15 Delightful Facts About Dolphins

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iStock

Dolphins are known for being smart, playful creatures that can learn to perform impressive tricks. But you might not know that dolphins are also champion nappers who have helped the U.S. Navy protect nuclear warheads. We're celebrating National Dolphin Day with these 15 facts about the cute, friendly cetaceans.

1. THEY'RE EXCELLENT NAPPERS.

Since dolphins can't breathe underwater, they need to swim up to the ocean's surface to get air. So how do they sleep without drowning? Essentially, dolphins are champion power nappers. Rather than sleep for several hours at a time, they rest one hemisphere of their brain for 15 to 20 minutes at a time, and they take these "naps" several times each day. By resting one hemisphere of their brain at a time, dolphins can continue swimming, breathing, and watching for predators 24/7.

2. THEY COMMUNICATE WITH CLICKS AND WHISTLES …

dolphins underwater
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Dolphins communicate with one another underwater by making a variety of vocalizations. To find prey and navigate the ocean, they make clicking sounds, and they "speak" to other dolphins by whistling. Dolphins also produce loud burst-pulse sounds when they feel excited or aggressive, such as when they need to scare off a nearby shark. Some female dolphins also produce a burst-pulse to reprimand their offspring, called calves, for bad behavior.

3. … BUT THEIR LANGUAGE REMAINS A MYSTERY.

Although marine scientists have studied and recorded dolphin vocalizations for decades, many aspects of the animals’ language and how they communicate are still unknown. Scientists have not yet broken down the individual units of dolphin sounds, and they're still searching for a Rosetta Stone that links the animals' vocalizations to their behavior. By using new technologies—including algorithms and high-frequency recorders that work underwater—scientists hope to finally unlock the mystery of the dolphin language.

4. THEY USE ECHOLOCATION TO NAVIGATE.

To know where they are in relation to other objects and animals, dolphins use echolocation (a.k.a. biological sonar). After emitting a series of high-pitched clicks, they listen for the echoes to bounce off their surroundings. Based on these echoes, dolphins can judge where they are in space and determine the size and shape of nearby objects. Besides helping dolphins evade predators, echolocation allows them to trap, catch, and eat fish and squid.

5. THEY MAKE FRIENDS WITH OTHER DOLPHINS …

spotted dolphins swimming
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Dolphins are highly social, and scientists are still discovering fascinating details about how the aquatic mammals socialize with one another. In 2015, scientists at Florida Atlantic University's Harbor Branch Oceanographic Institute published research in the Marine Mammal Science journal about the social networks of dolphins. After spending over six years tracking 200 bottlenose dolphins in Florida's Indian River Lagoon, the scientists discovered that dolphins have friends. Instead of spending equal time with the dolphins around them, the animals actually segregate themselves into friend groups. Just like humans, dolphins seem to prefer the company of certain peers more than others.

6. … AND EACH DOLPHIN RESPONDS TO ITS OWN NAME.

Dolphins aren't swimming around with name tags, but every dolphin has its own unique whistle. Scientists believe that dolphins use these signature whistles for life, and female dolphins may even teach their calves their whistles before they're born. Dolphins use their signature whistles to call out to one another and may be able to remember other dolphins' whistles after decades apart.

7. THERE ARE 44 DIFFERENT DOLPHIN SPECIES.

an orca jumping out of the water
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Although bottlenose dolphins are the most well-known and recognizable, there are 43 other dolphin species. Most species live in temperate and tropical oceans, but a few live in colder oceans or rivers. Depending on their species, dolphins can vary considerably in their physical attributes and behavior. For example, the largest dolphin species, the Orca (also called Killer Whale), can be 30 feet long—10 times longer than the smallest dolphins.

8. THEY DON'T USE THEIR TEETH TO CHEW FOOD.

two smiling dolphins
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Dolphins have teeth, but they don't use their chompers to chew food. Instead, dolphins use their teeth to catch prey (fish, crustaceans, and squid) and swallow it whole. Since they forgo chewing, digestion occurs in their stomach—or, more precisely, in part of their stomach. Dolphins have multiple stomach chambers, one of which is devoted to digestion, while the other chambers store food before it's digested.

