Top 16 Most Fascinating Facts About Dolphins

Dolphins are omnivorous creatures, and their diet varies with the seasons. Some species migrate seasonally in search of food, with river dolphins often moving to the sea between April and October to hunt. Dolphins feed both at the sea floor and mid-water, and their stomachs can digest both vertebrates and invertebrates.

Common favorites in a dolphin's diet include small fish (like herring and sardines), crustaceans like shrimp, and other invertebrates. Dolphins reproduce by giving birth and nursing their young. Their reproductive organs are internal, with genital slits on their bellies, which is how males and females mate. Dolphins give birth to one calf at a time, with a pregnancy period of around a year.

After giving birth, a mother dolphin nurses her calf through her mammary glands, and will care for it for about 11 months before it is weaned.

Dolphins have streamlined, torpedo-shaped bodies that are perfectly designed for high-speed swimming. Their tail fins provide propulsion, while the pectoral fins and tail help steer their movement. The dorsal fin, present in species that have one, serves to stabilize their bodies during swimming. While each species may differ, most dolphins are characterized by gray coloring, with lighter-colored bellies. Their skin often features contrasting spots and varying shades.

The dolphin's head houses a biosonar system located in the forehead. Many species also have elongated jaws that form a noticeable beak, and some, like the Bottlenose, have a mouth shaped like a fixed smile. Certain species may even have up to 250 teeth. Dolphins breathe through a blowhole located on the top of their heads. Their brains are large and complex, with a structure quite different from most land mammals.

Unlike most mammals, dolphins lack body hair, with only a few fine hairs present at birth that quickly disappear. The exception is the river dolphin, the Boto, which has persistent, tough hairs on its snout.

The dolphin's reproductive organs are positioned toward the lower part of its body. Male dolphins have two slits: one for the penis and the other for the anus. Female dolphins have a single slit that contains both the vagina and anus, with the mammary glands located on either side of the genital slit.

Recent studies at the National Marine Mammal Foundation in the U.S. show that dolphins are the only non-human animals that exhibit signs of type 2 obesity, a condition previously only found in humans. This discovery opens new research avenues for both human and dolphin obesity treatment.

Researchers have discovered that dolphins exhibit highly complex social behaviors. They form tight-knit groups, strategize during hunting, and assign roles to each member for reconnaissance and guarding against predators. These animals use learned skills developed through evolution to hunt more effectively, passing this knowledge onto their offspring. Scientists have also observed that dolphins possess a level of 'meta-cognition' akin to humans—they have the ability to understand language and show empathy. A prime example of dolphin consciousness is the frequent reports of dolphins rescuing humans in distress, as well as their clear mourning behaviors when a group member dies.

Dolphins belong to the Cetacea order, which includes other marine mammals such as whales, sperm whales, and narwhals. Their ancestors were land mammals, and the Cetacea gradually adapted to life in the water over the course of 55 million years. The intelligence of humans, from an anatomical perspective, is often attributed to the large size of our brains. For instance, the human brain weighs around 1400 grams, a horse's brain is about 800 grams, the brain of a chimpanzee weighs around 500 grams, and a monkey's brain is just 75 grams. In comparison, the brain of an Atlantic bottlenose dolphin weighs roughly 1500 grams.

Further studies show that the cerebral cortex of dolphins is even more intricate and folded than that of humans, with a neural density comparable to humans and chimpanzees. This suggests that the structure of their brain is on par with that of primates.

With their high intelligence, dolphins also possess sophisticated communication abilities that bear striking similarities to human language. While dolphins typically use these skills for bonding and social interaction within their groups, they can also use their talents to communicate with other species when necessary.

Dolphins are well-known for their exceptional hearing abilities. However, did you know that they lack a sense of smell? While dolphins have olfactory regions, they do not possess olfactory nerves. You might wonder, 'If dolphins can't smell, do they have taste?' In fact, they do have taste, but they can only sense salty flavors.

Most dolphins also have keen vision both in and out of the water, and they can detect frequencies up to 10 times higher than humans can hear. Although dolphins have small ear openings on either side of their heads, it is believed that they primarily 'hear' through their lower jaws, with sound vibrations traveling through the bone to the middle ear. Dolphins also use echolocation, a biological sonar system found in all species, to detect objects. Their teeth are thought to function as sensory organs, helping them detect sounds and locate prey with precision.

