14 Fascinating Facts About Ocean Sunfish


The Mola mola—which looks like a prehistoric shark that lost a tail in an epic battle—might be the world's weirdest fish. Here are just a few reasons it's the most fascinating marine creature around.

1. They love to sunbathe.

Sunfish spend up to half the day basking in the sun near the surface of the water, which helps warm their bodies up after deep water dives to hunt.

2. They can weigh more than a car.

The average ocean sunfish is 10 feet long and weighs 2200 pounds, but the biggest can grow up to 5000 pounds. The average pickup truck is only 4000. This makes them the world's largest bony fish.  

3. They lay more eggs than any other animal. 

Image Credit: Pline via Wikimedia Commons // Public Domain

Sunfish can lay up to 300,000,000 eggs at one time, more than any other vertebrate.

4. They have super weird teeth.

Mola mola teeth are fused together in two plates that look like a parrot’s beak

5. They are related to the bass. 

Largemouth bass, smallmouth bass, rock bass, and black bass are all members of the sunfish family. Bass generally eat the smaller members of the sunfish family, like bluegills

6. Eating them is bad luck, according to Polynesian legend. 

A 3500 pound sunfish caught off the coast of California in 1910. Image Credit: Library of Congress via Wikimedia Commons // Public Domain

According to marine biologist Tierney Thys’ site, Polynesians called the sunfish “King of Mackerel.” It was considered bad luck to kill sunfish, lest their loss prevent mackerel from making their way to the islands. 

7. They’re named after a millstone.

The name Mola mola comes from the Latin word for “millstone.” It’s named for its gray, round body, and rough texture. 

8. In German, they are called "swimming heads."  

The German term for a sunfish is Schwimmender Kopf, meaning “swimming head,” a pretty apt description of their appearance. The Polish name for sunfish is samogłów, or “head alone.”

9. They are the namesake of the world’s most popular sailboat. 

The Sunfish, first developed in the late 1950s, was designed to be something like a surfboard with a sail on it. In 1995, it was inducted into the the American Sailboat Hall of Fame as the most popular fiberglass boat ever sold. 

10. They can dive up to 2600 feet. 

A sunfish spotted near the Galápagos. Image Credit: Edgard Dias Magalhães via Wikimedia Commons // CC BY-SA 3.0 

Sunfish generally hang out at depths of 160 to 650 feet, but they can dive much deeper on occasion. In one study, scientists recorded a sunfish diving more than 2600 feet below the surface. 

11. They’re voracious predators. 

Scientists used to think that sunfish were relatively inactive, spending their days sunbathing and feeding on jellyfish. However, despite their doofy appearance, sunfish are active predators with discerning tastes who travel several miles per day. In a recent study, scientists observed sunfish feeding solely on the most energy-rich parts of jellyfish—the gonads and the arms (yum!)—while leaving the less nutritious bell behind. They also occasionally eat small fish and zooplankton. 

12. They were an acceptable form of tax payment in 17th century Japan …

During the 1600s and 1700s, Japanese shoguns accepted Mola mola as payment for taxes [PDF]. 

13. … And are currently the subject of a popular Japanese video game. 

Image Credit: Select Button Inc. via Google Play

A mobile game called Survive! Mola Mola! has more than 6 million downloads in Japan. It revolves around nurturing an ocean sunfish, like Tamagotchi for weird-shaped marine life. 

14. They may or may not be plankton. 

Despite its massive size, the sunfish has been classified for years as a type of plankton, because it seemed to drift with the current rather than swim. (Plankton drift up and down the water column with the current, unable to swim against it.) However, more recent studies of Mola mola have refuted the idea that sunfish are passive planktonic creatures. Tracking has shown that they can move independently of the current, and can swim at speeds similar to that of other large fish

NUS Environmental Research Institute, Subnero
Researchers in Singapore Deploy Robot Swans to Test Water Quality
NUS Environmental Research Institute, Subnero
NUS Environmental Research Institute, Subnero

There's something peculiar about the new swans floating around reservoirs in Singapore. They drift across the water like normal birds, but upon closer inspection, onlookers will find they're not birds at all: They're cleverly disguised robots designed to test the quality of the city's water.

As Dezeen reports, the high-tech waterfowl, dubbed NUSwan (New Smart Water Assessment Network), are the work of researchers at the National University of Singapore [PDF]. The team invented the devices as a way to tackle the challenges of maintaining an urban water source. "Water bodies are exposed to varying sources of pollutants from urban run-offs and industries," they write in a statement. "Several methods and protocols in monitoring pollutants are already in place. However, the boundaries of extensive assessment for the water bodies are limited by labor intensive and resource exhaustive methods."

By building water assessment technology into a plastic swan, they're able to analyze the quality of the reservoirs cheaply and discreetly. Sensors on the robots' undersides measure factors like dissolved oxygen and chlorophyll levels. The swans wirelessly transmit whatever data they collect to the command center on land, and based on what they send, human pilots can remotely tweak the robots' performance in real time. The hope is that the simple, adaptable technology will allow researchers to take smarter samples and better understand the impact of the reservoir's micro-ecosystem on water quality.

Man placing robotic swan in water.
NUS Environmental Research Institute, Subnero

This isn't the first time humans have used robots disguised as animals as tools for studying nature. Check out this clip from the BBC series Spy in the Wild for an idea of just how realistic these robots can get.

[h/t Dezeen]

There May Be an Ancient Reason Why Your Dog Eats Poop

Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]


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