How Spiders Surf the Wind For Miles on Strands of Silk

iStock
iStock

Spiders may very well be hairy and scary, but at least they can’t fly … right? Well, that depends on your definition of flight. As The New York Times reports, new aeronautical research is shedding light on the little-understood phenomenon of “ballooning,” which lets spiders span great distances—even oceans—by riding the wind like paragliders.

Moonsung Cho, an aeronautical engineer, started researching “spider flight” after witnessing a spider being carried by the wind in Denmark. Scientists have long known that spiders sometimes use flight to evade threats or seek food and mates in other locations, but prior to this study, the physics of how it actually works remained fuzzy.

Cho and his colleagues brought crab spiders back to the laboratory and used a wind tunnel to observe their response in a controlled setting. They discovered that a spider will use its leg as an anemometer, lifting one limb to test the strength of the wind. (Their idea of perfect flying weather is a light breeze of about 7 mph.)

Then, the spider lifts up its abdomen, shoots strands of silk skyward, and lets itself be carried off into the sunset. These strands of silk are far thinner than a strand of human hair and can measure up to 6 feet long. As Live Science puts it, a strand of silk contorts when it’s caught in the wind, thus “catching air like an open parachute.” This lets spiders surf the air current, at least for a few miles.

Instances of “spider flight” have been witnessed all over the world. Residents of one Australian town reported seeing a “tunnel of webs” in the sky back in 2015. Spiders sometimes migrate en masse, and although they use the wind to move about, they can’t control where they end up. Some have even landed on islands in the middle of the ocean.

Check out this video from The New York Times to learn more ballooning.

[h/t The New York Times]

Aspiring Eagle Scout Is Turning Old Fire Hoses Into Hammocks for Big Cats

iStock.com/tane-mahuta
iStock.com/tane-mahuta

Boy Scouts have to demonstrate skills in multiple areas to graduate to the rank of Eagle Scout. On his quest to reach the top rank in scouting, eighth-grader Payton Crawford is doing something that's unusual for the organization: Knitting hammocks for senior big cats out of old fire hoses, CBS Denver reports.

For his Eagle Scout project, the 11-year-old boy from Colorado wanted to help the Wild Animal Sanctuary in Keenesburg, Colorado. The nonprofit rescues large carnivores from abusive situations and gives them a new home in a 10,000-acre wildlife refuge. There are more than 500 animals living at the site.

When they're not roaming the sanctuary, older big cats like lions, tigers, and leopards will be able to lounge on Crawford's supportive hammocks. He gathered old hoses from fire departments, cut them into the desired lengths, and wove them into hammocks big enough to accommodate a variety of animals. He can make one himself in about two hours, but he needs help carrying the final product.

“It’s just something different that I wanted to try out,” he told CBS. “Give them a better life because they don’t have the luxury we do.”

You can see how Crawford put them together in the video below.

[h/t CBS Denver]

10 Colorful Facts About Cassowaries

iStock/BirdImages
iStock/BirdImages

All birds are living dinosaurs, but the dagger-clawed cassowary especially looks the part. Even wildlife biologists call cassowaries the world's most dangerous bird—and yes, it has been known to kill people. Here’s everything you need to know about the majestic and terrifying beast.

1. The southern cassowary is Earth's second-heaviest bird.

Scientists recognize three living species of cassowary—all of which live in New Guinea, northeastern Australia, and nearby islands. The dwarf cassowary is the smallest, with an average height of around 3 feet. The northern cassowary, an orange-throated behemoth, can stand nearly 5 feet tall. The southern cassowary is bigger than both at 5 foot 6 inches tall. The only two birds that grow taller are ostriches and emus. Adult southern cassowary females can weigh up to 157 pounds, and males 121 pounds, making them the second-heaviest birds on the planet behind ostriches.

2. Cassowaries have dangerous feet.

In the southern cassowary's Australian range, you might come across warning signs that read “Be Cass-o-wary.” Heed this advice. Normally, cassowaries are shy and reclusive, but they can become aggressive when threatened and strike back with powerful head-butts and pecks. Their most dangerous weapon is the razor-sharp claw on the middle toe of each foot, which, in southern cassowaries, grows to be 5 inches long. The birds deliver a series of downward kicks that have been known to break bones and cause fatal lacerations. 

