manatee has appropriate company overnight—no “busybody” animals that will annoy their poolmates, no males and females that might cause trouble together. Then she walks back to the office for final evening preparations and, eventually, to head home. The center finally lies calm in the half-dark, silent but for the lap of water and occasional hiss of a manatee’s breath. But someone will be back at 10 p.m to feed the calves.
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As Florida’s seagrass beds die off, manatees are starving. Can the seagrass–and the manatees–make a comeback?

Why Wombats Poop Cubes

Biologists and engineers solve a major marsupial mystery.
Scientists solve a mammal poop mystery: Why do wombats have cube-shaped feces?
Why Wombats Poop CubesPublished: March 23, 2022NARRATOR: Introducing the cube, the only six sided scat in nature an exceptional excrement direct ♪ ♪ from the bottom of the common wombat. Wombats are Australian marsupials. They graze continuously. It can take up to two weeks for them to digest their food. The process squeezes out every last drop of water. A good strategy in Australia&#x27;s harsh climate but that doesn&#x27;t explain how or why the end result is a cube.PATRICIA YANG: From, from my eyes, it looks very artificial. Like is that even a real thing comes out from animal body? For most mammals, including humans, the feces come out like a toothpaste coming out. So when you squeeze it, the shape of feces the same as the the orifice and the solid soft matter comes out slowly and but smoothly as a sausage. But how would wombat has this cubicle shape? Our hypothesis is that it must be the intestine that molded this shape.SCOTT BURNETT: The logical next thing to do for us was to examine microscopically what the tissues looked like. We found thicker and thinner muscle around that circumference. And along the length of the intestine these sort of thicker and thinner regions formed bands.PATRICIA YANG: We have never seen this before in any kind of animals. We are wondering if different thickness, the thicker and thinner bands how would that affect the stretchiness of the wombat intestine? So we put a wombat intestine into this Tensile Test. Tensile test is the way to test how stretchy this material is. And we discovered that the lumping test is stretch but they are not stretch in an even way. For the thicker part they stressed less than the soft part. We were surprised that the stretchiness were four times different among those two bands. With this measurement, we fit in this information to a mathematical model and that it contracts and over several cycles contraction we see a shape with four corners.SCOTT BURNETT: I&#x27;ve got a really simple way of showing pretty much how they form these cubes using this rubber here. And so we can just kind of pinch the sides of the rubber band and kind of simulate those, those more stiff regions of the intestine. And if you just hold it like this you can just give a go like that, and it begins to form a cube. So when the contractions happen it is basically squeezing the feces into this shape and it does this rhythmically over time. And so they eventually get molded into that. And as the moisture is absorbed out of the feces and it starts to fragment along its length and form the distinctive actual cubes that come out at the end.

Biologists and engineers solve a major marsupial mystery.