9. THEY TYPICALLY GIVE BIRTH TO JUST ONE CALF.

mother and baby dolphin
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Depending on their species, most female dolphins (called cows) carry their babies for nine to 17 months before giving birth to a calf. Interestingly, calves are born tail first, rather than head first, so they don't drown during the birthing process. After nursing for one to two years, a calf typically stays with its mother for the next one to seven years, before mating and having its own calves.

10. THEIR SKIN CAN BE REGENERATED EVERY TWO HOURS.

If you've ever swum with dolphins, you know their skin looks and feels super smooth and sleek. There's a reason for that—a dolphin's epidermis (outer layer of skin) can be sloughed off and replaced with new skin cells as often as every two hours. Because their skin regenerates so often, it stays smooth and, as most scientists believe, reduces drag as they swim.

11. THE U.S. NAVY TRAINS DOLPHINS TO PROTECT NUCLEAR WEAPONS.

A bottlenose dolphin named K-Dog from the Commander Task Unit jumps out of the water in 2003. Commander Task Unit is comprised of special mine clearing teams from The United Kingdom, Australia, and the U.S.
A bottlenose dolphin named K-Dog from the Commander Task Unit jumps out of the water in 2003. Commander Task Unit is comprised of special mine clearing teams from The United Kingdom, Australia, and the U.S.
Brien Aho, U.S. Navy/Getty Images

Despite dolphins' general friendliness, some of them are trained for combat. The Navy Marine Mammal Program at San Diego's Space and Naval Warfare Systems Command (SPAWAR) trains dozens of bottlenose dolphins (as well as sea lions) to help the U.S. Navy. In the past, the U.S. military has used dolphins in conflicts in Vietnam and the Persian Gulf. Today, thanks to their intelligence, speed, and echolocation skills, dolphins are trained to find enemy swimmers, locate underwater mines, and guard nuclear arsenals.

12. THEY'RE NOT THE SAME AS PORPOISES.

To the untrained eye, dolphins and porpoises look nearly identical, and many people mistakenly think that porpoises are a type of dolphin. But the two species belong to completely different families and differ in their physical attributes. So how can you tell them apart? Dolphins, which are usually bigger than porpoises, typically have longer beaks and curved dorsal fins. Porpoises, on the other hand, have more triangular dorsal fins as well as spade-shaped (rather than conical) teeth.

13. HUNTING, OVERFISHING, AND RISING OCEAN TEMPERATURES THREATEN THEM.

Some dolphin species are endangered or functionally extinct (like China's baiji dolphin) due to hunting, overfishing, and pollution. Although dolphin meat is high in mercury, the animals are still hunted for their meat and eaten in parts of Japan and the Faroe Islands of Denmark. Overfishing means that dolphins' food sources are shrinking, and some dolphins get caught up in fishing nets and die. Additionally, climate change and rising ocean temperatures are driving some fish and squid away from their natural habitats, putting dolphins' main food source at risk.

14. A SUPERPOD CAN CONSIST OF MORE THAN 1000 DOLPHINS.

a pod of dolphins swimming
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Dolphins live in groups, called pods, that typically contain dozens or hundreds of dolphins. By swimming in a pod, dolphins work together to hunt prey, evade predators, and care for sick or injured members. But different pods can also merge, forming a superpod of more than 1000 dolphins. Superpods are typically temporary and occur in parts of the ocean with plentiful food (and less competition for tasty squid).

15. THE OLDEST DOLPHIN IN CAPTIVITY LIVED TO 61 YEARS OLD.

Dolphin lifespan varies greatly by species. Most dolphins in the wild live for a few decades, while those in captivity have a drastically reduced lifespan and may live for only a few years. So it's all the more shocking that the oldest dolphin in captivity lived to be a sexagenarian. Nellie, a bottlenose dolphin who lived in a marine entertainment park in Florida, was born in 1953. She appeared on TV shows and commercials and performed tricks for the park's attendees before passing away in 2014.

5 Ways You Can Help the Jaguar Rescue Center Save Costa Rica’s Wildlife

A curious sloth says hello after members of the Jaguar Rescue Center reunited her with her baby.
A curious sloth says hello after members of the Jaguar Rescue Center reunited her with her baby.
Jaguar Rescue Center

In 2005, Catalonian primatologist Encar Garcia and her husband, Italian herpetologist Sandro Alviani, were living in southwestern Costa Rica when locals began to bring them injured animals in hopes that the two experts could save them. As word spread and more animals arrived, their property slowly transformed into a full-fledged rescue center. So they purchased the surrounding land and named their new organization the Jaguar Rescue Center (JRC), after one of their early rescues: a young, orphaned jaguar whose mother had been killed by farmers.

