On April 17th, 2018 we learned about

Mosquitoes let researchers indirectly monitor the movements of invasive pythons

Burmese pythons (Python bivittatus) often grow up to twelve-feet long, but they’re still surprisingly hard to find in the wild. This is bad enough for the prey these snakes want to ambush, but it’s created challenges for researchers tracking their activity as well, even in environments where these snakes aren’t supposed to live. Since the 1980s, failed pet-owners have been importing and releasing pythons in the Florida Everglades, harming the native wildlife in those swamps. Fortunately, one local species seems to be quite adept at locating pythons, which is why researchers are “recruiting” mosquitoes to help track the snakes.

Following snakes via swarming mosquitoes

Despite the mobility of an individual mosquito, they’re still easier to capture than a single Burmese python. The work starts with cardboard funnels and hand-held vacuum cleaners, but is then followed with DNA sequencing in the lab to see what species of animals the mosquitoes have been eating. When python DNA turns up, it lets researchers construct a map of where they’re moving, and possibly how they’re multiplying across the Florida swamps.

Since this work started in 2015, a few trends are already clear. Python populations have been growing, and expanding northward. At this point researchers don’t have a strict head-count on the snakes, but they know that there are enough to be making an impact on other species in the Everglades. Raccoons, for instance, have been getting eaten often enough that the turtle and alligator eggs they usually eat are hatching at unusually high rates.

Other types of tracking

If digging through mosquito stomachs seems too indirect, conservationists have a few other ways to follow invasive pythons. One option is to collect samples of dirt found near burrows, then dig through them for traces of python DNA. Each time a snake slithers by, it sheds a bit of DNA, eventually leaving enough to confirm activity in specific locations.

For something a bit more actionable, there’s the sentry snake program, conducted by the Conservancy of Southwest Florida. Male pythons are outfitted with radio trackers, then released back into the wild where they’ll hopefully find a mate, and possibly some friends. Once contact seems to be made, conservationists can raid the “aggregation” of snakes, capturing other males and any fertile female snakes that were fertilizing eggs. This method is rather labor intensive, but it has led to the removal of over 3,000 fertilized eggs from the Florida swamps before they had a chance to hatch.

Source: A UF researcher is tracking snakes using mosquitoes by Wyatt Schreiber, The Alligator

On April 15th, 2018 we learned about

Beyond bugs, mammals, birds and reptiles play big roles in the pollination of flowering plants

On paper, the tongue of a Pallas’ long-tongued bat (Glossophaga soricina) may sound a bit like something from a horror movie. The South American bat’s tongue is made of spongy, erectile tissue, allowing it to increase its length by 50 percent when engorged with blood. It’s covered in an array of tiny, densely-packed hairs, which then stand perpendicular to the tongue when fully extended, allowing it to better capture the fluids the bat devours to stay alive. In practice though, none of this seems very grotesque, because G. soricina only uses its tongue to lap up nectar out of flowers, placing this bat in a niche closer to a honeybee than a vampiric parasite.

Scientists studying pollinators have found that the importance of vertebrate pollinators like G. soricina may be widely underappreciated. For all the attention played to pollinating bees and butterflies, a large number of plant species largely depend on bigger critters like bats, mice and even lemurs to fertilize their flowers. These aren’t strictly fringe cases either, as some flowers have evolved to be highly specialized, and thus dependent on just the right species of mammal or bird to be able to reproduce.

Nectar-eating bats and birds

Among mammals, bats are the most common pollinators, sometimes accounting for 83 percent of fruit production in a geographic region. They’re known to pollinate close to 530 species of plants around the world, often in relatively exclusive arrangements. For example, the blue agave cactus (Agave tequilana) which is used to make tequila, only open their flowers at night in order to attract greater (Leptonycteris nivalis) and lesser (Leptonycteris yerbabuenae) long-nosed bats. These bats don’t have hairy tongues, but the hair on their bodies collect and spread pollen just like the fuzz on a bumble bee.