An Australian magpie. Image Credit: NAPARAZZI, Flickr

How magpies outwitted researchers in Australia

When Dominique Potvin and her team set out to test a new technology for tracking birds, they didn’t think they were entering into an interspecies game of one-upmanship. Instead, Potvin, an animal ecologist at the University of the Sunshine Coast in Australia, was hoping to both track the animals’ movements and solve a persistent issue in the study of birds. Approximately 70% are too small to be tracked using a traditional battery-powered GPS tracker, since the weight of the devices can harm them. The new, harness-based trackers Potvin and her team had developed weighed only one gram, with a strap that could detach if the birds approached a specialized magnetic station. That would allow the researchers to collect the trackers without having to recapture the birds.“We wanted to see if the new design would work as planned, and discover what kind of data we could gather,” Potvin wrote in a recent piece <a href="https://theconversation.com/altruism-in-birds-magpies-have-outwitted-scientists-by-helping-each-other-remove-tracking-devices-175246">for The Conversation</a>. “How far did magpies go? Did they have patterns or schedules throughout the day in terms of movement, and socialising? How did age, sex or dominance rank affect their activities?” Australian magpies also seemed to her a prime species for testing new tracking technology because of their larger size. The accepted size of a tracker in ornithology is about 3%-5% of an animal’s body weight. These new trackers weighed about 1%. “We were excited by the design,” she wrote.
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But the magpies had other ideas. During the month that Potvin and her team spent fitting five magpies with trackers and watching their behavior, “we directly observed four actively removing the trackers,” they <a href="https://www.birdlife.org.au/afo/index.php/afo">wrote in a study</a> published last month in the journal Australian Field Ornithology. At first, the birds pecked at their own trackers—but then something more interesting happened. An adult female approached one of the juveniles fitted with a tracker and pecked at the device until it came apart and fell off. At the same time, elsewhere, another adult magpie also had its device destroyed by a companion. Soon, all the other trackers had been removed.The team wasn’t too concerned when the magpies started pecking at the harnesses, “but the more time went on and the more they worked on the harness, the more worried we became,” Potvin said by email. “As soon as that first tracker came off, we just looked at each other in disbelief: we knew it was all over!”She and her team were astonished. What, they wondered, could this unlikely outcome mean?Potvin and her team saw the magpies’ tiny mutiny as something more than a stunt. Australian birds have a reputation for being collaborative. The continent is the world capital for cooperative breeding, where birds help raise chicks of the same species that aren’t their own—a behavior Australian magpies engage in. They’re also known for working together to defend their territories.Since the magpies already have experience cooperating to solve problems, the authors argued, they might apply the same strategy to a new challenge. They interpreted the magpies’ removing each other’s trackers as altruistic behavior, or actions that only benefit another individual. The first magpie that destroyed another’s harness wasn’t wearing one itself, Potvin said over email, meaning that “the work was not going to be reciprocated.” She did note, however, that it’s possible the behavior might strengthen social relationships, creating long-term benefit. “These kinds of rewards are definitely plausible, but we have no way of knowing whether they played a part in this activity,” she wrote.In looking for an explanation, Potvin and her team first thought of allopreening, a behavior where birds clean each other—sometimes removing parasites—to strengthen their bonds. But that is “a very straightforward behaviour, and does not involve any kind of determination, persistence or problem solving,” she wrote, “it’s not really ‘targeted’ with a specific goal in mind.”Instead, they thought the most likely explanation was that the magpies were exhibiting “rescue behavior,” a very rare phenomenon in which one helper animal works to free a peer in distress, with no benefit to itself. Although the tracker was not dangerous, wearing it “may have felt a bit like being ‘tangled’” for the magpies, Potvin wrote, prompting other birds to respond.
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<img alt="Australian magpie on fence" class="richtext-image full-width" src="https://staging.pbs.org/wgbh/nova/media/images/27810942789_a3f5de916e_o.width-990_IUB30Xb.jpg"/>
<figcaption>An Australian magpie sits on a school gate post. Image Credit: birdsaspoetry, Flickr
