11 Facts About Tiger Sharks

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iStock

Weighing 1300 pounds or more and growing up to 15 feet, the tiger shark is the fourth-largest shark on earth. (Only whale sharks, basking sharks, and great whites get bigger.) On top of being big, tiger sharks are also pretty bizarre: They literally eat garbage, give birth to massive litters—and one of them was a player in Australia’s greatest unsolved murder mystery.

1. THEY’RE LIKE SWIMMING GARBAGE DISPOSALS.

Tiger sharks have broad diets: They eat everything from albatrosses, venomous sea snakes, and other sharks to manmade objects like paint cans, leather jackets, rubber tires, and even license plates. (That scene in Jaws where Hooper pulls a Louisiana plate from the stomach of a dead tiger shark is scientifically accurate!)

2. DON’T CONFUSE THEM WITH SAND TIGER SHARKS.

You might assume that the tiger shark (Galeocerdo cuvier) and the sand tiger shark (Carcharias taurus) are cousins, but the latter is more closely related to the great white (Carcharodon carcharias) than it is to the tiger shark.

3. NOT ALL OF THEM HAVE STRIPES.

Hear the word tiger and you think vertical stripes, but those stripes evolve over time. Baby tiger sharks—a.k.a. pups—are covered in roundish gray spots that fuse into stripes as the sharks mature. After a certain age, the stripes start to fade; they’re barely visible in full-grown adults.

4. TIGER SHARKS PREFER WARM WATER.

Tiger sharks are seen in tropical to warm temperate waters all over the world, and a study published in Global Change Biology in March 2018 revealed that the sharks have a "Goldilocks" zone. “Our study suggests that 22 degrees [Celsius, 71.6 degrees Fahrenheit] is not too cold for the animals and it’s not too hot for them,” lead author Nicholas Payne told the BBC. “It’s about right in terms of their optimal preference for temperature.” The scientists reached that conclusion after monitoring tagged sharks near Hawaii and comparing those findings to several decades’ worth of Australian fishing records.

5. THEY HAVE NOTCHED TEETH.

the teeth of the tiger shark with serrated edges

If you could pry open a tiger shark’s jaws, you’d see teeth with dramatic notch tips that point sideways. You'd also notice that the teeth on the left and right halves look like mirror images of each other. A tiger shark’s teeth have a dual function: They help the fish grasp onto struggling victims and can shear right through the thickest of hides, making them well-equipped to go after just about any prey that’s available.

6. THEY MIGHT BE THE ONLY SHARKS TO REGULARLY HUNT SEA TURTLES.

Every year, 12,000 nesting sea turtles visit Raine Island in the Great Barrier Reef, and tiger sharks—which hunt the turtles—aren't far behind.

To get its meal, the shark first has to get a good grip, but the turtle doesn't make it easy: When a shark gets too close for comfort, a turtle may respond by turning itself sideways so the top of the carapace is perpendicular to the shark’s jaws, making themselves too wide to bite into. Turtles in this position will also swim in tight circles around the predator, which protects the reptile’s vulnerable flanks.

According to a 2016 study, the sharks tend to avoid healthy turtles and instead conserve energy by going after sick or dying (or dead) turtles.

7. SEA GRASS SEEMS TO BENEFIT WHEN TIGER SHARKS ARE AROUND.

Though Australia's Shark Bay is home to a diverse array of organisms, it got its moniker for the 28 shark species that have been seen there—including tigers, which are especially common.

Sea grasses are the backbone of Shark Bay's ecosystem; they provide shelter for small animals and food for big herbivores. But the grasses were decimated after a 2011 heat wave. Since then, they've been making a gradual comeback, and scientists have noticed that they grow at a higher rate in places frequented by tiger sharks. This is probably because the sharks frighten off sea turtles and dugongs who like to eat the grass. “Just the fear of sharks can be enough, in many cases, to keep a marine ecosystem healthy and able to respond to stresses,” biologist Michael Heithaus said in a news release.

8. TIGER SHARKS GIVE BIRTH TO HUGE LITTERS.

Female tiger sharks are pregnant for 14 to 16 months and give birth to at least 10 pups, with around 30 being the average. But sometimes, they have many, many more than that: There have been reports of females birthing 80 pups at once. Usually, newborns weigh between six and 13 pounds.

