Hey there, I’m Yvonne Page Illustrates and you’re watching Facts to Relax, the show where I research topics I find interesting and want to learn more about and then share everything I learn with you in a relaxing and soothing way. Today’s episode is all about dolphins. Where do they live? How do they communicate? Are they as smart as we always people say they are? We’ll answer all these questions and more. But first, let’s get started as always now by taking a deep breathe in and letting it out slowly again while we settle down in a nice comfy spot so we can learn all about what’s dolphinately an interesting topic!
Dolphins are cetaceans, a marine mammal related to whales and porpoises, that have two front flippers, a tail with two horizontal extensions called “flukes,” backbones, and who give birth to live young, some of which even have hair called lanugo covering their bodies when they’re born, just like baby humans. And also like humans, they shed this hair as they grow. It’s hard to believe that a sea creature that looks and lives so differently than us can have so many similarities but I guess that’s just part of the beauty and mystery of nature. Male dolphins are called bulls and females are called cows. There are about 36 different species of dolphins. I say about because every website I looked at gave me a different number, ranging from between 32 and 42 different species. This is possibly because dolphins can get confused with other cetaceans to the point where no one, not even scientists know which is which anymore. For instance, though dolphins are often referred to interchangeably with porpoises, they’re actually different species. The biggest differences are that dolphins have more prominent noses or “beaks,” cone-shaped teeth, and longer, leaner bodies than porpoises. To thicken the plot even further though, at least eight different “whales” are actually dolphins, including killer whales, pilot whales, and melon-headed whales. An orca whale is actually an orca DOLPHIN if we wanted to get really technical, with teeth, size, and the ability to echolocate using biological sonar like other dolphins. Now, let’s stop and consider for a moment whether the 90s classic Free Willy would have been as impactful to an entire generation if we had all known that Jesse was actually helping to free a dolphin, rather than a whale. I mean, dolphins have always been one of my favorite animals so I guess I still probably would have cried when he leapt over that seawall but I rewatched that scene while researching this video and it was definitely interesting to see it through the lens of Willy being a dolphin, rather than a whale.
Dolphins are very versatile in where they live. They can be found in open oceans, on coasts, in estuaries, and even sometimes in fresh water. Four species of river dolphins live only in the Amazon river and can be found nowhere else on earth. The can swim in temperatures ranging from 0 degrees Celsius or 32 degrees Fahrenheit to 30 degrees Celsius or 86 degrees Fahrenheit. Orcas are the only dolphins that live in the Artic and Antarctic because their larger sizes and blubber stores give them more protection from the freezing cold seas there. Most dolphins, however, prefer tropical and temperate regions since they’re warm-blooded mammals and it’s easier to regulate their body temperatures in warmer water. This explains why it’s much more common to have dolphin sightings in warmer areas and why they’re less likely to be housed at aquariums in colder climates. Speaking of aquariums, the more we learn about these amazing sea animals and their relatives, the less and less we see them in captivity. Being in aquariums can cause both physical and mental problems for dolphins and for that reason, capturing them for our own amusement is starting to become more and more taboo. In Europe and Canada, very few dolphins can be found in aquariums and in the United States, the numbers of cetaceans on display have also dropped, though not as much.
While dolphins, and other cetaceans, live their whole lives in the water, they’re different from fish in many ways. Dolphins must breathe air to survive so they need to regularly swim up to the surface, unlike fish who extract their oxygen from the water. Also, unlike fish, they’re warm-blooded and need body fat, or blubber, to keep them warm. Instead of laying eggs like fish, they give birth like other mammals, usually to a single baby every one to six years, and they feed them from their nipples, which are inverted and located near their bellies. Finally, dolphins evolved from land mammals whose legs were on the underside of their bodies…think dogs or cats as an example of that. Because of this, their tails move up and down while they swim, rather than side to side like a fish’s tail.
Though dolphins are relatively slow swimmers, normally moving only about 2 miles per hour, they can sprint through the water at speeds of up to 30 miles per hour when they feel like it. The fastest dolphin, the Orca, has been caught reaching burst speeds of 34.5 miles per hour.
