15 Facts About the Lion’s Mane Jellyfish

The stunning—and stinging—lion’s mane jellyfish (Cyanea capillata) ranks among earth’s most beautiful creatures. Let's tip our scuba masks to this amazing invertebrate.

1. It Can Grow Up to 120 Feet Long.

By comparison, the largest recorded blue whale was a paltry 108 feet long. But don’t go around calling this jellyfish the world’s longest animal. Some marine biologists claim the saltwater bootlace worm (Lineus longissimus) deserves that title—when fully extended, it can stretch 180 feet from end to end!

2. It Eats and Expels Waste Through the Same Orifice.

Jellyfish have a very special opening designed to perform double-duty as both a mouth and an anus. At least they’re economical.

3. It Isn’t Immune to Predation.

As you can see in this clip (filmed by National Geographic), lion’s mane jellyfish need to watch their backs around famished anemones. Also, leatherback sea turtles have been seen gobbling them up off the coasts of Canada. The reptiles' throats contain backward-pointing spikes called oral papillae to help move food in the direction of the stomach; they also make escaping pretty difficult.

4. Lion’s Mane Jellyfish Come in a Variety of Colors.

Large individuals are often red or purple, while smaller specimens tend to be shades of tannish-orange.

5. A Single Specimen May Have Stung Over 50 People.

June 16, 2010 was a weird day for New England beach-goers. Somewhere between 50 and 100 swimmers were stung off the coasts of Rye, New Hampshire and, when a 40-pound lion’s mane corpse was found at the scene, the authorities felt they’d found their perpetrator. But could a solitary jellyfish really inflict so much mayhem?

“It’s certainly not common,” marine biologist Sean Colin told LiveScience, “but it’s certainly within the realm of possibility because they do have so many tentacles if they’re that large.” Colin hypothesizes that, since dead jellies can still sting, maybe the body was broken up into several large chunks which spread out and contacted unsuspecting visitors. We’ll probably never know for sure.

6. These Guys Can Have up to 1200 Tentacles.

These are arranged in eight sets that contain between 70 and 150 individual tentacles apiece. Now there’s some Grade-A nightmare fuel…

7. Unfortunately, a Famous Picture was Faked.

As far as being awesome is concerned, nature doesn’t need the Internet’s help. Perhaps you’ve seen this photo, which happens to be Google Images’ number one search result for “giant jellyfish.” Many blogs and news sites have claimed that this thing is an especially-large lion’s mane jellyfish. But so far as we know, this species has a maximum diameter of only seven and a half feet—far smaller than the monster pictured here. What gives? As you might have guessed, it's Photoshopped.

8. It Makes Do With a Year-Long Lifespan.

Believe it or not, one type of jellyfish may be functionally immortal. Sadly, the lion’s mane jelly doesn’t follow suit.

9. The Lion’s Mane Jellyfish Like it Cold.

Geir Friestad, Flickr

Frequent denizens of harsh, Arctic waters, lion’s mane jellyfish are seldom seen below the northern 42nd parallel. Also, they gravitate towards the surface and almost never venture beneath depths of 66 feet.

10. Like Other Jellyfish, It Reproduces Both Sexually and Asexually.

Jellies take on several forms in their complicated life cycles. Upon entering what’s called the “medusa” stage and becoming “adults,” they can reproduce by releasing sperm and eggs. However, as stationary entities rooted to the ocean floor while in the “polyp” stage, they’re capable of asexually cloning themselves.

11. Also Like Other Jellyfish, It (Technically) Lacks a Brain.

Derek Keats, Flickr

In all fairness, contrary to popular belief, these animals do have central nervous systems—a ring of nerves can be found nestled in their “hoods” (or “bells”). So there.

12. Some Scientists Think That Their Population is Booming

Though the jury’s still out, many have argued that—due to factors like over-fishing and rising global sea temperatures—jellyfish numbers may be skyrocketing. Who knows? If true, this might mean we’ll all start munching on more dried jellies at seafood restaurants.