As the specialized beak and tongue of a hummingbird indicates, many species of our feathered friends also act as important pollinators. Beyond hummingbirds, 920 species of bird are known to spread pollen between flowers, and are estimated to account for five percent of flower fertilization where they live. In more isolated environments, like islands, that number goes up, with birds being responsible for at least ten percent of flower pollination.

No need to fly to flowers

The success of pollinating bees, bats and birds may suggest that flight is somehow necessary to pollinate a flower, but that’s not the case. Any animal that wants to sip nectar without destroying the flower that produced it can potentially act as a pollinator, which has lead to at least 85 plant species around the world that get regular visits from non-winged mammals. Mice, squirrels, possums and lemurs may all stick their noses into flowers enough to transport pollen. Even without fur, bluetail day geckos (Phelsuma cepediana) can act as pollinators, carrying sticky pollen on the tips of their noses.

As humans become more appreciative of how insect pollinators help keep ecosystems alive, this research shows that we need to also consider the bigger-bodied pollinators as well. As policies and even substitutes are being developed to help protect creatures we associate with plants humans grow on farms, we need to make sure the wider range of pollinators around the world are protected as well. After all, some of these pollinators have become very adept at their sticky, hairy line of work, and won’t be easily replaced.

Source: Lizards, mice, bats and other vertebrates are important pollinators too by Ecological Society of America, Phys.org

On April 8th, 2018 we learned about

Conservationists care for orphaned otters in oddly obscuring outfits

It’s so easy to fall in love with the adorable charm of a sea otter, possibly at the otter’s expense. As much as their cute faces and playful charisma may endear them to us, conservationists from the Monterey Bay Aquarium really don’t want the otters to reciprocate. Like all wild animals, sea otters stand a better chance at survival in the wild if they don’t learn to trust or rely on humans, even when orphaned at a young age. Young sea otters may need care, but only from surrogate otter mothers and people dressed as amorphous ninjas.

Finding the right role models

As their name implies, the surrogate mothers are female adult otters chosen to help raise orphaned pups. While they may never be released in the wild themselves, they ideally bond and help raise the pups, teaching tips on how to hunt, hide and live on their own. In some cases, the bond is strong enough that the surrogate will lunge, bite and squawk at human caregivers, helping the pup’s social development and reinforcing wariness towards humans, even if those humans mean the otters well.

Of course, identifying those humans may be tricky, as they dress like the aforementioned amorphous ninjas. To keep otter pups from learning to trust humans, any caregivers that hold, clean or feed the young pups dress in loose black smocks, clean lab gloves and a black welder’s mask. This way, if a young pup feels solace when being fed a bottle of “clamshake” from a human handler, they probably won’t ever see a similar handler again once released in the wild. They may grow up to find the sight of black garbage bags inexplicably comforting, but that should keep them from venturing into human-populated areas and developing dependencies on whichever people happen to be present. For the humans that are trained to help the orphaned otters, wearing the costume apparently doesn’t make the otters any less charming to care for.

Dressed for the otters’ success

These precautions may seem a bit extreme, but the success of the Monterey Bay Aquarium’s restoration projects indicates that they’re worth the effort. Since 1984, the Aquarium has been working to restore sea otter populations to their historic levels which had been reduced to tatters in the 18th and 19th centuries. At this point, the otters are no longer being hunted for their fur, but they have a ways to go before they can truly reclaim their historic range from Oregon to Baja Mexico. After raising and releasing 725 stranded otters, conservationists are seeing that the current challenges are based around a lack of kelp forests, making them venerable to sharks and making their preferred sea urchin diet less nutritious (as the urchins over-graze and then starve for more kelp.) It’s a rare scenario where an animal isn’t being directly threatened by human activity, not that they’d want a normal-looking human to get near them in the first place.