9. IN THE ATLANTIC, THEY MIGRATE SOUTH FOR THE WINTER.

There's still a lot to learn about the travel habits of tiger sharks. A seven-year study found that Hawaiian females tend to travel more often—and more widely—around the island chain than males do. Another analysis, published in 2015 in Scientific Reports, focused on 24 adult tiger sharks in the Atlantic and found that, in the winter months, they stayed in the area around the Caribbean and West Indies. Then, for summer, they headed north and spent the warmest part of the year in the mid-Atlantic, venturing as far north as Connecticut (and far away from the coast). No one knows why the sharks make the trip, but it may have something to do with the young loggerhead turtles who dwell in those northern waters.

10. ONE TIGER SHARK BARFED UP A MURDER MYSTERY.

In April 1935, Coogee Aquarium in Sydney, Australia was looking for a big fish to occupy its newly-built pool. On a fishing trip off Coogee beach, Bert Hobson snared a 13-foot tiger shark for the aquarium.

The shark was a big hit at the aquarium, but it didn’t last very long. Seven days after its arrival, it got sick and vomited up a bird, a rat, some nasty-looking brown goo—and a human arm, which had a rope tied around its wrist and a forearm tattoo of two boxers.

An amateur boxer named James Smith had recently gone missing, and he had the exact same tattoo on one arm. Forensic analysis determined that the arm hadn’t been bitten off—it had been removed from the rest of Smith's body with a knife.

Detectives learned that Smith was last seen playing cards at the Hotel Cecil in Cronulla with his longtime associate Patrick Brady, a forger, who quickly became the number one suspect. The authorities were later informed by a boat-builder (and suspected criminal) named Reginald Holmes that Brady had murdered Smith in an argument. But before Holmes could testify in court, somebody shot him.

Brady's lawyers argued that a severed arm didn’t constitute proof of a murder. Smith, they argued, might still be alive somewhere—sans one limb, of course. Brady got off scot-free, which was more than could be said for the poor tiger shark—it died in captivity. A necropsy did not reveal any other human remains.

11. IT’S RARE, BUT TIGER SHARKS HAVE BEEN KNOWN TO SHARE FOOD WITH CROCODILES AND GREAT WHITES.

Bloated, rotting whale carcasses lure all kinds of animals out of the woodwork. Carnivores that normally don’t cross paths sometimes end up feasting on the dead mammals side-by-side. In 2015, two great whites and three tiger sharks were filmed tearing into the colossal body of a sperm whale near New South Wales, Australia. Years earlier, off the South African coastline, witnesses saw members of both species eating a Byrd’s whale carcass [PDF]. Australian drone footage from 2017 (above) shows a humpback carcass getting picked apart by both tiger sharks and saltwater crocodiles. Look at the video closely and you’ll see the croc and fish coming within a few yards of each other.

10 Products for a Better Night's Sleep

Amazon/Comfort Spaces
Amazon/Comfort Spaces

Getting a full eight hours of sleep can be tough these days. If you’re having trouble catching enough Zzzs, consider giving these highly rated and recommended products a try.

1. Everlasting Comfort Pure Memory Foam Knee Pillow; $25

Everlasting Comfort Knee Pillow
Everlasting Comfort/Amazon

For side sleepers, keeping the spine, hips, and legs aligned is key to a good night’s rest—and a pain-free morning after. Everlasting Comfort’s memory foam knee pillow is ergonomically designed to fit between the knees or thighs to ensure proper alignment. One simple but game-changing feature is the removable strap, which you can fasten around one leg; this keeps the pillow in place even as you roll at night, meaning you don’t have to wake up to adjust it (or pick it up from your floor). Reviewers call the pillow “life-changing” and “the best knee pillow I’ve found.” Plus, it comes with two pairs of ear plugs.

Buy it: Amazon

2. Letsfit White Noise Machine; $21

Letsfit White Noise Machine
Letsfit/Amazon

White noise machines: They’re not just for babies! This Letsfit model—which is rated 4.7 out of five with nearly 3500 reviews—has 14 potential sleep soundtracks, including three white noise tracks, to better block out everything from sirens to birds that chirp enthusiastically at dawn (although there’s also a birds track, if that’s your thing). It also has a timer function and a night light.

Buy it: Amazon

3. ECLIPSE Blackout Curtains; $16

Eclipse Black Out Curtains
Eclipse/Amazon

According to the National Sleep Foundation, too much light in a room when you’re trying to snooze is a recipe for sleep disaster. These understated polyester curtains from ECLIPSE block 99 percent of light and reduce noise—plus, they’ll help you save on energy costs. "Our neighbor leaves their backyard light on all night with what I can only guess is the same kind of bulb they use on a train headlight. It shines across their yard, through ours, straight at our bedroom window," one Amazon reviewer who purchased the curtains in black wrote. "These drapes block the light completely."

