11 Facts About Tiger Sharks

iStock
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.

9 Tiny Facts About the Chevrotain

Dave Curtis, Flickr // CC BY-NC-ND 2.0
Dave Curtis, Flickr // CC BY-NC-ND 2.0

With a round body, spindly legs, and long fangs, this odd creature gives the platypus a run for its money. Also known as the mouse deer, chevrotains are shy and mysterious, and not much is known about them. But here's what we do know.

1. Chevrotains are not mice, nor are they deer.

Lesser mouse deer or chevrotain
BirdHunter591/iStock via Getty Images

At first glance, these animals look like a weird mash-up of a deer, a mouse, and a pig. Mouse deer share a suborder with deer (Ruminantia) but are not considered “true deer.” They have their own family, Tragulidae.

2. Chevrotain species vary by weight.

Mouse deer in Thailand
MonthiraYodtiwong/iStock via Getty Images

These creatures are way smaller than any deer. Depending on the species, a chevrotain can weigh anywhere from 4 to 33 pounds. The smallest species is the lesser Malay, while the largest is the water chevrotain. No species gets any larger than a small dog.

3. There are a lot of different kinds of chevrotains.

Mouse deer
aee_werawan/iStock via Getty Images

This tiny animal comes in many variations. The family has been classified into two genera: true chevrotains (Hyemoschus) and the mouse deer (Tragulus). The spotted mouse deer are still very mysterious, so scientists have placed them in their own genus called Moschiola. Despite being categorized in different genera, they all share a similar look.

4. Chevrotain fangs are fiercer than Dracula's.

Chevrotain in a woodland
BirdHunter591/iStock via Getty Images

Open up a chevrotain’s mouth and you’ll find two long fangs. They're especially elongated in males, which use the needle-like canines to stab each other. Thanks to an extra thick coat and robust muscles around the neck and rump, these adorable fighters are protected from bites during combat.

5. Some consider the chevrotain a living fossil.

Chevrotain sticking its tongue out
Josh More, Flickr // CC BY-NC-ND 2.0

Chevrotains are the most primitive of ruminants. Like deer and similar hoofed animals, they have even-toed hooves and a multi-chambered stomach. But unlike deer, chevrotains have a three-chambered stomach instead of four, and they lack horns or antlers. They haven't changed or evolved much during their time on Earth. Scientists see them as an evolutionary link between ruminants and non-ruminants.

6. Taking a dip is the water chevrotain's best defense.

The water chevrotain is known for its ability to dive underwater when it senses a predator nearby. The miniature swimmers scrunch up and walk on the bottom of rivers and streams to prevent being picked up by the current. If there are any reeds or plants around, the animals will grab them to stay tethered. Chevrotains are able to hold their breath for about four minutes.

While hiding from hungry predators, the water chevrotain can reemerge to get some air before diving back down. Still, the animal tires easily, and can only swim for short periods of time.

7. Childbirth is an expedited experience for chevrotains.

Chevrotain in a woodland
aee_werawan/iStock via Getty Images

After getting pregnant, a female chevrotain will carry the offspring for five to nine months, depending on the species. The baby can usually stand on its own within one hour of being born. Mothers will visit their young periodically for feedings and stand on three legs while nursing.

Chevrotains are known for their ability to be almost continuously pregnant—greater and lesser Malay mouse deer can mate again only a few hours after giving birth.

8. Chevrotains are shy wallflowers.

Chevrotain in a woodland
cowboy5437/iStock via Getty Images

Due to their small size, chevrotains are preyed upon by many different animals. Lacking antlers or horns for protection, the tiny animals are forced to lead secluded lives. Some species are nocturnal and very rarely seen. Chevrotains are very shy and often graze alone, only coming together to mate. They communicate with a series of smells and noises; this timid behavior makes it difficult for scientists to study them.

9. Chevrotain hooves make a lot of noise.

Chevrotain in a woodland
asxsoonxas/iStock via Getty Images

Although normally peaceful, a male will angrily beat his hooves when agitated—they can stomp around four to seven times a second. This “drum roll” technique wards off predators and warns other chevrotains in the area that there’s danger.

Additional sources: "Water Chevrotain," Amazing Animals of the World; "Chevrotains (Tragulidae)," Grzimek's Animal Life Encyclopedia; Mammals IV, Gale Virtual Reference Library

'Lost Species' of Tiny, Rabbit-Sized Deer Photographed in Vietnam for the First Time in 30 Years

Global Wildlife Conservation
Global Wildlife Conservation

The silver-backed chevrotain, also called the Vietnamese mouse-deer, is elusive. It's so elusive that scientists had feared it was extinct after none had been photographed for decades. But as The Washington Post reports, the first images taken of the mammal in nearly 30 years prove that the species is still alive in the woods of Vietnam.

No larger than small dogs, chevrotains are the tiniest ungulates, or hoofed animals, on Earth. They have vampire-like fangs and skinny legs that support their bodies. Silver-backed chevrotains are characterized by the silver sheen of their tawny coat.

The tiny population native to Vietnam has been devastated by poachers in recent decades. That, and the animal's natural shyness, make it incredibly difficult to study. Before this most recent sighting, the last time scientists had recorded one was in 1990.

Global Wildlife Conservation, the Southern Institute of Ecology, and the Leibniz Institute for Zoo and Wildlife Research teamed up in hopes of documenting the lost species. Researchers interviewed residents and government forest rangers in the Vietnamese city of Nha Trang about the silver-backed chevrotain, looking for tips on where to find one. Residents said that while populations had been hit hard by hunting, the animals were still around.

Based on this local ecological knowledge, scientists set up three camera traps in the Vietnamese woods. In just five months, they captured 275 photographs of the little mouse-deer. They then installed 29 additional cameras and snapped 1881 new images in that same length of time.

“For so long this species has seemingly only existed as part of our imagination," Global Wildlife Conservation associate conservation scientist An Nguyen said in a statement. "Discovering that it is, indeed, still out there, is the first step in ensuring we don’t lose it again, and we’re moving quickly now to figure out how best to protect it.”

Now that a silver-backed chevrotain population has been located, researchers plan to conduct the first-ever comprehensive survey of the species. Once the data is collected, it will be used to build a plan for the species' survival.

[h/t The Washington Post]

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