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The Bird That Impales Its Prey

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Wikimedia Commons

In one of our recent mental_floss videos, Emily Graslie introduced us to the shrikes, a family of birds with a nasty habit of impaling their prey on thorns and barbed wire fences. 

The birds’ feeding habits are hard to ignore, and common names for the birds around the world reflect the grisliness and perceived cruelty of them. In English-speaking countries, they’re known as butcherbirds. In East Africa, a shrike is called “jacky hangman.” The Dutch call them canary biters. The Germans have two great names for them—Neuntoter (“nine dead”) and Raubwurger (rauben, “to steal” + wurger, “strangler”).

Why do shrikes go all Vlad the Impaler on their prey? Over the years, biologists have offered several explanations. 

Shrikes lack the impressive talons of many other carnivorous birds, like eagles and owls, and instead rely solely on their beaks to kill and dismember prey. Impalement holds the prey in place and allows the shrikes to pull their meal apart and eat it, acting like the “fork” to their beaks’ “knives.” 

Impaled prey acts like a pantry for the birds, too, and they can return to a large impaled animal for several feedings, store food when prey animals are less active, or share the kills with their mates and offspring. A large cache of impaled critters might also advertise a shrike’s quality as a mate, and males with bigger larders have been shown to mate earlier and have more kids.

Letting prey hang out for a while could also let the shrikes feed on animals that other predators can’t exploit and don’t compete for. At least one species, the Loggerhead Shrike, regularly feeds on monarch butterflies and lubber grasshoppers—both of which have chemical defenses that make them unpalatable and even dangerous to other birds. The shrikes don’t eat these insects “fresh,” though, but only after letting them sit on a spike for a few days and allowing the toxins to degrade to the point where the insect is safe to eat. 

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These Deep-Sea Worms Could Live More Than a Thousand Years

Plunge below the sparkling surface of the Gulf of Mexico, head down into the depths, and there you'll find the ancient ones, growing in clusters of drab tubes like piles of construction equipment. Scientists writing in the journal The Science of Nature report that some of these worms could be more than 1000 years old.

When it comes to marine organisms, the deeper you go, the slower and older life gets. Biologists have found an octopus that guarded her eggs for four and a half years. They've seen clams born during the Ming dynasty and sharks older than the United States. They've seen communities of coral that have been around for millennia.

Previous studies have shown that some species of tube worm can live to be 250 years old. To find out if the same was true for other species—in this case, the Gulf of Mexico's Escarpia laminata—researchers spent years watching them grow. They used a long-lasting dye called Acid Blue to mark six clusters of worms, then let them to go about their wormy business. A year later, they collected all 356 blue-stained tubes and brought them back to the lab to measure their growth.

By calculating the speed of the worms' growth and comparing it to the size of the largest individuals, the scientists could devise a pretty good estimate of the oldest worms' age.

And boy, are they old. The researchers' worm-growth simulation suggested that the most ancient individuals could be more than 9000 years old. This seems incredible, even for tough old tube worms, so the scientists calculated a more conservative maximum age: a mere 1000 years.

A millennium-long lifespan is an extreme and not the average, the paper authors note. "There may indeed be large E. laminata over 1000 years old in nature, but given our research, we are more confident reporting a life span of at least 250 to 300 years," lead author Alanna Durkin of Temple University told New Scientist.

Still, Durkin says, "E. laminata is pushing the bounds of what we thought was possible for longevity."

She's excited by the prospect of finding older creatures yet.

"It's possible that new record-breaking life spans will be discovered in the deep sea,” she says, “since we are finding new species and new habitats almost every time we send down a submersible.”

 

[h/t New Scientist]

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Animals
Watch as Hummingbirds Fly, Drink, and Flap Their Tiny Wings in Slow Motion
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Hummingbirds have more feathers per inch than nearly any other bird, but it’s hard to fully appreciate their luminescent colors when they beat their wings between 70 to 200 times per second.

For the enjoyment of birders everywhere, National Geographic photographer Anand Varma teamed up with bird biologists and used a high-speed, high-resolution camera to capture the tiny creatures in slow motion as they flew through wind tunnels, drank artificial nectar from a glass vessel, and shook water from their magnificent plumage.

[h/t The Kid Should See This]

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