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The removal of the trackers represented a series of puzzles “requiring cooperation (the bird with the tracker had to stand pretty still for the other bird to work on them!), some altruism, and some cognitive problem solving,” she added. Such rescue behavior has been observed in Seychelles warblers, which sometimes get sticky seeds caught in their feathers, but until now researchers haven’t documented it in other birds. “It is possible that what we have observed is the first documented case of rescue behaviour in Australian Magpies,” the team concluded in its study.Gisela Kaplan, a professor of animal behavior and zoologist at the University of New England in Australia who has studied Australian magpies for decades, agrees that pilot studies like Potvin’s are valuable for testing new technology on a small scale. But she emphasizes that the group of five magpies was likely a family, making the observations tantamount to one single anecdote. “I’ve seen lots of individual behaviors in magpies that I couldn’t explain,” Kaplan says—for example, she has written <a href="https://theconversation.com/magpies-can-form-friendships-with-people-heres-how-83950">for The Conversation</a> about a magpie in her yard who appeared to be gardening with her, and another instance in which one flew into her home and pecked at her keyboard after watching her type—“but I wouldn’t have written a paper about it.”Lisa Horn, a comparative behavior researcher in Vienna, Austria, who studies altruistic behavior, agrees—especially since the team didn’t set out to test that kind of behavior. “Coming from a tradition of cognitive biology, we’re very careful with our experimental design, to try to rule out any other explanations and carefully control the conditions,” she says. But that kind of design is impossible when the outcome is an accident.Kaplan suggests there are other possible explanations for the magpies’ digital striptease that could be just as interesting, including “play behavior, competitive behavior, all sorts of things.” Kaplan’s research has shown that juvenile magpies play quite a lot, including among themselves and with objects. “The object play that I’ve observed is always competitive,” she says, adding that many of those play interactions include stealing a desired item.
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Another possibility, Horn suggests, is simple distress. “A lot of songbirds, and also Australian magpies, have very close social bonds with their partner,” she says. “If something happens to my mate, and it freaks my mate out, that also freaks me out.” That leads to what Horn calls “emotional contagion,” and the desire on all sides to resolve the distressing situation. This is a much simpler mechanism that is found in a wider array of animals than generosity, empathy, or altruism, she says. The danger in such circumstances is anthropomorphism, ascribing human experiences to animals because that’s how we might behave or feel. “Especially in cognitive biology and behavioral biology, we are very careful with using these terms,” she says.But while Potvin agrees that being thoughtful about anthropomorphism is important, she feels it can sometimes be “helpful, or even somewhat accurate” to consider the parallels between human and animal behavior. “The risk comes when we think we know what the birds are actually thinking,” she said over email. For example, they don’t know how the birds viewed the trackers, nor their problem solving strategy for removing them. “But we do know what they did, and that in and of itself is pretty impressive.”Both Horn and Kaplan agree that the idea that the magpies may exhibit rescue behavior is plausible. After all, the birds are remarkably cooperative in other ways. Plus, similarly empathetic “consoling” behavior has been observed a few times in ravens. And in Horn’s own research, she found that certain crows and magpies (though not the kind in Potvin’s study) were particularly likely to help others. Since both of the species <a href="https://elifesciences.org/articles/58139">in Horn’s research</a> were also cooperative breeders, she hypothesizes that having “such a family system—parents but also maybe aunts, uncles, someone else helping—seems to have led to a lot of this prosocial behavior in other areas.”But, Kaplan says, jumping right to rescue is a big deal because it implies empathy, or even “theory of mind,” the ability to imagine an experience different than one’s own—which all but the most intelligent animals lack. And even if it turns out that magpies do have theory of mind, that’s a separate thing from saying “I care,” Horn adds.Still, Potvin feels it’s not such an enormous leap, given that magpies’ cognitive abilities and complex social relationships are well established. Since the publication of her study, many readers have reached out to her to describe instances they’ve seen of similar behavior that appears altruistic or “rescue-like.” Could that suggest the behavior may be more common than previously thought? “I think that many people who watch and study birds have seen similar behaviours,” she wrote by email, “and thus the evidence is there for them.”Kaplan hopes that Potvin and her team (or someone else in the avian cognition community) will use these observations as a jumping off point, carefully designing an experiment to test their rescue behavior hypothesis —perhaps a study to see if Australian magpies would work together to get food or would help a peer weighed down with some burden or restriction similar to the trackers. The study makes a great starting point, she says: Accidental observations are “often how further experiments start.” She points to Alexander Fleming’s discovery of Penicillin on a moldy dish. “The important point was that he didn’t expect that result but was in the right place at the right time and had the training to pursue this in a scientific manner,” she says. Someone else might have spotted the mold and thrown the whole thing away. “But he didn’t. He thought it was a significant event.”
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During a recent study, a group of magpies removed their GPS trackers, astounding their observers. But were the birds actually trying to help each other?