13. Lion’s Mane Jellies Tend to Group Up.

A.Davey, Flickr

C. capillata sometimes swim together in huge, kilometer-wide clusters called “shoals.”

14. Schools of Fishes Often Surround Them

While deadly to smaller animals (including other jellyfish), lion’s mane jellyfish stings don’t have much of an effect on fish of the Caranx genus, which actively seek the invertebrates out and hover near their tentacles for protection.

15. Sherlock Holmes Once Had to Contend with a Lion’s Mane Jellyfish.

The world’s greatest detective had never faced a squishier adversary. In The Adventure of the Lion’s Mane (1926), he deduces that an unlucky professor had been stung to death by one of these spineless predators—which he proceeds to track down and flatten with a boulder. No word on whether or not we’ll be seeing Benedict Cumberbatch go toe-to-tentacle with one.

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How Bats Protect Rare Books at This Portuguese Library
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Visit the Joanina Library at the University of Coimbra in Portugal at night and you might think the building has a bat problem. It's true that common pipistrelle bats live there, occupying the space behind the bookshelves by day and swooping beneath the arched ceilings and in and out of windows once the sun goes down, but they're not a problem. As Smithsonian reports, the bats play a vital role in preserving the institution's manuscripts, so librarians are in no hurry to get rid of them.

The bats that live in the library don't damage the books and, because they're nocturnal, they usually don't bother the human guests. The much bigger danger to the collection is the insect population. Many bug species are known to gnaw on paper, which could be disastrous for the library's rare items that date from before the 19th century. The bats act as a natural form of pest control: At night, they feast on the insects that would otherwise feast on library books.

The Joanina Library is famous for being one of the most architecturally stunning libraries on earth. It was constructed before 1725, but when exactly the bats arrived is unknown. Librarians can say for sure they've been flapping around the halls since at least the 1800s.

Though bats have no reason to go after the materials, there is one threat they pose to the interior: falling feces. Librarians protect against this by covering their 18th-century tables with fabric made from animal skin at night and cleaning the floors of guano every morning.

[h/t Smithsonian]

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Honey Bees Can Understand the Concept of Zero
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The concept of zero—less than one, nothing, nada—is deceptively complex. The first placeholder zero dates back to around 300 BCE, and the notion didn’t make its way to Western Europe until the 12th century. It takes children until preschool to wrap their brains around the concept. But scientists in Australia recently discovered a new animal capable of understanding zero: the honey bee. According to Vox, a new study finds that the insects can be taught the concept of nothing.

A few other animals can understand zero, according to current research. Dolphins, parrots, and monkeys can all understand the difference between something and nothing, but honey bees are the first insects proven to be able to do it.

The new study, published in the journal Science, finds that honey bees can rank quantities based on “greater than” and “less than,” and can understand that nothing is less than one.

Left: A photo of a bee choosing between images with black dots on them. Right: an illustration of a bee choosing the image with fewer dots
© Scarlett Howard & Aurore Avarguès-Weber

The researchers trained bees to identify images in the lab that showed the fewest number of elements (in this case, dots). If they chose the image with the fewest circles from a set, they received sweetened water, whereas if they chose another image, they received bitter quinine.

Once the insects got that concept down, the researchers introduced another challenge: The bees had to choose between a blank image and one with dots on it. More than 60 percent of the time, the insects were successfully able to extrapolate that if they needed to choose the fewest dots between an image with a few dots and an image with no dots at all, no dots was the correct answer. They could grasp the concept that nothing can still be a numerical quantity.

It’s not entirely surprising that bees are capable of such feats of intelligence. We already know that they can count, teach each other skills, communicate via the “waggle dance,” and think abstractly. This is just more evidence that bees are strikingly intelligent creatures, despite the fact that their insect brains look nothing like our own.

Considering how far apart bees and primates are on the evolutionary tree, and how different their brains are from ours—they have fewer than 1 million neurons, while we have about 86 billion—this finding raises a lot of new questions about the neural basis of understanding numbers, and will no doubt lead to further research on how the brain processes concepts like zero.

[h/t Vox]

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