CLOSE
Original image
Tuan Cao via Wikimedia Commons

These Spiders Use Unlikely Bodyguards

Original image
Tuan Cao via Wikimedia Commons

Many ant species are territorial and aggressive. That maybe wouldn’t be so bad if ants were loners, but they tend to stick together in groups, sometimes tens of thousands strong. If you’re a bigger, tougher animal that eats ants, or one that stays safe by mimicking them, or makes your living as an ant parasite, those numbers are great. They make it that much easier to prey on them or blend in with a group. 

The jumping spider Phintella piatensis neither eats ants nor mimics them. It’s not a parasite, either, but it still loves hanging out with ants. In one field study, 90 percent of all Phintella spiders that biologists found were in the company of ants, including the Asian weaver ant Oecophylla smaragdina. This has had puzzled scientists because Oecophylla is known as a formidable predator with a taste for arachnids, and yet Phintella is drawn to them and doesn’t seem to come into harm’s way when it’s around them. In experiments, Phintella’s survival rate among the ants was much higher than those of other regular jumping spiders, and closer to spiders that eat or mimic the ants. 

What would drive Phintella into the company of an ant that it should be afraid of, scientists wondered, when there doesn’t seem to be any benefit? And why doesn’t the ant make a meal of it?

The answer to the first question is “something scarier than an ant.” For jumping spiders in the Philippines, that would be the spitting spiders of the genus Scytodes. While most spiders deliver venom from their teeth and spin silk into webs, these guys turn both into projectile weapons. They mix liquid silk and venom into a sticky fluid and “spit” it at prey, at once trapping it and poisoning it. The spider then approaches its prey and bites it, delivering another dose of venom that begins to liquefy its tissues. Phintella is a frequent victim of this hunting technique, and Scytodes spiders are known to build their webs directly over Phintella’s nests and attack the smaller spiders as they come and go from their homes. 

Scytodes stays far away from weaver ants, though, which got New Zealand biologists Ximena Nelson and Robert Jackson thinking that the jumping spiders hang out with the ants for protection. When they got the three arthropods together in the lab, they found that jumping spiders were more likely to build nests when they could see or smell ants than when other insects were around or there was no sign of ants. The spitting spiders, on the other hand, were much less likely to build their webs when they could see the ants. They were also more likely to die when the ants were around, while the jumping spiders largely avoided becoming ant food. 

To Nelson and Jackson, the differing nest-building responses and survival rates between the two spiders made it pretty clear that Phintella sticks close to the ants because they scare away or kill spitting spiders. And while ants would be happy to eat the jumping spiders, too, Phintella has a few tricks up its sleeves that turn enemy territory into a safe haven. 

First, jumping spider nests aren’t like typical spider webs. They’re more like silken cocoons, and provide some resistance to intruders. Phintella then beefs up the nest’s security even more with a tough, dense weave of silk that the ants have a hard time tearing through. It also adds hinged flaps to either end of the nest that act like doors. The spider can get in and out of the nest as it pleases and close the flap behind it to keep the ants out. 

Original image
iStock
arrow
Big Questions
Why Do Cats Love Scratching Furniture?
Original image
iStock

Allergy suffering aside, cat ownership has proven health benefits. A feline friend can aid in the grieving process, reduce anxiety, and offer companionship.

The con in the cat column? They have no reservations about turning your furniture into shredded pleather. No matter how expensive your living room set, these furry troublemakers will treat it with the respect accorded to a college futon. Do cats do this out of some kind of spite? Are they conspiring with Raymour & Flanigan to get you to keep updating home decor?

Neither. According to cat behaviorists, cats gravitate toward scratching furniture mostly because that love seat is in a really conspicuous area [PDF]. As a result, cats want to send a message to any other animal that may happen by: namely, that this plush seating belongs to the cat who marked it. Scratching provides both visual evidence (claw marks) as well as a scent marker. Cat paws have scent glands that can leave smells that are detectable to other cats and animals.

But it’s not just territorial: Cats also scratch to remove sloughed-off nail tips, allowing fresh nail growth to occur. And they can work out their knotted back muscles—cramped from sleeping 16 hours a day, no doubt—by kneading the soft foam of a sectional.