Source: Sea Otter Behavioral Changes and Adaptations in Contrasting Environments by Emily Loufek & Alicia Pereyra, Soundings

On April 1st, 2018 we learned about

Hunting regulations are reshaping how brown bears raise their young

Swedish brown bears are spending more and more time with their cubs, but it’s not thanks to needier offspring or any surge in maternal instincts. It’s actually been thanks to a process of elimination, as bears taking care of cubs can’t legally be hunted, meaning moms with an empty nest are more likely to be killed by humans. It’s one of a number of ways human activity is shaping bear behavior, as our activity puts pressure on some populations while protecting and encouraging others, possibly in ways we haven’t really considered.

Researchers investigated maternal behavior in Swedish brown bears (Ursus arctos) over the last 20 years to see how bans on hunting mother bears impacted their reproductive success. They originally assumed that hunting would push bears to wean their cubs at younger ages, trying to maximize their reproductive opportunities while they had the chance, similar to other animals that have been known to breed at younger ages when resources are scarce. However, the opposite proved true— bears that said goodbye to their cubs after one-and-a-half years were more likely to be hunted and removed from the overall population, while bears that stuck with their offspring for an additional year were more likely to survive. Over the course of two decades, the genes driving instincts for long-term parenting have had a chance to flourish, and these patient mothers are making up a larger and larger portion of bear populations.

An upside for offspring

The mother bears aren’t selfishly using their cubs as shields from hunting. A mother bear won’t mate until her cubs have moved on, and so male bears will attack offspring so the female will be more receptive to new suitors. Smaller cubs are obviously easier to attack, although bears that were on their own after a year and a half faced a 22 percent mortality rate.  Cubs that stayed with their mom were thus more successful, providing more benefits to bear family’s that stuck together. This may lead to some interesting consequences for non-hunting humans too, as mother bears in outside of Sweden have already been observed using human developments as safe havens from male bears that would harm cubs, meaning people may have to deal with an increasing number of urbanized bears as these trends continue.

These patterns all show how things like hunting regulations can make a big impact in ecosystems, even after hunting season has ended. While many governments impose regulations against hunting animals caring for young to try to keep populations stable, these rules may end up changing those populations as well. The number of bears in Sweden has been climbing, and more and more of those bears are sticking together in the safety of a family unit.

Source: Hunting regulation favors slow life histories in a large carnivore by Joanie Van de Walle, Gabriel Pigeon, Andreas Zedrosser, Jon E. Swenson & Fanie Pelletier, Nature Communications

On March 27th, 2018 we learned about

Providing food year-round promotes the growth of parasite-carrying bird populations

My son and I regularly grumble to each other about the people we see feeding ducks at a nearby park. It happens often enough that he doesn’t even bother repeating comments about how ducks shouldn’t be eating popcorn, and instead just sighs and rolls his eyes as well as a five-year-old can. While we’ve never handed out breadcrumbs to the local mallards, it turns out all these admonishments have been made from a bit of a glass house. Research is finding that other kinds of handouts, like the bird feeder we fill up on our porch, may also make a big impact on the health of migratory birds and potentially anyone that lives near them.

Feeders keep birds fat and infected

As we all learn at a young age, many bird species in North America migrate during the winter. When the weather gets colder, birds have a harder time finding enough food to eat, so they head south to warmer areas until spring. What’s less obvious to all of us is that those migrations strongly shape the bird’s ecology when they return home. Throughout the winter, migrating birds won’t be exposed to the same set of parasites that they encounter further north. This means that those parasite populations are weakened, making them less of a concern when the birds return. Those parasites also have to remain relatively gentle on their hosts, as a weaker, sicker bird is less likely to survive migrating in the first place, potentially cutting off the parasite’s lineage in the process.

Human-sourced food like bird feeders may be changing this balance. By making food available to bird year-round, a population of permanent residents may develop. Those birds continually interact with parasites, and can become more virulent in well-fed birds’ bodies. If that weren’t enough, the birds that never migrate are likely to lay claim to nesting sites before their traveling cousins’ return. Taken together, it means that birds that do still migrate will find themselves at a considerable disadvantage when they arrive in the spring.

