acevvvedo via Flickr // CC BY-NC 2.0
acevvvedo via Flickr // CC BY-NC 2.0

Hawaii's Big Island Is Overrun With Loud Frogs From Puerto Rico

acevvvedo via Flickr // CC BY-NC 2.0
acevvvedo via Flickr // CC BY-NC 2.0

Hawaii’s Big Island is overrun with a very tiny—and very loud—frog. Native to Puerto Rico, the coquí frog is about the size of a quarter. It compensates for its diminutive size with its incessant cry: the shrill, high-pitched "Ko Keee ... Ko KEEE” from which it derives its name.

While the frog is beloved in its homeland, Hawaiians feel a tad differently, according to The Washington Post. The coquí isn’t native to the Big Island—scientists think it arrived via some potted plants sometime in the 1980s—and their evening mating calls can reach up to 90 decibels. Not only are coquís as loud as a lawnmower, they’re also incessant. Their din lasts from dusk to dawn, disturbing locals at night.

Complicating matters, the coquí has no natural predators in Hawaii, and it's thrived in its new environment, thanks to a plentiful bug population and a rocky habitat full of hiding places. It skips the tadpole stage, so it doesn’t require ponds. As a result, the Big Island’s coquí population is now three times greater than it is in Puerto Rico. (According to one study [PDF], there are 91,000 frogs per 2.5 acres; other reports vary, saying there could be more than 10,000 frogs per acre or between 20,000 and 50,000 per acre.)

Essentially, the coquí is comparable to a bunch of raucous party-goers who weren’t invited over, but showed up anyway—and now they won’t go home. Even more troubling: officials worry that the coquí will harm the local ecosystem by consuming pollinating insects, or hurt export plant sales, the Los Angeles Times reports.

Naturally, Hawaiians are fed up—and they're taking matters into their own hands. Neighborhood watch groups hunt for coquí at night (they’re silent during daytime), and kill them by trapping them in a Ziploc bag and freezing them, according to the Post. The LA Times reports that some individuals douse coquí habitats with citric acid spray, spray vegetation with hot water, or relegate flowers to freezers for a few days to get rid of the animals.

The Wall Street Journal writes that Hawaii’s Big Island had declared a coquí “state of emergency” by the mid-2000s. However, task forces have since reported that they’re resigned to the fact that the coquí is here to stay. It’s impossible to eradicate—so officials have switched gears, and are now focused on containment.

Meanwhile, some animal advocates have set up frog sanctuaries and nature preserves for the coquí. Others try to catch the pesky amphibians and ship them back to Puerto Rico. Many are simply becoming acclimated to the frog’s din. For the time being, it looks like the coquí isn’t going anywhere—so Big Island residents might want to stock up on earplugs.

[h/t Washington Post, Los Angeles Times, Wall Street Journal]

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Big Questions
Why Do Dogs Crouch Forward When They’re Playing?
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Whether they're tilting their heads or exposing their bellies for rubs, dogs are experts at looking adorable. But these behaviors do more than elicit squeals from delighted humans; in many cases, they serve important evolutionary functions. A prime example is the "play bow": If you've ever seen a dog crouch forward with its elbows on the ground and its rear end in the air, wagging tail and all, then you know what it is. The position is the ultimate sign of playfulness, which is important for a species that often uses playtime as practice for attacking prey.

The play bow first evolved in canids as a form of communication. When a dog sees another dog it wants to play with, it extends its front paws forward and lifts up its behind as a visual invitation to engage in a friendly play session. Dogs will "bow" in the middle of playtime to show that they're having fun and wish to continue, or when a session has paused to signal they want to pick it back up. Play bows can also be a sort of apology: When the roughhousing gets too rough, a bow says, “I’m sorry I hurt you. Can we keep playing?”

Play between canines often mimics aggression, and starting off in a submissive position is a way for all participating parties to make sure they’re on the same page. It’s easy to see why such a cue would be useful; the more puzzling matter for researchers is why the ancestors of modern dogs evolved to play in the first place. One theory is that play is crucial to the social, cognitive, and physical development of puppies [PDF]. It’s an opportunity for them to interact with their own kind and learn important behaviors, like how to moderate the strength of their bites. Play also requires the animals to react quickly to new circumstances and assess complex actions from other dogs.

Shiba inus playing outside.
Taro the Shiba Inu, Flickr // CC BY 2.0

Another evolutionary explanation is that playtime prepares puppies for the hunting they do later as adults. Watch two puppies play and you’ll see them stalking, biting, and pouncing on one another—all behaviors canines exhibit in the wild when taking down prey.

Of course, it’s also possible that dogs simply play because it’s fun. This is a strong case for why pet dogs continue to play into adulthood. “Devoting a lot of time to play may be less advantageous for a wild species who spends much of its time hunting or foraging for food, searching for mates, or avoiding predators,” Dr. Emma Grigg, an animal behaviorist and co-author of The Science Behind a Happy Dog, tells Mental Floss. “Many domestic dogs are provisioned by humans, and so have more time and energy to devote to play as adults.”

Because play is a lifelong activity for domestic dogs, owners of dogs of all ages have likely seen the play bow in person. Wild canids, like wolves, foxes, and coyotes, tend to reserve this behavior for members of their own species, but pet dogs often break out the bow for their humans—or anyone else who looks like they might be up for a play session. Grigg says, “One of my dogs regularly play bows to her favorite of our cats.”

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Animals
Why Crows Hold Noisy Funerals for Their Fallen Friends
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The next time you hear a murder of crows cackling for no apparent reason, show a little respect: You may have stumbled onto a crow funeral. Crows are among the few animals that exhibit a social response to a dead member of their species. Though their caws may sound like heartbroken cries, such funerals aren't so much about mourning their fallen friends as they are about learning from their mistakes.

In the video below from the PBS series Deep Look, Kaeli Swift, a researcher at the University of Washington's Avian Conservation Lab, investigates this unusual phenomenon firsthand. She familiarized herself with a group of crows in a Seattle park by feeding them peanuts in the same spot for a few days. After the crows got used to her visits, she returned to the site holding a dead, taxidermied crow and wearing a mask and wig to hide her identity. The crows immediately started their ritual by gathering in the trees and crying in her direction. According to Swift, this behavior is a way for crows to observe whatever might have killed the dead bird and learn to avoid the same fate. Flocking into a large, noisy group provides them protection from the threat if it's still around.

She tested her theory by returning to the same spot the next week without her mask or the stuffed crow. She offered the crows peanuts just as she had done before, only this time the birds were skittish and hesitant to take them from her. The idea that crows remember and learn from their funerals was further supported when she returned wearing the mask and wig. Though she didn't have the dead bird with her this time, the crows were still able to recognize her and squawked at her presence. Even birds that weren't at the funeral learned from the other birds' reactions and joined in the ruckus.

Swift was lucky this group of crows wasn't particularly vengeful. Crows have been known to nurse and spread grudges, sometimes dive-bombing people that have harmed one of their own.

[h/t Deep Look]

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