Dolphins, are NOT FISH, a common misconception. They are highly intelligent and charismatic marine mammals.
Bottlenose dolphins, the ones you see in the images here, belong to the genus Tursiops and are the most common members of the family Delphinidae, the family of Oceanic dolphins. They are widespread, inhabiting the warm and temperate waters worldwide.
There are 3 distinct species of Bottlenose dolphins found across the world. The Common bottlenose dolphin (Tursiops truncatus), the Indo-Pacific bottlenose dolphin (Tursiops aduncus) and the Burrunan dolphin (Tursiops australis). As you might have guessed, the species found along the coastal waters of India is the Tursiops aduncus, the species I had a great encounter with, out in the Andaman sea.
The Bottlenose dolphins can grow to a length of around 4 meters and can weigh about a 300 kg. They are known to live for more than 40 years. Their elongated upper and lower jaws form what is known as the rostrum, their snout. The curved structure of the snout give them their characteristic smiling face.
Dolphins are highly intelligent animals, displaying abilities of mimicry, self recognition and use of tools while looking for food among many others. They are also known to pass on cultural knowledge from generation to generation. Dolphins have the 3rd largest encephalization ( meaning, the ratio of the brain mass to the size of the animal ) of all mammals on Earth, sharing close ratios with those of humans and the great apes.
A Quick fact — Some researchers hypothesise that the number of nerve cells (neurons) in the cortex of the brain predicts intelligence in mammals. A 2019 study estimated the number of neurons in the cerebral cortex of three common bottlenose dolphins and found numbers ranging from 11.7 to 15.2 billion neurons. The human average being approximately 16 billion.
Though the Dolphins are aquatic and spend most of their time under the water, they cannot breathe out there. They have to surface every few minutes to take in a gasp of fresh air. The blowhole on the top of their heads ( as you see in the image above ) is the functional nose which they open as they surface to breathe. It is closed by a membrane while under water.
An interesting fact is that, Dolphins can exchange up to 80% of the contents of their lungs when they inhale. Humans, by comparison, can only exchange 17% of the air in their lungs when they breathe.
- Animal Fact Guide
Also, dolphins are not involuntary breathers like humans. They have to consciously surface every few minutes. This means that Dolphins cannot fully sleep. One side of their brain must always remain active so that they remember to breathe.
Dolphins are very social and fun loving creatures too. They swim around in large groups called pods, communicating between each other using a variety of pulses, whistles and body language. Dolphins are know to form friendships that last decades.
The whistle of a Dolphin is its unique signature, something that an individual is born with. They can identify each other by their whistle. The groups stick together, hunting, helping taking care of each other’s young, protecting each other and simply having fun.
Dolphins are know to be attracted by the wake of ships and boats. They seem to follow the large boats to enjoy a lovely surf over the waves created. It is also a good opportunity to look for a meal I guess, as the fish on the surface get dispersed by the ship’s movement.
This was exactly what I encountered while on a ship out in the Andaman sea. It was a bright afternoon. We just had finished a lovely lunch on the ship and lazying around when we noticed something out in the sea which seemed to be fast approaching our ship. Leaping and bouncing off the water’s surface, we could clearly see that they were the Bottlenose dolphins.
The pod was a big one with young ones too. Here is a mom and her calf.
The fun element was well and truly there. Individuals were throwing themselves out of the water and putting up a full on display.
Image above: © Sagar Vibhute
They came right up close to our ship and were swimming around, at times, very close to water’s surface. Looked like they were teasing us.
One individual came right next to our ship and breached the water’s surface. The huge, majestic mammal was entirely visible in all its glory. What a sight that was !!
Before diving back in, with a huge splash….
After a few minutes of the mind-boggling display, the dolphins were all gone. Bearing witness to this natural wonder, powerful thoughts started rushing to my mind. Such beautiful mammals, who should be roaming the wild waters are instead put in theme parks and trained to perform tricks, just for our entertainment. Such a shame!
After a period of lull, the beautiful flying fish started coming out to satiate our hearts. These were no less with their amazing displays.
Flying out of the water….
They skimmed across the surface using their powerful tail fins, covering quite a distance by doing so.
It was nothing short of spectacular!
All in all, it was a truly memorable and fun filled afternoon. And the rather monotonous ship journey turned out to be a scintillating experience.