Their sense of touch is also highly developed, with nerve endings densely packed across their skin, especially around their snouts, pectoral fins, and genital regions. However, dolphins do not have scent receptors, so they are believed to be without a sense of smell. They do, however, have taste preferences, showing a liking for certain types of fish. Most of a dolphin's time is spent underwater, and their ability to 'taste' the water helps them detect objects around them.

Even though dolphins are hairless, they do have hair follicles that serve a few tactile functions. It is believed that the small hairs on the snout of the river dolphin, Boto, act as a sensory system, compensating for the species' relatively poor vision.

Each dolphin has its own unique whistle, a high-pitched sound like 'e e e e', used to signal its presence to other dolphins. This discovery was recently published in the American Association for the Advancement of Science (AAAS) journal. Dolphins are known for their remarkable ability to mimic sounds, even replicating strange noises from computers. This ability led scientists to wonder if dolphins could mimic each other's whistles in a way similar to how humans call each other's names.

Currently, a study analyzing hundreds of dolphin whistles has confirmed that they can indeed 'call' each other by name.

The study, conducted by marine biologist Stephanie King at St Andrews University and her team, recorded whistle sounds from over 250 wild dolphins in Sarasota Bay, Florida (USA) between 1984 and 2009, as well as four dolphins from a captive facility. The researchers also carefully observed their behavior while whistling.

The results of the study show that dolphins mimic the whistles of other dolphins primarily to establish communication with specific individuals, not to deceive other members of the group, as some earlier theories suggested. This research provides valuable insight into the complex sounds created by intelligent marine animals.

While female dolphins typically do not remain with a specific group, male dolphin communities can persist unchanged for over 15 years. Researchers have observed that male dolphins of the grey species in Shark Bay, Western Australia, have developed a strategy to increase their access to females by forming three distinct groups, each with specific roles.

The first group, consisting of three members, focuses on attracting fertile females. According to Dr. Richard Connor, this process can take over a month.

The second group, made up of 4 to 14 male dolphins, engages in aggressive actions to either steal females from other groups or defend their own group from attacks. The third group's role is to forge 'friendly' relationships with larger groups. They join forces with these larger groups and work together to protect their females from being taken.

Researchers spent five years studying these behaviors in Shark Bay, a hotspot for grey dolphins, and Dr. Richard Connor, who has studied the species since the early 1980s, concluded that such complex social organization is evidence of the dolphins' remarkable intelligence.

Scientists have long known that dolphins use distinctive calls to identify themselves, but a recent discovery reveals they also use urine. While humans can easily recognize friends by their faces, bottlenose dolphins don't have this ability. Instead, these marine mammals typically recognize each other by their unique calls. However, a recent study shows that dolphins also identify their companions by tasting each other's urine.

The research project, led by scientists from the University of St. Andrews in Scotland and Stephen F. Austin State University in Texas, aimed to further explore the dolphins' 'signature whistles'—the sounds they use to identify themselves.

The study involved captive bottlenose dolphins from two Dolphin Quest facilities in Bermuda and Hawaii. Though these dolphins had years of experience performing for tourists, they lived in seawater tanks alongside other dolphins, making them ideal subjects for the experiment.

Previously, scientists had observed that dolphins quickly passed through each other's urine trails with open mouths. This led them to hypothesize that dolphins could identify something from the urine through taste. To test this, researchers used a small cup attached to a long pole to collect urine from one dolphin and presented it to another dolphin. Meanwhile, they played a signature whistle of a known or unknown companion through a loudspeaker. Remarkably, the test dolphin swam away when the urine didn’t match the call of the known individual.

In another experiment, dolphins were presented with both the urine and whistle from the same individual. The test dolphin eagerly opened its mouth, licked the urine sample, and then swam toward the speaker playing the known whistle. No other vertebrate species has ever been shown to recognize friends by urine in this way.

After conducting an extended experiment, American scientists have confirmed that dolphins have the longest social memory in the animal kingdom. The study revealed that these marine mammals have the longest social memory of any animal species.

To reach this conclusion, researchers from the Institute of Mind and Biology in Chicago conducted a special experiment. The study involved a male dolphin named Bailey, who was separated from his mate, Alice, for more than 20 years.

