People have always admired dolphins because of their gracefulness in the water and intellect. That’s why they’ve been a massive attraction at marine aquariums worldwide.
However, there’s a lot more to this aquatic mammal than most people understand. Here are some amazing facts about dolphins that will blow your mind.
Orcas are dolphins
They might look like whales because they are huge and considerably bigger than most, but the mighty killer whales are actually dolphins. Orcas were initially called “asesina ballenas” or “whale killers” after ancient sailors saw them hunting and preying on other whales.
Eventually, as time passed, their names flipped, and they were known as killer whales. You will see plenty of similarities if you ignore the black-and-white coloration and compare their body shape with other dolphins.
Courtesy of Holger Wulschlaeger
Dolphins are carnivorous
Dolphins feed on other small animals. They have an extensive range of prey, including fish, octopus, squid, and crabs, among other sea creatures. For orcas, that extends to seals, penguins, seabirds, and even sharks.
They hunt other aquatic animals by either outswimming them (because they can be really fast and agile) or by coordinating in group hunts. Orcas are even known to swim to shore just to ambush seals by the beach.
Dolphins sleep with only half of their brain
When dolphins (and whales) sleep, they only “shut down” half of their brain and the eye opposite to that side. The other hemisphere remains active in order for the animal to be able to continue regulating functions like breathing, muscle control, and maintaining body heat.
They can also detect and react to danger quickly enough in this state. In a span of 24 hours, each side of their brain averages about 4 hours of downtime.
Courtesy of HAMID ELBAZ
Dolphins have two stomachs
To maintain their body temperatures at an optimal rate, dolphins need a steady supply of energy. However, fish are not always an available resource because they are constantly on the move, and chasing them also takes up energy.
To solve this problem, dolphins rely on two stomachs: one for digesting and one for storing. So, they eat as much as possible when fish is available and abundant, never worrying about overeating. This way, they can continuously produce energy for metabolism even when not hunting.
Dolphins are highly intelligent
Of all the animals, dolphins are regarded as the smartest, probably rivaling even humans. Scientists have observed dolphins display amazing problem-solving skills, use tools, play with other dolphins and animals, recognize their reflections in mirrors, empathize with other dolphins, display complex social behaviors, and more.
They also show distress, loneliness, happiness, and excitement. By examining dolphin brains, scientists have also discovered that they have larger brains and a well-formed neocortex (the part responsible for self-awareness and problem-solving skills).
Dolphins use echolocation
Just like their aerial cousins, the bats, dolphins can use a navigating technique called echolocation.
They use short, burst pulses called “clicks” that travel long distances in the water and bounce off walls and objects to warn the dolphins of upcoming obstacles in their path. This enables them to navigate through murky waters.
Learn more about echolocation through this short video: Dolphins by Interesting Engineering
Dolphins will die when they stay out of the water for too long
Even though they are perfectly fine breathing out of the water because of their lungs, dolphins increase the risk of dehydration and overheating when they are not in the water. They are well-equipped with mechanisms to increase body temperature but rely on water to keep cool.
Dolphins live for a long time
On average, the life expectancy of dolphins is around 25 years. However, some individuals live until 50 years old or older. The longest-living dolphins on record (Nana and Nellie) lived 42 and 61 years, respectively.
Courtesy of Guillaume Meurice
Dolphins can hold their breath longer than humans
Despite relying on lungs for breathing, dolphins can hold their breath for long periods because of several adaptations:
- The blowhole they breathe through gets covered by a muscular flap to prevent water from entering the lungs.
- Dolphin lungs have more air sacs than human lungs.
- Dolphins can use selective circulation when they dive, conserving oxygen flow only to necessary organs like the heart, brain, and tail (so they can continue swimming).
Dolphin skin is vulnerable to environmental pressure
Dolphins have very smooth and slippery skin. This is because their skin cells are pretty active. They sloop off their skin almost continuously and then completely regenerate in under two hours. Unfortunately, this state of activeness also makes their skin more vulnerable to pollution and irritants in the water.
Highly active cells (like dolphin skin cells) are more susceptible to carcinogenic chemicals and are more likely to become cancerous. This makes dolphins vulnerable to environmental pressure.
Frequently Asked Questions about Dolphines
Do dolphins have good eyesight?
Dolphins have special mirror cells that help reflect the light a second time so they can see better in dark or low-light conditions.
However, studies also show that they lack cone receptors (the visual receptors that pick up color), which suggests that they might be colorblind. This is not surprising because light usually penetrates the water only until 200 meters down. In not-so-ideal conditions (murky), that number will be even less. So, colors won’t matter too much.
Do dolphins have teeth?
Yes, dolphins have teeth—and only 1 set to last their lifetime. However, they don’t use their teeth for chewing since they swallow their prey. The teeth are primarily for grabbing or defensive purposes.
The number of teeth depends on the species of dolphins. The long-beaked common dolphins have the most space in their mouth and therefore have the most teeth of all dolphin species, which can be up to 240 teeth. The species with the least teeth, the Risso’s dolphins, can only have as little as 4 to 14 teeth.
Want to know more about dolphin anatomy? National Geographic offers a special book about dolphins for children, so you and your child can learn together!
Are sharks afraid of dolphins?
Sharks will attack dolphins if given a chance (like in an ambush or when a dolphin is alone or showing signs of weakness). However, they avoid encounters with dolphins as much as possible, mainly because:
- Dolphins are intelligent and fast, so outswimming them is next to impossible.
- Dolphins are more agile in the water because of their build and horizontal flukes (tails). They also have better maneuverability than any shark.
- Dolphins swim in groups, so catching one off guard is rare. Also, sharks risk getting attacked by the whole pod if they initiate contact.
- Dolphins have a very thick and strong snout that they use as a battering ram. When sharks get hit by these fast-swimming battering rams, they often have serious internal injuries.