Clean feeders in a migration-friendly yard

So what can you do if you don’t want to inadvertently train your local birds to stay home and strengthen strains of West Nile virus or other parasites? One option is try to plant as many native plants as you can, particularly looking for plants that co-evolved with your area’s native bird populations. While some conservationists advocate for the complete removal of bird feeders, a compromise might be to take steps to keep them clean. Make sure you regularly sweep out old food and husks, and clean feeders and bird baths to head off the transmission of pathogens. It won’t convince your local birds to head south, but it should help keep the birds that stay a bit healthier for the sake of those that still migrate each winter.

Source: Feeding wildlife can influence migration, spread of disease by University of Georgia, Phys.org

On March 11th, 2018 we learned about

People benefit from the dog-centric diets of leopards living in Mumbai

In 2014, researchers scoured Mumbai for poop to learn about the diet of the local leopard population. Around 35 of the big cats were known to live in the Sanjay Gandhi National Park, which is basically surrounded by human development. This obviously cut the leopards off from their usual menu of hooved mammals, so researchers were worried that they’d find a lot of livestock in the feces they collected. As it turned out, the leopards were eating some livestock like goats, but the majority of their meals were actually domesticated dogs (and cats), which may be really good news for the people living near the park.

Reducing the spread of rabies

As alarming as living near 35 hungry leopards may sound, the cats aren’t nearly the problem the 100,000 feral dogs are. It’s estimated that most of Mumbai is populated by around 1,700 dogs per square mile. Those dogs and their kin across India are thought to be responsible for the majority of the 20,000 people that die of rabies infections every year. So while leopards had seven reported attacks on humans in 2017, dogs are making a much bigger impact on life in the city. With laws restricting population control measures to sterilization programs, meaning the leopards are the most direct way to reduce the number of feral, and possibly rabid, dogs in Mumbai.

Based on the aforementioned fecal analysis, leopards appear to eat around 1,500 dogs per year, accounting for 39 percent of their diet. By eating that many dogs, researchers estimate that the leopards are saving humans from 1,000 bite incidents and as many as 90 cases of rabies. In doing so, they’re also effectively saving the overall community around $18,000 per year, factoring in medical costs, lost work time, and more direct animal management issues. These benefits aren’t equally distributed though, as the leopards only hunt near the park where they live. While the leopards are bold enough to stalk through parking garages, it’s only in their limited territory that dog populations are reduced to around 42 dogs per square mile.

Ecosystems produced by people

Going forward, researchers want people to better understand how these leopards are helping their community, partially saving them from a problem the humans created. Aside from human developments building over the leopard’s habitat, the dogs have likely gotten out of control thanks to a plunge in vulture populations across India. For the last 20 years, a drug used to treat cattle has been killing vultures that feast on carcasses, leaving that carrion for feral dogs instead. Dog populations grew, getting us to a point where they’ve become the focus of leopards’ diets. It may seem nice that the leopard’s are proving to be so adaptable, but researchers are concerned about how dependent they’ve become on human activity for their food. In a weird way, it’s almost like the early stages of domestication, but for large, bone-crushing cats instead of the dogs they’re now feeding on.

My five-year-old asked: How can they eat a goat? Can they eat the horns? Also, it’s sad that they eat kitties.

I wasn’t able to find proof of a leopard eating a goat’s horn, but big cats do regularly chew up and swallow the bones of their prey. Since horns are basically specialized bone tissue, a leopard could probably crush through it if the horn wasn’t too thick.

Not sure what to say about the feral cats getting eaten though, besides that my son is apparently not a dog-person.