Dolphins eat fish, squid, and crustaceans but the way they capture and consume their prey may vary depending on their location and species. When dolphins hunt, they may use several different techniques. Sometimes they may whack fish with their tails, stunning them and making them easier to catch. Other times they’ll blow bubbles that herd prey to the surface of the water. One strategy, practiced by bottlenose dolphins in the Bahamas called crater feeding, is when they use their echolocation abilities to figure out where fish are hiding in the sand and then dig little craters with their noses into the sand to find the food. Another strategy developed by dolphins in Florida involves several dolphins working together to trick fish. One dolphin disturbs mud in shallow waters around a bunch of fish to create what is essentially a mud wall in a circle around them. In an attempt to escape, the fish will literally jump over the wall, where other dolphins are waiting to catch them in their mouths. Dusky dolphins in the Gulf of Nuevo in Argentina also work together to catch fish. These dolphins will leap out of the water, not just to scare their prey but also to signal to other dolphins in the area that they should come join the feast. It’s like the dolphin equivalent of calling out “dinner’s ready!” to their family. Orcas in the Punta Norte part of Patagonia have developed a completely unique strategy of capturing sea lion pups where, during high tide, they will race to shore and grab the pups, risking stranding themselves on the beach. It’s believed that none of these behaviors are hard-wired into the dolphins’ DNA. It’s all learned behavior, passed on from mothers to babies from generation to generation. In general, dolphins will eat their fish whole, rather than chewing, and purposely head-first so that the spines of the fish don’t get caught in their throats. The only exceptions that we know of to this rule are that they may bite the heads off catfish to avoid those spines, and dolphins who eat octopuses will thrash them around a bit first so they don’t choke on their clinging tentacles. Depending on the species, a dolphin may have anywhere from 14 to 240 teeth to help chomp down their dinner.
Rather than breathing through their mouths, dolphins breathe through their blowholes, a flap of skin on the top of their bodies near their heads that they can open and close to allow air in and out. Think of it like nostrils except there’s a flap over the hole keeping it closed while they’re underwater so nothing can get in. When they surface, they “chuff” which clears any water over the flap and exhales their breath out at the same time, then they breathe in when they sense the pressure change after the water’s clear. This whole process only takes a fraction of a second. Because of their need to breathe regularly, typically breathing 1.5 to 4 times per minute, most dolphins live in the upper 10-150 feet of water. When they dive to deeper lengths, they’re able to hold their breathe for several minutes-sometimes as long as 15 minutes, though that’s not a regular practice. Naturally, baby dolphins or calves can’t hold their breathe for as long as adults and because of this, when they nurse, they have to frequently stop for air. This has caused dolphin’s milk to evolve to be more nutrient dense and fattier than that of other mammals.
Speaking of baby dolphins, a dolphin pregnancy will last between nine and sixteen months and when they’re born they normally come out tail first, which keeps them from drowning before they can take their first breath. When the babies, called calves, are born they weigh between 22 and 44 pounds and measure about 39-53 inches long. They drink milk from their mothers for several years and eventually wean as they learn to catch their own fish. Calves are able to swim and breathe on their own within minutes of their birth but that doesn’t mean they leave their mother’s side. In fact, they generally stay close to mom for 3-6 years and stay with the mother’s pod for life. For the first several weeks of life, a newborn calf must stick close to its mother, otherwise it’ll sink. Essentially, the calf is sucked alongside the mother as she swims by the current, even while it sleeps!
Mother dolphins are solely responsible for raising babies, with fathers taking no part in the childrearing, outside of mating. In fact, males may even be a threat to a baby since a new mother won’t mate for several years after giving birth.