Buy it: Amazon

4. JALL Wake Up Light Sunrise Alarm Clock; $38

JALL Wake Up Light Sunrise Alarm Clock
JALL/Amazon

Being jarred awake by a blaring alarm clock can set the wrong mood for the rest of your day. Wake up in a more pleasant way with this clock, which gradually lights up between 10 percent and 100 percent in the 30 minutes before your alarm. You can choose between seven different colors and several natural sounds as well as a regular alarm beep, but why would you ever use that? “Since getting this clock my sleep has been much better,” one reviewer reported. “I wake up not feeling tired but refreshed.”

Buy it: Amazon

5. Philips SmartSleep Wake-Up Light; $200

Philips SmartSleep Wake-Up Light
Philips/Amazon

If you’re looking for an alarm clock with even more features, Philips’s SmartSleep Wake-Up Light is smartphone-enabled and equipped with an AmbiTrack sensor, which tracks things like bedroom temperature, humidity, and light levels, then gives recommendations for how you can get a better night’s rest.

Buy it: Amazon

6. Slumber Cloud Stratus Sheet Set; $159

Stratus sheets from Slumber Cloud.
Slumber Cloud

Being too hot or too cold can kill a good night’s sleep. The Good Housekeeping Institute rated these sheets—which are made with Outlast fibers engineered by NASA—as 2020’s best temperature-regulating sheets.

Buy it: SlumberCloud

7. Comfort Space Coolmax Sheet Set; $29-$40

Comfort Spaces Coolmax Sheets
Comfort Spaces/Amazon

If $159 sheets are out of your price range, the GHI recommends these sheets from Comfort Spaces, which are made with moisture-wicking Coolmax microfiber. Depending on the size you need, they range in price from $29 to $40.

Buy it: Amazon

8. Coop Home Goods Eden Memory Foam Pillow; $80

Coop Eden Pillow
Coop Home Goods/Amazon

This pillow—which has a 4.5-star rating on Amazon—is filled with memory foam scraps and microfiber, and comes with an extra half-pound of fill so you can add, or subtract, the amount in the pillow for ultimate comfort. As a bonus, the pillows are hypoallergenic, mite-resistant, and washable.

Buy it: Amazon

9. Baloo Weighted Blanket; $149-$169

Baloo Weighted Blanket
Baloo/Amazon

Though the science is still out on weighted blankets, some people swear by them. Wirecutter named this Baloo blanket the best, not in small part because, unlike many weighted blankets, it’s machine-washable and -dryable. It’s currently available in 12-pound ($149) twin size and 20-pound ($169) queen size. It’s rated 4.7 out of five stars on Amazon, with one reviewer reporting that “when it's spread out over you it just feels like a comfy, snuggly hug for your whole body … I've found it super relaxing for falling asleep the last few nights, and it looks nice on the end of the bed, too.” 

Buy it: Amazon 

10. Philips Smartsleep Snoring Relief Band; $200

Philips SmartSleep Snoring Relief Band
Philips/Amazon

Few things can disturb your slumber—and that of the ones you love—like loudly sawing logs. Philips’s Smartsleep Snoring Relief Band is designed for people who snore when they’re sleeping on their backs, and according to the company, 86 percent of people who used the band reported reduced snoring after a month. The device wraps around the torso and is equipped with a sensor that delivers vibrations if it detects you moving to sleep on your back; those vibrations stop when you roll onto your side. The next day, you can see how many hours you spent in bed, how many of those hours you spent on your back, and your response rate to the vibrations. The sensor has an algorithm that notes your response rate and tweaks the intensity of vibrations based on that. “This device works exactly as advertised,” one Amazon reviewer wrote. “I’d say it’s perfect.”

Buy it: Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

31 Facts About Sharks

Photo by Jakob Owens on Unsplash
Photo by Jakob Owens on Unsplash

Whether you're a Jaws fanatic or just want to live every week like it's Shark Week, you'll want to read up on these fascinating facts about sharks, adapted from an episode of The List Show on YouTube.

1. There are more than 500 types of sharks.

They range in size from 8 inches to 40 feet long.

2. The cookie cutter shark grows to up to 22 inches.

The cookie cutter shark uses its suction-cup-like lips to attach itself to prey. Once it’s firmly stuck on there, the shark spins its body, using its bottom row of serrated teeth to take out a cone-shaped chunk of flesh. Typically, cookie cutters feed off of sea creatures much bigger than them, but they’ve also taken bites out of a couple of humans … and they’ve been known to leave their mark on submarines, too.