Despite the long separation, Bailey still recognized Alice's call when it was played through a loudspeaker. This finding led scientists to conclude that dolphins have the longest memory in the animal kingdom, surpassing elephants, whose memory lasts around 10 years.

Currently, American researchers are continuing experiments to see whether dolphins can recognize their relatives when hearing their group calls.

Dolphins, a type of marine mammal closely related to whales, are commonly found in shallow coastal waters. These creatures have the remarkable ability to understand simple human gestures and commands. Their intelligence allows them to organize and categorize everyday objects into groups.

Not only can dolphins process sound and visual cues, but they can also react to images in a way similar to humans. This ability has led scientists to classify dolphins as one of the most intelligent animals on Earth, with humans ranking just third in intelligence.

Millions of years ago, dolphins were not aquatic mammals as we know them today. Instead, they were terrestrial carnivores that lived entirely on land. However, around 50 million years ago, an unknown event forced them to adapt to underwater life, gradually evolving into the aquatic mammals we see now.

Despite being known for their friendly nature, dolphins also exhibit some disturbing behaviors. One such behavior is the act of tossing young dolphins out of the water. While it may seem playful, this practice is a method used by adult males to kill the young, allowing the mother to return to the breeding cycle.

Dolphins don't chew their food, or rather, they can't. Their teeth are designed for gripping their prey. Sometimes, they shake or rub their food along the ocean floor to tear it into smaller pieces, making it easier to swallow.

One hypothesis suggests that since their prey mostly consists of small fish, dolphins need to quickly grasp their meal before it can escape. Skipping the chewing process ensures the prey doesn't get away.

Researchers from the University of Bristol, Zurich, and Western Australia discovered that dolphins living in Shark Bay form friendships based on shared interests—specifically their habit of using sponges as tools for hunting. This tool use is more commonly seen in female dolphins, but studies on some male dolphins showed a new finding: relationships between dolphins seem to form through the use of tools in general.

Dolphins also have individual names and respond when called. Each group of dolphins has a specific whistle, similar to a name, and other dolphins can use these whistles to grab the attention of potential mates. In fact, dolphins are incredibly social creatures.

This discovery opens new questions about the level of communication and 'vocabulary' of dolphins, and could offer clues about the evolution of language skills in humans.

Dolphins would drown if submerged for too long or if water enters their lungs: Despite being aquatic mammals, they can still drown if they inhale water. Like humans, they breathe through lungs, and just 15 milliliters of water in their lungs can be fatal, compared to the 30 milliliters it takes for humans to drown.

Dolphins can't breathe underwater. So how do they sleep without drowning? In fact, they only take short naps of 15 to 20 minutes. However, dolphins don’t sleep fully. Only one hemisphere of their brain rests at a time, allowing them to swim, breathe, and remain alert to predators.

Due to their inability to breathe underwater, dolphins sleep in a hemispheric pattern. This means one half of their brain sleeps while the other stays awake. This sleep model allows dolphins to alternate between each hemisphere, ensuring they get adequate rest. It also allows them to stay active, avoid predators, and breathe.

What's remarkable about dolphins is that they only take half a second to exhale all the air from their lungs. Similarly, it takes them half a second to inhale new oxygen—something that humans can't do. For us, it typically takes 5 to 7 seconds to fully inhale and exhale. If we tried to breathe as quickly as dolphins, we would risk hyperventilation.

Scientists have long known that dolphins use distinctive calls to identify themselves, but they've now discovered that dolphins also use their urine for recognition. While humans can easily recognize friends by their faces, bottlenose dolphins can't do that. Instead, these mammals typically recognize each other by their signature whistles. However, a recent study revealed that dolphins also recognize their friends by tasting each other's urine.

VICE—a research project led by scientists from the University of St. Andrews in Scotland and Stephen F. Austin State University in Texas—was designed to further explore the “signature whistle” of dolphins, the sound they use to identify themselves.

The researchers used captive bottlenose dolphins from two Dolphin Quest locations in Bermuda and Hawaii. These dolphins, despite years of performing for tourists, still lived in sea pens with other dolphins, making them ideal subjects for the study.

Previously, scientists had observed dolphins swimming quickly through urine patches left by others with their mouths open. This led them to hypothesize that dolphins might be able to identify something in each other’s urine by taste. To test this, the researchers used a small cup on the end of a long stick, collecting urine from one dolphin in front of another. At the same time, they played a whistle from a dolphin that the test dolphin either knew or did not know. To their surprise, the dolphin swam away when the urine's taste didn't match the whistle of the familiar dolphin.