Source: Urban Leopards Can Save Lives By Eating Feral Dogs by Matthew L. Miller, Cool Green Science

On March 6th, 2018 we learned about

Flamingos in Florida turn out to have been locals all along

Flamingos aren’t exactly subtle, and yet people in Florida have been having a hard time seeing them for the last hundred years. It wasn’t that the tall, pink birds had adopted a new form of camouflage, or become nocturnal. The problem was that, as far as anyone knew. They just weren’t supposed to be in Florida. Any birds that were spotted where therefore explained as escapees from human captivity, temporary visits during a migration, or misidentified pink spoonbills. It took a new series of sightings, plus a stubborn flamingo on Boca Chica Key, to finally make it clear that some wild flamingos do in fact call Florida home.

Presumably killed for plumage

The confusion started in the 1800s, because of hats. Flamingo feathers had become a fashionable addition to ladies’ hats, increasing demand for feathers to dangerous levels. Florida was home to some flamingos as the time, and the popular understanding was that that population was hunted to exhaustion in order to obtain feathers, not unlike the poaching of rhinos and elephants for their horns and tusks. The birds’ eradication seemed to be so complete that biologists had to check with historical records and specimens in museum collections to confirm that they’d ever really nested in Florida in the first place.

Obviously, flamingos have been spotted in Florida since the feather fad of the 19th century. However, they were then assumed to either be captive animals that escaped, in which case it was assumed that they’d be unsuited to survive in Florida and have minimal impact on the ecosystem. If a larger group was seen, they were expected to be birds from Mexico, Cuba or the Bahamas that were simply stopping over in Florida for a quick visit. However, without some way to track the movement of specific birds, this was all guesswork, which is why it was so lucky that a flamingo named Conchy was so uncooperative.

Tagging a non-traveler

Conchy was a flamingo that regularly turned up at a Navy airfield on Boca Chica Key. To avoid collisions with aircraft, people from the airfield would regularly scare off visiting flamingos with loud noises like fireworks or shotgun blasts. Conchy caught people’s attention though because he didn’t flee from these sounds, inadvertently volunteering to be tagged in the process. Once he was wearing a radio tag, researchers expected that they could track his travels back to his native Mexico or Cuba, confirming what everyone had ‘known’ about Floridian flamingos all along.

As it turned out, Conchy wasn’t into traveling. Not only did the stubborn bird not like to leave the Navy airfield, but he also didn’t ever leave Florida. While his radio tracker functioned, researchers saw that he basically stayed put around Florida Bay all year long, never needing to migrate. His genetics haven’t been traced to any of the historical samples from Floridian flamingos before the 19th century, but Conchy and his flock have proved that Florida should be considered a viable flamingo habitat.

Legally local

This is significant for legal purposes. Before this study, even tagging Conchy was a difficult issue, as researchers had to get special permission to purposely release a “non-native” animal into Florida. However, with the birds now recognized as natives, they’ve been taken off registries of exotic species, and instead will be treated as locals in the future.

My third-grader asked: Where do flamingos come from otherwise?

There are more than one species of flamingo, and as a group they can be found all around the world. Coasts in South America, the Yucatan Peninsula, Africa, the Mediterranean and India are all home to the mostly pink birds, although it’s the American flamingo (Phoenicopterus ruber) that’s now calling Florida home.

Source: Florida's Long-Lost Wild Flamingos Were Hiding In Plain Sight by Nancy Klingener, NPR

On March 5th, 2018 we learned about

Snakes can make a substantial, if indirect, impact on local plant life

At meal time, snakes aren’t terribly interested in plants. The slithering reptiles are carnivores, and thus don’t even have the teeth to tear at leaves, let alone chew them. That doesn’t mean that snakes have no influence on their local flora though. Researchers are learning that snakes can help, or severely hurt, plant life in their habitats, particularly in terms of seed dispersal.