Today, the center covers nearly 5.5 acres of land near Puerto Viejo de Talamanca in Costa Rica’s Limón province. It can accommodate around 160 animals at a time, and is home to everything from spider monkeys to sea turtles (though, by law, staff members aren’t allowed to accept domesticated animals like cats and dogs).

While locals still bring injured and orphaned animals to the JRC, others are brought by tourists, the Ministry of Environment and Energy, the National Animal Health Service, and even the police, who confiscate animals that have been poached or illegally kept as pets.

howler monkey at jaguar rescue center
Skye, a young howler monkey who recovered from electrocution.
Jaguar Rescue Center

The rescues are often victims of road accidents, animal attacks, environmental destruction, human interaction, or electrocution from exposed power lines. After the animals are rehabilitated, they’re released into La Ceiba Natural Reserve, a human-free (except for JRC workers) part of the forest where they can safely reacclimate to living in the wild. The JRC has cameras installed in the area to monitor the animals after their release and make sure they’re finding enough food.

Unfortunately, not all the creatures brought to the JRC recover from their injuries—in 2019, for example, 311 of the 749 rescues died [PDF]—so JRC staff members and volunteers understand just how remarkable it is to watch an animal regain its health and be successfully returned to its natural environment.

“There are so many amazing things about working for the JRC, but I think we all can agree that seeing a rescued animal make it through rehabilitation and be released is the best and most rewarding part of the job,” Torey, a JRC tour guide, tells Mental Floss.

Some thought-to-be-orphaned sloths are even released right back into the arms of their mothers. After recording the cries of a baby sloth, JRC staff will take the sloth back to wherever it was first found, play the recording, and wait for the mother to recognize the cries and (slowly) climb down from her leafy abode to reunite with her child.

Despite its partnerships with government agencies, the JRC doesn’t receive government funding. Instead, it relies on public donations and revenue from its visitor services. Find out more about how you can help below.

1. Donate money.

You can make a one-time or monthly donation that will go toward food, medical care, and supplies for the animals, or you can donate specifically to the JRC’s “Shock Free Zone” program, which insulates power lines and transformers that run through forests to prevent them from electrocuting wildlife.

2. Donate items.

Check out the JRC’s Amazon wish list to see which items are most needed—and what they’ll be used for, too. Examples include Pampers diapers for baby monkeys, snake hooks for safely rescuing snakes, and cans of worms to feed birds, opossums, and bats.

One of the most important products on the list is powdered goat’s milk, which staff members use to feed orphans of many mammalian species at the JRC.

“It has the most universally digestible enzyme compared to other milk,” Torey says. “Unfortunately, we do not have sloth milk, monkey milk, etc. readily available for the baby animals.”

3. “Adopt” an animal.

diavolino, a margay at the jaguar rescue center
Diavolino, the Jaguar Rescue Center's "feisty little margay."
Jaguar Rescue Center

For $105, you can virtually “adopt” an animal at the JRC. Choices range from Diavolino, a “feisty little margay” rescued from the illegal pet trade, to Floqui, a whitish two-fingered sloth who was born with only one digit on each hand and foot.

4. Visit the Jaguar Rescue Center.

You can stay overnight at the JRC in one of its three visitor residences—La Ceiba House, Ilán Ilán House, or one of the Jaguar Inn bungalows—which offer a variety of amenities, restaurant service, and access to nearby beaches.

Whether or not you’re staying there, you can book a tour of the JRC, where you’ll get to explore the premises and even meet some of the animals. There are private, public, nighttime, and VIP tours, and you can find out more here.

5. Volunteer at the Jaguar Rescue Center.

If you’re looking for a more hands-on, potentially life-changing way to help Costa Rica’s wildlife, you can apply for the JRC’s four-week volunteer program or a position at La Ceiba Natural Reserve that lasts three to six months.

According to the website, JRC volunteers are housed in the Jaguar Inn and help with “a broad range of tasks, from doing the dishes and cleaning up after the animals ... to building and remodeling enclosures, or babysitting a new arrival to ease the stress of their new environment.”