3. Peter Benchley’s 1974 novel Jaws was inspired by a fisherman who caught a 4500-pound behemoth in Montauk in 1964.

The novel wasn’t always going to be called Jaws: Alternate titles included “The Stillness in the Water,” “The Silence of the Deep,” “Leviathan Rising,” and “The Jaws of Death."

4. Peter Benchley later became a shark conservationist.

He used his pen to tackle misconceptions about the fish. In 2006, he said, “I could never write that book today. Sharks don’t target human beings and they certainly don’t hold grudges.” Fun fact: Benchley makes a cameo in Steven Spielberg’s 1975 movie adaptation of his novel. He plays a TV news reporter.

5. Shark attacks are very rare.

In 2018, there were 66 confirmed unprovoked attacks. In America, the risk of dying from a shark attack is 1 in 3,748,067. You’re more likely to be killed by fireworks, a train crash, or MRSA—that antibiotic-resistant bacteria—than you are by sharks. Worldwide, the risk is even lower.

6. Sharks have been around for a while.

Thanks to fossils, we know that they’ve been swimming the seas for at least 400 million years.

7. Some species of shark can live to be incredibly old.

Researchers in 2016 used radiocarbon dating on the eyes of 28 Greenland sharks and determined that one female might have been around 400 years old.

8. Greenland shark meat is a delicacy in Iceland called hákarl.

The shark’s meat is toxic when fresh, so it has to go through a fermentation process that involves burying the shark’s body in sand under rocks for six to 12 weeks. The meat is then cut up and hung to dry. The finished product has a strong scent of ammonia. Anthony Bourdain called it "the single worst, most disgusting and terrible tasting thing" he’d ever eaten.

9. Great white sharks have a man-eating reputation, but they’re much more interested in seals and sea lions.

Great whites have a 40 to 55 percent accuracy rate in catching their seal prey, according to research. The hunting process also often involves the sharks coming fully out of the water, which is called breaching.

10. Great whites are fast.

They can swim at 35mph for short bursts.

11. Many shark researchers think the old tale of “great whites attack humans because they think we’re seals” is a myth.

Great white shark attacks on humans are much less vicious than the way sharks attack prey like seals and sea lions—one study reported that in 76 percent of attacks on surfers the force would not have stunned a pinniped. In most cases they’re probably just curious—though still potentially deadly. One expert told Discovery that if you do see a shark, the safest thing to do is to remain calm and try to slowly and calmly get back to safety.

12. Great white sharks typically aren’t found in aquariums—though not for lack of trying.

Since the 1970s, aquarium workers who have tried to keep the sharks in captivity have been having basically the same tragic experience: finding a captive great white shark sick, then dead, within a week. While in enclosures, the sharks can't swim at the high speeds or over the distances they're supposed to, so they bump into the glass and get hurt or just stop swimming and die. Younger sharks have tended to do better: The Monterey Bay Aquarium was able to keep a young great white for 198 days, but released her after she started going after other sharks.

13. Tiger sharks and sand tiger sharks aren't the same.

Another shark you probably won’t see in captivity these days is the tiger shark—not to be confused with the sand tiger shark, which is a completely different species found in aquariums around the world.

14. Female tiger sharks have many, many pups.

After 13 to 16 months of pregnancy, a female might give birth to between 10 and 82 little shark babies. The average is around 30.

15. It’s not unusual for a female shark to give birth to her pups in the place where she herself was born.

One study, which began in 1995 and concluded in 2012, found this to be the case with lemon sharks in the Bahamas.

16. Female mako sharks stay away from male makos.

In research that lasted for four months, a biologist and his team recorded 264 male and 132 female mako sharks in the Easter Island area. They found that there was a clear divide between where males resided versus females. They were baffled as to why. One of them suggested that it might have to do with the fact that males often bite their intended mate, so maybe the females were trying to avoid that whole situation. Fun fact: Biting is often a part of shark copulation, because the males have to hang on to something.

17. It’s not just biologists who have taken an interest in sharks.

In 2002, software programmer Jason Holmberg went scuba diving on vacation and spotted the rare whale shark. He wanted to make the spotted sharks less mysterious, so he teamed up with an astrophysicist and a marine biologist. They were able to adapt an algorithm that had been created for the Hubble Space Telescope program and use it to start identifying sharks. The algorithm was initially for star mapping, so it made sense as an algorithm for shark spot mapping. They’ve since created a database with 32,000 pictures of whale sharks. The database has helped them track the animals’ locations, which means they can learn more about the whale shark lifestyle.