3. Rearing cassowary chicks is the father's job.

Female cassowaries breed with several partners. After laying her eggs, she abandons them, at which point the males take over and incubates the eggs for at least 50 days. The fathers never leave the nest, not even to eat or drink. Once the eggs hatch, males spend the next nine months raising and defending the chicks. Males also teach the chicks how to forage so they can fend for themselves.

4. Cassowaries are surprisingly good jumpers.

What’s scarier than a 150-pound modern dinosaur with killer claws? One that can leap 7 feet off the ground. To get the most out of those toe daggers, cassowaries will sometimes jump feet-first at an attacker, with the claws slashing downward in midair. They’re also great swimmers and sprinters with a top running speed of 30 miles per hour.

5. Cassowaries have a spike hidden on each wing.

Cassowaries are closely related to emus and more distantly related to ostriches, rheas, and kiwis. All of these birds, known as ratites, are flightless. Cassowaries have small vestigial wings tipped with a small claw that probably serves no purpose.

6. Cassowaries are frugivores that also eat their own poop.

Wild cassowaries dine mainly on fruits and berries that fall to the ground in the rainforests they call home. A typical southern cassowary can eat up to 11 pounds of fruit a day, along with plenty of fungi and the occasional dead animal for some extra protein.

Cassowaries also hunt rodents, snails, and lizards. Poop is yet another item on the menu. Cassowary poop usually contains half-digested fruit, which still has plenty of nutritional value, so the birds devour each other’s droppings as well as their own. 

7. The function of their odd crests, or casques, is a mystery. 

Cassowaries sport royal-blue necks and shaggy black feathers, but their most distinctive feature is the helmet-like casque that sits above the eyes. The bony protrusion is covered with a sheath of keratin (the material that makes up your fingernails), and it begins to develop when the bird is around 2 years old. Scientists have long speculated, sometimes wildly, about its purpose. One theory is that casques help cassowaries push aside forest underbrush. The casques might also be used to attract the opposite sex.

A more interesting hypothesis involves how these birds communicate. Cassowaries emit very deep bellows—the lowest bird calls known to humans. Perhaps their casques amplify and broadcast these sounds by acting as a resonance chamber. Certain crested dinosaurs (like Parasaurolophus of Jurassic Park fame) may have produced calls the same way.

8. Cassowaries can live for decades (at least in zoos).

Naturalists don’t know how long a wild cassowary can expect to live. A few southern cassowaries have reached their 40th birthdays in captivity. In zoos, northern cassowaries can top that figure—one reached the age of 48 and another may have been as old as 61. The average lifespan for captive dwarf cassowaries is about 26 years.

9. Cassowaries have strange genitalia.

Both sexes have a pseudo-penis that isn’t connected to any of their internal reproductive organs. When cassowaries mate, the male ejaculates through his cloaca, an orifice at the base of the pseudo-penis. When they aren’t mating, males' pseudo-penis is turned inside out and retracted.

Such peculiar anatomy has given the cassowary a unique place in New Guinean culture and folklore. For example, the native Mianmin people tell stories about a human woman with a penis who somehow transformed into a cassowary. Another indigenous group, the Umeda, put on a regular ceremony called “ida.” A big event that lasts for two days and nights, the ritual involves a fertility dance which calls for two male dancers who represent a pair of cassowaries. Each player is given a heavy mask and is coated with charcoal from head to toe.

10. At least two unfortunate humans have been killed by cassowaries. 

To date, there have been only two verified reports of a cassowary taking human life. In April 1926, a cassowary fatally charged 16-year-old farmer Phillip McLean in north Queensland, Australia. More recently, a 75-year-old Florida man was killed by a cassowary he had kept as a pet at his exotic bird farm.

In 1999, Queensland Parks and Wildlife ranger Christopher P. Kofron analyzed 150 documented cassowary-on-human attacks. Twenty-two percent of attacks resulted from the bird defending itself, its eggs, or its chicks, 5 percent were triggered by somebody getting too close to the cassowary’s food, and 73 percent involved a cassowary that associated people with free meals. Many cassowaries in Australia had lost their natural shyness around humans thanks to people feeding them bananas and watermelon. Today, feeding a wild one is against the law, but the practice continues.

SECTIONS

arrow
LIVE SMARTER