Indirect seed-dispersal

This isn’t to say that snakes are out foraging on seeds, but they do end up pooping them out in new locations. This is thanks to the food that snakes are interested in; rodents like mice are likely to be carrying seeds in their own guts or cheek pouches when they get eaten by a snake. The snake is unlikely to harm any rodent-wrapped seeds while they swallow their meal, and so the seeds can survive a trip through the reptile’s digestive tract. Some seeds seem to do quite well this arrangement— out of the 971 seeds that were found in 50 snakes digestive tracts, a number were even starting to germinate in the snakes’ colons, upping the odds that they’d grow once deposited on the ground.

Interfering with birds’ pepper-seed-pooping

Snakes don’t always help with seed dispersal though. Brown tree snakes (Boiga irregularis) were brought to Guam in the 1940s, and have been a destructive invasive species ever since. Their biggest victims have been the island’s birds, as 10 of the 12 native species have been wiped out by snakes. This kind of change has understandably caused havoc in the local ecosystem, particularly with the local donne’ sali chili pepper.

The donne’ sali chili pepper is a native plant species that has played an important role in the region’s culture and economy. While it’s popular with people, its most important fans are the birds that feed on the fruit and then poop the seeds in new locations in the forest. The peppers that were “planted” by birds are said to be spicier than those raised on people’s farms, making the loss of birds a big problem. While the birds are faring well on other islands in the region, Guam’s pepper plants have been decimated thanks to the snakes’ impact on bird populations.

At this point, only a small number of Micronesian starlings (Aplonis opaca) are holding out on Guam, avoiding snakes in the forest around the Anderson Air Force Base. To help them out, conservationists have installed 200 nesting boxes on poles so the starlings can keep their eggs safe from the tree snakes. There are some efforts to curb the snake populations, but for now most efforts are on keeping the snakes contained while getting the birds to eat, and poop, more chili peppers.

Source: How an interloper snake decimated Guam’s delicious wild chilies by Jenny Howard, Massive

On March 4th, 2018 we learned about

African elephants are adapting to avoid interacting with dangerous humans

Humans aren’t very popular with elephants. However popular pachyderms may be in popular media, the cold reality is that we’re killing them at an alarming rate, and usually only to get a hold of their ivory tusks. With elephant populations having been reduced by more than 50 percent since the 1970s, it’s then understandable that the surviving animals are adapting to try and cope with humanity’s predatory behaviors. These changes cover all the bases, ranging from shifts in elephant behavior to possibly reshaping these iconic animals’ anatomy.

Survival strategies

The changes in behavior are probably possible due to the long and social lives of elephants. For example, matriarch elephants in the Gorongosa area of Mozambique survived over a decade of civil war in that country. During that time, those elephants grew up seeing their kin being killed for both meat and ivory while the county was in conflict, and it apparently taught them to be very wary of human beings. Today, those females have been observed sharing their fears to their families, fleeing or charging people they encounter 25 years after Mozambique’s war. Since elephants communicate through body language, sound and chemical cues, it’s safe to assume these matriarchs are passing their concerns on to the offspring.

This isn’t to say that elephants are blindly terrified of humans though. Elephants in Kenya’s Amboseli National Park can apparently differentiate between the sounds and scents of different groups of humans. They’ve been found to be much less concerned about the speech of farmers, while acting more cautious when wearing Maasai warriors that pose more of a threat to their safety.

One of the more systematic changes in elephant behavior is how they’ve been handling migrations. After a lone bull elephant traveled 130 miles to Somalia under the cover of darkness in 2016, researchers have been looking more closely at how and where elephants are moving. They’ve realized that elephants in sub-Saharan Africa are increasingly likely to travel at night, probably to avoid the threat of poachers during the day. Those migrations are also likely to target safe-havens for elephants, such as Botswana, where populations have increased by 30,000 since 1995.

Anatomical adaptations

Beyond how elephants act, researchers are seeing changes in how elephants look as well. Two to six percent of female African elephants never grow tusks thanks to natural variations in their genetics. Under happier conditions, being born tuskless would be a burden to these individuals, as they’d have a harder time getting food and water. Tuskless males also have a harder time competing for mates, possibly explaining why they’re even rarer in normal populations.