Dolphins love to talk and are very social. They live and hunt in pods that normally range from 2-30 dolphins, depending on the situation and species but sometimes pods will join together and form super-pods that may contain hundreds or even thousands of individuals. When a super-pod is formed it’s probably for the purposes of mating or hunting in a very abundant area and once the activity in question is complete, they’ll revert back to their smaller pods. When bottlenose dolphins sleep, they shut down half their brain and close one eye, while leaving the other eye open and alert, literally to “keep an eye out” for predators and to make sure no one in their group floats away while they sleep. Dolphins, even ones from neighboring pods, may babysit for each others’ children. They’ve been known to fight, form alliances, and even show signs of love towards each other and their human caregivers in captivity situations. Researchers also will note that dolphins, like humans, are very unique individuals, showing character traits like shyness and outgoingness.
Dolphins like to play with seaweed and whatever else they may find in their environment. They’ve even been seen tossing jellyfish back and forth like frisbees. Likewise, dolphins have been known to make tools from things around them, which is a great sign of intelligence. For instance, in Shark Bay, Western Australia, dolphins have been seen fitting marine sponges – sea animals that look like plants – over their noses to protect them from sharp rocks as they dig around looking for fish to eat.
To communicate, dolphins whistle, click, squeak, moan, bark, groan, yelp, and more and though the sounds mean nothing to us, each noise helps communicate something to their friends and family. They often make clicking sounds and then measure the echoes that return, which helps them know what’s around them in terms of size, shape, and speed. This process, called echolocation, helps them hunt. Noise from ships, oil and gas drilling, seismic surveys, and underwater construction can disturb sea life, including dolphins. This is called “noise pollution” and can prevent dolphins from communicating, reproducing, navigating, and finding prey. It can sometimes even lead to death. Unfortunately, noise pollution isn’t the only human-made danger to wild dolphins.
Dolphins tend to live between 20 to 80 years naturally, with the larger species normally living much longer than smaller dolphins but unfortunately, their lives can quickly be cut short because of human behavior. In some cases, it’s intentional like when river dolphins are killed to be used as bait for catfish by fisherman in the Amazon but other times, it’s accidental. Dolphins can easily get caught up in fishing gear out at sea so wildlife organizations have begun working with fisheries to create gear that includes alarms or pingers that would acoustically alert cetaceans of the presence of nets so they can avoid them. When you buy cans of tuna from the grocery store that are marked as “dolphin safe,” it’s meant to indicate that no dolphins or other marine animals were harmed when the tuna were caught, although, it’s not always guaranteed that that’s the case. Recently, several big name tuna brands have come under fire for using the “dolphin safe” label on their tuna when really, some of the fisheries they source from may not be safe for marine life at all. Unfortunately, it seems that if you want to be sure that your tuna is actually dolphin safe, you must pay the price-namely a higher price per can. If you can afford to do so, spending more for tuna that’s been “pole-caught” or “troll-caught,” meaning that it’s been caught using a slow moving boat dragging lure lines, it’ll help you be sure that dolphins really haven’t been hurt or killed during the process.
Because of fishing, noise pollution, and climate change, a few species of dolphins are in danger of extinction, including Maui’s dolphin, which lives only in the coastal waters of North Island, New Zealand. Maui’s dolphin is the most endangered species, with less than 50 individuals remaining along the 22-mile stretch of coastline. New Zealand’s other sub-species, the Hector’s dolphin is also in decline, both mainly due to entanglement in fishing nets.
Dolphins are very important to their ecosystems. As well as eating smaller fish, they are sources of food for other marine creatures like sharks and their presence helps balance the marine food chain. This is only one of the many reasons why we humans must take care to keep them safe. Not only are dolphins important animals for the oceans and rivers they live in, they’re also very smart, beautiful, and worthy of our respect.
How smart are dolphins really though? Arguably, they’re the most intelligent animals in the ocean, actually. We all know dolphins can be trained to do simple tricks in exchange for treats like jumping through hoops, giving kisses, and more, as is evidenced by countless aquarium shows. But really, dogs, and lots of other animals can be trained to do similar tricks so how do we know whether dolphins are smarter than them?