In another experiment, urine and the whistle of the same dolphin were tested together. In this case, the test dolphin eagerly opened its mouth and used its tongue to collect the urine sample. Then, the dolphin swam towards the speaker playing its friend's whistle. This behavior is unprecedented in the animal kingdom—no vertebrate species has been shown to recognize friends through urine like this.

Dolphins are marine mammals closely related to whales. Nearly 40 species of dolphins from 17 different genera inhabit the oceans, while a few species are found in rivers around the world, such as the Yangtze, Amazon, Ganges, and Indus rivers. Dolphins vary in size, with the small Maui dolphin measuring just 1.2 meters (4 feet) and weighing 40 kg (90 lbs), while the massive killer whale can reach lengths of 9.5 meters (30 feet) and weigh up to 10 tons (9.8 long tons, 11 short tons).

They are found in oceans worldwide, especially in shallow coastal waters. Dolphins are carnivores, feeding primarily on fish and squid. The oceanic dolphin family, Delphinidae, is the largest family in the dolphin order and the most recent to evolve, emerging about 10 million years ago during the Middle Miocene. Dolphins are known for their intelligence and are widely recognized in human culture for their friendly, playful nature and their interactions with people.

There are nearly 40 species of dolphins across 17 genera found in oceans around the world, with a few species living in certain rivers. Below, Mytour introduces some of the most famous and well-known dolphin species.

Ocean Dolphins (Marine Dolphins): Known as Delphinidae, this family includes over 20 species. Below are some of the most common species:

• Bottlenose Dolphin: The bottlenose dolphin is the most common species globally. Known scientifically as the common bottlenose dolphin, these dolphins are widespread in nearly all the world's oceans. They are also frequently kept in captivity for performances and often appear in movies.
• Killer Whale (Orca): The killer whale, also known as the orca, is the largest species in the Delphinidae family. These dolphins typically live in pods with multiple generations.
• White-Beaked Dolphin: The white-beaked dolphin, belonging to the beaked whale family, was first identified in 1846. Adults typically grow to lengths of 2.3 – 3 meters and weigh between 180 – 354 kg.

Freshwater Dolphins (River Dolphins): While ocean dolphins are well-known, river dolphins remain relatively unfamiliar. Here are some of the famous river dolphin species:

• Amazons River Dolphin – Pink Dolphin: The Amazon river dolphin is the largest freshwater dolphin. Adults can reach up to 2.5 meters in length and weigh as much as 185 kg. They are known for their pink or pink-gray coloration.
• Red-Tailed Green Dolphin – Western Dolphin: These dolphins have a medium-sized body, a sharp snout, and four pairs of whiskers around the mouth. When young, they have brown-gray stripes, but as they mature, their bodies turn completely green with orange-red fins.
• Flower Dolphin – Aquarium Dolphin: Also known as the fire dolphin or elephant-ear dolphin, this species has a robust body, a wide mouth, and beautiful floral patterns on its white-pink body. Native to South America, these dolphins are often kept in aquariums.

Dolphins are large creatures with streamlined bodies that taper to their tails. Their sleek physique allows them to swim at high speeds.

The smallest dolphin species is 1.2 meters long, while the largest can reach up to 9.5 meters. Their weight ranges from 40 kg to 10 tons. Dolphins evolved from land mammals, giving them their streamlined bodies similar to torpedoes, with stiff necks.

Their ancestors’ limbs evolved into flippers for aquatic life. Dolphins do not have external ears, and their heads and skulls are relatively small, with eyes positioned near the corners of their mouths. They have long, sharp snouts and conical teeth that help them catch and crush prey.

As mammals, dolphins breathe air through a blowhole at the top of their heads. When exhaling, they expel water upwards. Their bodies are covered in a thick layer of fat and skin, protecting them from cold water and predators.

Dolphins have a large dorsal fin, two pectoral flippers, and a large tail fin that is deeply cleft in the middle. Their bodies are typically grayish-blue, and they have keen senses, particularly excellent vision and hearing. The positioning of their eyes allows for a wide field of view. Dolphins also communicate using sound, creating complex songs to interact with each other.