Can Poop Help Protect Rhinos from Poachers?

To “scatologists,” a pile of fresh scat in the wild is a treasure trove of information.
The chemicals in rhinoceros feces help the animals communicate with one another. But to scientists and police, rhino scat tells a different story.
Can Poop Help Protect Rhinos from Poachers?Published: February 17, 2022SCOTT BURNETT: Look at the size of this scat, this is one that was dropped last night. It’s really fresh, sort of, beautiful stuff. If this had of come out of the bottom of my compost heap at home, I’d be really pleased with how well it’s gone. There’s all these really finely masticated and digested plant material, and just by coincidence, there’s a cow pat here, in front of the rhino heap, so you can really get a sense of how massive these animals are. And they’re just roaming in an out of the village here, and everyone seems to be getting along.Just imagine the size of the bum that this dropped out of. These are just a single scats. I’m after the motherlode.I’ve made a pair of tongs out of bamboo, to handle the scat hygienically, and there we go.Coming across fresh scat in the wild is a golden opportunity for a scatologist like me, even if it’s not for my research. Collecting samples for other scientists can help their studies. Some of this rhino poo may even be used to help save the greater one-horned rhinoceros.So, this large pile of scat, here, is a latrine site used by a few different rhinos. They communicate to the other animals in their population via the chemicals in their scats. They communicate social status and reproductive status and who’s in the neighborhood. It’s like a “fecesbook” for rhinos.But this social platform also attracts ruthless killers. A fresh poop pile is a message to poachers that rhinos visit here. They’re killed for their horns, which are smuggled out of the country and used for luxury goods or in traditional medicine, in parts of Asia.Scientists have figured out a way to protect the rhinos, by using their scat for forensics. They collect scat in the wild and extract D.N.A., which goes into a database. When a dead rhino is found, or a rhino horn confiscated from criminals, authorities can match its D.N.A. with D.N.A. in the database, to locate where it came from. The D.N.A. evidence can be used to convict poachers and to know where to concentrate police efforts.In the 1900s, they faced extinction; now there are over 2,600 greater one-horned rhinoceros in Assam.Perhaps this scat will go towards saving one more.Just using my G.P.S. here to get a geolocation for this sample.Latrines helps rhinos communicate, and now they may also help protect these superb pachyderms from extinction. That’s a good poop story.

To “scatologists,” a pile of fresh scat in the wild is a treasure trove of information.

How Did This Butterfly Get So Old?

A special diet could be the secret to its exceptional longevity.
While most butterflies feed on nectar only, this genus of butterfly also feeds on pollen.
How Did This Butterfly Get So Old?Published: February 3, 2022Narrator: Many butterflies live only for a few weeks, but one called Heliconius stands out with a lifespan closer to six months.Adriana Briscoe: One of the ways we think they can live so long is because they have changed their diet.Lawrence Gilbert: They live a long time because they have developed this ability to harvest pollen.Narrator: While most butterflies feed mainly on nectar, Heliconius adds pollen to its diet. The pollen sticks to the entire length of its proboscis. The pollen might keep the butterfly healthy, but Adriana has found a possible medical application derive from the way Heliconius digest the nutrient. She&#x27;s collaborating with chemist Rachel Martin.Briscoe: This is the part of the proboscis where fluids can go in and they can also go out.Rachel Martin: I was really fascinated to find out that it acts like a sponge. I was kind of always picturing this being like a giant drinking straw.Briscoe: Oh yeah, no. You can see that there are these ridges shown in green and those are perfect grooves for pollen to get stuck in, when the butterflies probe the flower and the pollen grains start to get stuck in those grooves. The butterflies then release saliva from the tip of their proboscis and that starts to glue things together.Martin: It makes sense that the butterfly would have enzymes that are really optimized for getting into those little nooks and crannies and digesting the protein because pollen is about 20% protein. So it is a lot.Narrator: The Heliconius&#x27; long life might be explained in part by this intake of high protein pollen, which it actually digests on the outside of its proboscis. Thanks to a very particular type of enzyme.Briscoe: That enzyme is known as cocoonase because it was originally discovered in silk moths. Silk moths have one version of this enzyme, which they use to digest their silk cocoons so they can escape. If that enzyme is not functioning, they die in their cocoons.Narrator: By extracting this cocoonase enzyme to reproduce its dissolving properties on a large scale, Adriana hopes to alleviate potentially serious medical conditions like blood clots.Briscoe: Blood clots are very common in the United States. It turns out you can take cocoonase and in a test tube, you can mix it up with a blood clot and it&#x27;ll break it down into its component parts.

A special diet could be the secret to its exceptional longevity.

Topic: Nature

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