Well, researchers have done extensive experiments to find out. One researcher and cognitive biologist, Dr. Stan Kuczaj from the University of Southern Mississippi has worked with dolphins in various aquariums and other captivity situations to test the different ways dolphins problem solve. He has set up experiments that involve doing tasks the dolphins aren’t used to like solving mazes or working in pairs to open objects and every time he creates a new test, the dolphins ace it in no time. He also has been working with dolphins on the Island of Roatan in the Honduras to test their ability to read! In these experiments, he shows dolphins large white cards with black symbols on them along with performing a hand signal that the dolphins already know, for instance having a card with an arrow pointing down along with performing a hand signal to tell the dolphin to go down under the water. Weeks later, he’ll come back and show the dolphin just the card with the symbol on it to see if it reads, remembers, and reacts to seeing the symbol. Unsurprisingly, dolphins aced this test too, proving that they’re capable of actually learning to read, though maybe not a novel. Kuczaj has made it clear that his experiments are always done on a voluntary basis. If a dolphin isn’t interested in participating, he never forces it. That has, of course, meant that he has to make it a point to create tests that the dolphins find engaging enough to want to participate in.
Other, less invasive experiments have been done where researchers have placed mirrors in dolphin’s environments to see what their reactions may be. This experiment has been performed independently in different aquariums and facilities but with similar results. When looking in the mirrors at Dolphins Plus in Key Largo, Florida, researchers witnessed adult dolphins making different squeaks at the reflections, while younger dolphins would approach in groups. Researchers at the National Aquarium in Baltimore similarly did a study of young bottlenose dolphins and how they would react with their own mirror images over the course of three years. Their results showed that even dolphins as young as 5 months old may show signs of recognition, like blowing bubbles, twirling and barrel rolling in front of the mirror, watching their own movements, and even examining themselves and checking themselves out from angles they can’t see without a mirror. Even the dolphin in the study that was introduced to the mirror later in its life, at 14 months, immediately appeared to recognize itself. To compare, it usually takes human babies until they’re about 15-18 monthsto recognize themselves. Does that mean that dolphins are smarter than humans? No, not necessarily. But self-recognition is a sophisticated cognitive process only seen in a few animals, including great apes, elephants, and magpies. Animals who can recognize themselves tend to have large, complex brains, social awareness, and the ability to empathize.
Because it’s important to study wild dolphins in their natural habitats as well as captive dolphins, one researcher, Denise Herzing started the Wild Dolphin Project in 1985, in order to track the lives of a group of wild spotted dolphins in the Bahamas long-term, studying their body language, complexity of their societies, and most particularly, their communication systems. To date, they’ve identified about 40 different types of vocalizations and Herzing claims that everything they’ve found shows that dolphins can problem solve, think in abstract terms, and understand language. Through their research, they’ve found that each animal has a “signature whistle” which is individual to a dolphin, acting sort of like an identifier or a name, letting other dolphins know exactly who’s who, and may be used when dolphins are meeting for the first time or reuniting, but of course, they can make lots of different sounds. In fact, Herzig has created a machine called the C.H.A.T which stands for “Cetacean Hearing and Telemetry” that allows her to communicate with dolphins underwater by both sending and recognizing dolphin sounds that she’s programmed into the device from her years of research. If a sound comes through the machine that’s been programmed it will read out to her an English translation for a word she’s recognized the sound to mean. Likewise, she can send out words in the form of dolphin-recognized sounds and watch for their responses. This machine is especially helpful since some dolphin sounds are outside our range of human hearing so the machine is much better at recognizing dolphin language than the human ear. Since dolphins are able to copy many of the noises humans make, when we’re around, dolphins may mimic our noises and movements, showing that they can be just as interested in us as we are in them and opening up a world of communication never seen before!
Well I don’t know about you but I can’t wait to see what comes next in the world of dolphin research, especially in regards to communication. But until I can have a true one-on-one conversation with a bottlenose, I guess I’ll just have to keep watching videos and learning more about these amazing creatures. As we finish up this episode of Facts to Relax, I invite you to subscribe to this channel, and if this video was something you enjoyed, hitting the like button to let me know. As always, thank you so much for joining me and letting me share my research with you and I hope to see you back here soon so we can color and chill together again! Bye!
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