La Ceiba volunteers, on the other hand, stay right on the reserve and do everything from monitoring captive and recently released animals to keeping the trails clear.

Find out more about becoming a volunteer here.

YouTube Star Coyote Peterson Brings 'Misunderstood' Animals to His New Animal Planet Series

Animal Planet
Animal Planet

As host of the popular YouTube series Brave Wilderness, Coyote Peterson is no stranger to going face-to-face with creatures many deem terrifying—think great white sharks and pit vipers—but that he says are simply "misunderstood."

Animals have always been a big part of Peterson's life, even before he made a career out of being stung and bitten by ferocious critters. The Ohio native studied video production and directing at Ohio State University, and then decided to combine his two passions—film and all things wild—to teach viewers about wildlife and the importance of conservation. His YouTube channel currently has more than 15 million subscribers.

Now Peterson is embarking on a new adventure with Animal Planet in the show Brave the Wild. He'll travel all over the world with wildlife biologist Mario Aldecoa and his crew, sharing creatures that aren't often in the spotlight and that viewers may find a little frightening. He recently chatted with Mental Floss about the importance of conservation, his thing for snapping turtles, and his close encounter with a jaguar and her three cubs.

You’ve said your love of animals started with snapping turtles. Can you talk about the first time you saw one and what about them fascinated you so much?

The first snapping turtle I caught was when I was only 8 years old. I was always fascinated with turtles, because at first glance they look prehistoric, almost dinosaur-like. Growing up in Ohio, I never got to see any "exotic" animals. My favorite thing to watch on TV was Steve Irwin. Watching him wrestle crocs is what inspired me to catch my first snapping turtle, the most dangerous animal Ohio has to offer.

Coyote Peterson with a gigantic snapping turtle
Animal Planet

In Brave the Wild, you introduce animals that are often feared or misunderstood. What's the importance in exposing viewers to these creatures?

One of my goals through this series was to inspire people to overcome their fears of these seemingly dangerous animals and learn to admire them from a safe distance. The more you understand these creatures, the less you are afraid of them. One of the messages I try to convey in every episode is the importance of conservation.

What’s the most "misunderstood" creature you've encountered?

The most misunderstood creature that comes to mind is the carpet shark, which we filmed in season one. As I always say, people’s biggest fears are the three S’s (sharks, snakes and spiders). The carpet shark is found off the coast of Australia. They only bite humans in the case of mistaken identity. To some of these sharks a person’s foot might look like a fish. Any time you enter a new environment you need to be aware of what you need to look for, not only to keep yourself safe, but the animal as well.

What goes into preparing for each encounter to make sure you and the animals come out alive?

With any new expedition, you need to come into the environment knowing exactly what to expect. When encountering a new animal, I try to stay as calm as I can and have no hesitation. If I stay calm, the animal stays calm, [and] I'm creating a safer interaction for myself. I use different tactics when I encounter different animals. It also depends on whether the environment is land or in water.

How do you keep your composure on camera when you're in a potentially dangerous situation?

Any situation I find myself in, I look at it as my job. For example, I would be afraid operating a crane, because that is something I don't do. If it's part of your job, it's something that you get used to. When I do my job, I make sure I'm focused and never hesitate. Before I encounter any animal, I know what I'm going to say to the camera. I say that, for the best show, we always need to have the camera rolling so the audience can see what is happening.

Coyote Peterson with a kangaroo
Animal Planet

You were in Australia filming Brave the Wild during bushfire season. What was that like?

Visiting Australia was one of the best experiences I had filming the show. Australia is a fascinating country that has so many unique environments. We spent over 50 days in Australia and encountered more than 35 different species. We were there right before all these devastating fires started, and we got to witness the severity of the drought and all the different animals it impacted.

What was your favorite animal encounter in upcoming series?

Each encounter I have in the wild is special. I would have to say that the most exciting moment for me was when we were filming in Brazil and I saw a jaguar and three of her cubs up close. Not only did I get to see this in real life, but my amazing team was able to capture this special moment on tape. It is just so amazing seeing these animals survive and thrive in the wild while dealing with not only the dangers of the wild but human encroachment as well. Hands down, this was my favorite episode that we got to film.

Catch new episodes of Brave the Wild on Animal Planet, Sundays at 9 p.m. ET/PT.

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