Poaching is acting as an evolutionary pressure though, essentially selecting against the animals with big, healthy tusks. Since those animals are more likely to be killed for their ivory, they’re less likely to live to produce offspring. As a result, tuskless elephants are effectively becoming the more “fit” variant, and their share of the overall elephant population is growing. In Gorongosa National Park, over 50 percent of the females that survived times of widespread poaching lacked tusks. This is compared to the 33 percent of tuskless females born in safer time periods.

My five-year-old asked: Is it against the law to kill elephants here?

We don’t have any native elephants in California, but that doesn’t mean that our laws can’t play a role in elephants’ survival. California was one of the biggest ivory importers in the United States, but California Fish and Game Code Section 2022 now bans just about every piece of ivory that might enter the state. Since most ivory traded around the world has been found to be from recently killed elephants, reducing the number of potential buyers will hopefully make selling ivory a seem less profitable to importers, smugglers and ultimately, poachers.

Source: African elephants are migrating to safety—and telling each other how to get there by Kanika Saigal, Quartz

On February 21st, 2018 we learned about

The sounds of snapping shrimp used by scientists, and whales, to estimate the abundance of coastal wildlife

Your alarm clock may play soft, soothing sounds of distant waves to help you nod off to sleep, but you’re only getting a tiny portion of the cacophony of noise echoing through the ocean. From whale greetings to acoustic gravity waves, there are a lot of vibrations moving through the water. Researchers are learning to listen in more carefully, as these sounds are a great way to monitor what’s happening in underwater ecosystems, although they may be a bit late to the party. Some studies are finding that the residents of the ocean, like Pacific gray whales, may regularly be tuning into specific sounds as indirect indicators of where to find a bite to eat.

Popping as a population proxy

One of the louder sea creatures capturing human and cetacean ears is the snapping shrimp. Like its infamous cousin, the mantis shrimp, this crustacean can snap its claw shut so quickly that it causes a tiny, temporary vacuum in the water, called a cavitation bubble. That bubble then collapses, releasing a lot of energy in the process, hopefully stunning the shrimp’s prey so it can capture its dinner. Like less dramatic bubbles, the bubbles also make a loud popping noise that can be heard from a considerable distance away.

When enough snapping shrimps are hunting at once, these pops start to sound like a bit like something sizzling and splattering in hot oil. Because it’s coming from groups of shrimp hunting at once, researchers have started using the sound to estimate shrimp populations and activity levels. For instance, summer waters off the coast of North Carolina see a 15 decibel increase, as shrimp crackle and pop up to 2,000 times a minute. In the winter, they calm down considerably, with no more than 100 pops being recorded in a minute.

Signaling snack time

Snapping shrimp surprised researchers off the coast of Oregon when they dipped a hydrophone into the water. The shrimp were previously unknown in the area, and yet they were clearly turning up in sizable numbers in researchers’ recordings. What’s more, the researchers apparently weren’t the only one’s listening for snapping shrimp, as Pacific gray whales often turned up when the shrimp started hunting.

The whales weren’t following the popping sounds to eat the shrimp though, as the noisy crustaceans just aren’t part of their diet. The best guess at this point is that the whales understood that the shrimp’s activity meant there was other food nearby. Since so much of the ocean is essentially devoid of food, following the sound of the popping bubbles saves the whales a lot of trouble. They’ve learned that when the shrimp are hunting, there’s probably something for whales to eat in the same location. With whales’ keen sense of hearing, the noisy bubbles must be hard to ignore.

Like those whales, ecologists are looking to figure out just how reliable a signal the snapping shrimp can be. If they’re consistent enough, listening for the sound of shrimp bubbles may be a relatively quick and inexpensive way to assess the health of coastal ecosystems, and maybe find some hungry whales at the same time.

Source: Snapping Shrimp May Act as 'Dinner Bell' For Gray Whales Off Oregon Coast, AGU.org