18. The shape of hammerhead sharks' heads might help with hunting.

Sharks are able to sense electric fields in water, which allows them to determine if they’re in the vicinity of prey. One theory is that hammerhead sharks have more of those sensory organs in their heads, so they can find prey better. Their eyes being so far apart helps too—they have better binocular vision.

19. Shark embryos can sense predators.

In addition to using electric fields to sense prey, sharks also use them to sense predators. Even shark embryos have that ability. In a study published in 2013, a group studying brownbanded bamboo shark embryos found that when the embryos were in the electric field of a predator, their gills would stop moving.

20. Sharks sometimes like to rest in groups.

Nurse sharks and whitetip reef sharks have been observed gathering in groups of 2 to 40, usually in a safe place like a crevice, often just napping.

21. A basking shark looks very weird when it decomposes.

It quickly loses parts of its jaw and tail. So it’s not unusual for people who spot a decomposing basking shark on the shore to believe that they’ve found a sea monster. This happened in 1970 in Massachusetts.

22. A tiger shark once puked up evidence of a murder.

During the 1930s, a tiger shark at Coogee Aquarium in Australia vomited a human arm, evidence that became part of a murder trial. Thanks to a tattoo on the arm, the person it belonged to, James Smith, was identified. It turned out that he was missing—and the shark hadn’t bitten the arm off, it was cut off with a knife. There was a suspect, Patrick Brady, and a man willing to testify that Brady was responsible. But that witness was shot before the trial. Brady’s lawyer claimed that for a homicide, there needed to be a body and all they had was an arm. Brady went free. The shark unfortunately died.

23. The goblin shark eats using "slingshot feeding."

The deep-sea-dwelling goblin shark has a jaw that shoots outward to grab prey in what scientists have dubbed “slingshot feeding,” so it’s no wonder they often get compared to monsters. The goblin shark can deploy its jaw at 10.1 feet per second—roughly twice the speed that New York City pedestrians walk.

24. The goblin shark is named after a Japanese demon.

Japanese fishermen named the sharks tengu-zame. Tengu is a demon with a long nose that sometimes steals children. And zame means “shark.” That’s how we got our English translation: goblin shark.

25. Not all sharks are ferocious carnivores.

The bonnethead shark has long been observed to eat seagrass—up to 62.1 percent of gut content mass. Until recently it was unclear if they were digesting it. But in 2018 it was confirmed through stable isotope analysis that they actually were, making them the first known omnivorous shark.

26. There are multiple types of lantern sharks, including a dwarf lantern shark that doesn’t grow larger than 8 inches.

These sharks have bellies and fins that glow. So it’s thought that when there’s a predator swimming beneath them, the predator doesn’t know the difference between the shark and the light coming into the ocean from the sun.

27. Not all sharks are strictly ocean dwellers.

Bull sharks are unusual in that they can tolerate fresh water. Most sharks have to be in salt water because that’s what their bodies can handle—put them in fresh water and they’ll lose too much salt. But bull sharks are better able to retain salt in their bodies, so they can travel in fresh water. And in fact, in 1937, one was caught in Alton, Illinois, 1000 miles up the Mississippi River from the Gulf of Mexico, where you wouldn’t typically expect to encounter a shark.

28. Megalodon sharks were huge—maybe about 50 feet long.

But there are now theories that the measly great white shark, at less than half that size, may have caused them to go extinct. It was previously believed that megalodons went extinct around 2.6 million years ago, but when a group of paleontologists and geologists went back through the fossils and data, they pegged it at 3.6 million years ago—which just so happened to be the time that great white sharks were emerging. They were probably able to go head-to-head with younger megalodons and out-compete them for food.

29. Megalodon shark teeth could be around 7 inches long.

And in fact, you might want to be on the lookout for them. In 2018, a couple found a fossilized megalodon tooth on a beach in North Carolina.

30. An American president had a megalodon tooth.

Thomas Jefferson loved fossils and even kept some on display at the entrance of Monticello. Today, his megalodon tooth is at the Academy of Natural Sciences in Philadelphia. Of course, he signed it.

31. The song "Baby Shark" used to be sung by kids at camps.

Before Pinkfong’s version of “Baby Shark” became one of the most viewed YouTube videos of all time, it was a common song for kids to sing at camps. But when Johnny Only turned it into the bop that we all get stuck in our heads today, he did change some things. In the original lyrics, the sharks attack people and even kill them. Peter Benchley would not approve.