If you want to dissuade your cat from such behavior, purchasing a scratching post is a good start. Make sure it’s non-carpeted—their nails can get caught on the fibers—and tall enough to allow for a good stretch. Most importantly, put it near furniture so cats can mark their hangout in high-traffic areas. A good post might be a little more expensive, but will likely result in fewer trips to Ethan Allen.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

Original image
iStock
arrow
Animals
7 Fun Facts for Elephant Appreciation Day
Original image
iStock

Happy Elephant Appreciation Day! Celebrate the occasion with some facts about everyone's favorite gentle giant. 

1. ELEPHANTS CAN RECOGNIZE OTHER ELEPHANT CARCASSES.

iStock

The University of Sussex's Karen McComb told National Geographic that elephants "become excited and agitated if they come across a dead elephant," and, in particular, will investigate skulls and tusks. McComb teamed up with researchers at the Amboseli Elephant Research Project in Kenya to study the behavior, showing wild elephants a range of objects that included skulls. They found that the elephants examined skulls—and tusks in particular—of their own kind twice as long as other skulls, and examined tusks six times as long as they did pieces of wood. They were even able to recognize elephant skulls with the tusks removed, but didn't show preference for certain elephant skulls over others, which suggests they didn't know which skulls belonged to their own relatives. "Animals that are intensely social in life may be most likely to display an interest in their dead," McComb told National Geographic. "But what goes on in their minds while they are doing this is a total mystery."

2. THEY'RE SCARED OF BEES.

iStock

Forget about mice scaring off elephants: When farmers need to keep elephants away from their crops, they should use bees. Researchers in Kenya discovered that even the recorded sound of buzzing bees was enough to make elephants retreat—and cause them to emit a low-frequency sound, inaudible to humans, that warns other elephants of the bees' presence.

"It's impossible to cover Africa in electric fences," Lucy King, author of the paper, told The Huffington Post. "The infrastructure doesn't exist in many places and it would restrict animals' movement." But something like a bee fence—hives strung on strong wires a certain distance apart that would move when elephants walked into them, disturbing the hives—"could be a better way to direct elephants away from farmers' crops," she said.

3. THEY MIGHT UNDERSTAND POINTING.

iStock

Humans often use pointing as a way to nonverbally get a message across, though not many other animals grasp the concept. But according to a two-month study of 11 tame African elephants, these pachyderms might be able to: When presented with two identical buckets and pointed in the direction of the one containing food, elephants picked up on the cue fairly consistently: Elephants had a success rate of 67.5 percent (1-year-old humans have a success rate of 72.7 percent). But an earlier study of Asian elephants indicated that they don’t notice pointing gestures, which is a bit of a mystery.

4. ONE ELEPHANT CAN "TALK." 

iStock

Koshik, an elephant in a South Korean zoo, developed the ability to imitate the sounds of five words he's heard from his trainer—annyeong (hello), anja (sit down), aniya (no), nuwo (lie down), and joa (good)—by sticking his trunk in his mouth. The scientists who first noticed Koshik’s ability speculate that he learned to “talk” because he was lonely.

5. THEY'RE DIGITIGRADES.

iStock

It's Latin for "finger walking," and what it means is that elephants walk on their toes (there are five of them, as well a sixth false toe). According to the book Mammal Anatomy: An Illustrated Guidemost of the animals' weight "rests on a broad pad of elastic tissue behind the toes" which "acts as a shock absorber and prevents the skeleton from jolting too much when the animals walk. It also allows elephants to move surprisingly quietly despite their size."

6. AN ELEPHANT PREGNANCY LASTS ABOUT TWO YEARS.

iStock

If you thought being pregnant for nine months was a long time, be glad you're not an elephant, which can be pregnant for up to 680 days, according to the BBC. All that time in the oven has a benefit, though: Elephant calves are born with highly-developed brains, capable of learning their herd's complex social structures and ready to put their trunks to use.

7. NINETY-SIX ELEPHANTS ARE KILLED IN AFRICA EVERY DAY.

iStock

Unfortunately, elephant poaching remains a very big problem: An estimated 35,000 elephants are killed annually, their tusks sold illegally in the ivory market. Do the math, and that comes out to nearly 96 elephants every day. Find out what you can do to help elephants and stop poaching at 96Elephants.org.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios