Hello my little readers!
Last week we talked about the scary sharks and we understood them a bit better. Today we are going to learn from another animal, let’s see if you can guess which animal it is. It lives in the seas, but it is not a fish. It is known for its intelligence, playfulness and elegance. This friendly animal is very agile and loves to jump in and out of the water. Also, it is famous for its amplified senses of sight and hearing. Can you guess which animal it is?
Yes! You are right! it is the beautiful dolphin.
Dolphins belong to the Cetacean family just like whales and porpoises. Cetaceans are aquatic mammals, which means they are mammals like humans but live in the sea like fish.
As humans, aquatic mammals, give birth to little ones and nurse them with milk, they breathe through their lungs and they are warm blooded.
Cetaceans are divided into two groups the baleen whales and the toothed whales. Whales with no teeth belong to the division of baleen whales, while dolphins, porpoises and other whales with teeth belong to the toothed whales’ group. However, not all the whales with teeth are whales. Some fall under the family of the oceanic dolphins, the most surprising is the killer whale or Orca that turns out not only to be a dolphin but be the largest among them.
Dolphins could be distinguished between the oceanic dolphin and the river dolphin. There are between 36 different species of oceanic dolphins, while there are only 7 species of river dolphins. Oceanic or marine dolphins live in all the oceans and coastlines waters. Being warm blooded mammals, most marine dolphins prefer the tropical and warm water as it is easier for them to regulate their own temperature in warmer waters. However, the orca prefers the freezing waters of the Artic and Antarctic’s Southern oceans, their large size protects them from the low temperatures of these waters. The river dolphin as its name suggest prefers the fresh water of the rivers and lakes, they are found in fresh waters of South America, China and Southcentral Asia.
Is there any difference between a river dolphin and oceanic dolphin, you might wonder? And the answer is yes.
River dolphins have smaller eyes and poor vision that is due to the fact that they live in muddy and dark waters, while oceanic dolphins have good eyesight. Oceanic dolphins have a short snout, while river dolphins have a thin and long shout, four time bigger than most of the snouts of the marine dolphin. River dolphin are slow swimmers and rarely jump while oceanic dolphins are fast swimmers and love to jump.
Fish have gills and breathe under water, but dolphins are mammals and need to come out to the surface to get air, they need nostrils to breathe air into their lungs, just like humans do. Do you know how the nostrils of the dolphin are called and where they are located? The nostrils of a dolphin is that little hole that you see on the top of their heads and it is called the blowhole.
Dolphins exhale first and inhale after and they do this in a fraction of a second. They need to exhale first in order to clean the hole of the water that has entered into the hole then they can inhale fresh air that will go into their lungs.
Dolphins have one baby at a time, the young dolphin is called a Calve. Dolphin pregnancies varies from 0 to 18 months depending of the species, while human pregnancies commonly last 9 months. Humans and most mammals are born with their headfirst, however dolphins are born with their tail first in order to minimise the risk of drowning as the birth can take a couple of hours.
Did you know that dolphins have a belly button also, although it is not like your belly button, dolphins have a smooth belly button that reflects the spot where their umbilical cord was connected to their mum’s womb. As humans, Calves are totally dependent on their mums to eat, they drink their mums’ milk until they are 2 or 3 years of age. During that period their mum teaches them to catch and eat little fish also, so the more they learn to catch fish the less milk they will take from their mum until they become totally independent.
A common thing between humans and dolphins is the importance and closeness to family as well as their social aspect. Dolphins live and travel around the world with their family and maybe with some family friends. This group that travels together always is called a “pod”. Every pod is different depending on the species, it can go from only 2 members to 30 members. Sometimes pods come together with other pods forming what is called a super pod reaching hundreds or thousands of dolphins.
I would really love to see so many dolphins gathering and jumping together, wouldn’t you? These super pods last for short periods of time, different from a regular pod which last for a lifetime. Super pod gatherings happen for a specific activity, for example when there is lots of prey in a particular area or when it is mating time, but once the activity is over dolphins go back to travel and be with their regular pods. Dolphins can form super pods many times in their lifetime.
Dolphin communicate among themselves by making vocally sounds, touching and using body language. When they communicate by sounds, dolphin use high pitched clicking and whistles. Each dolphin has a unique whistle, vocal pitch, which is used to identify itself. They whistle to communicate with the members of their pods and other pod members. For example, when a calf and a mother are separated, they whistle until they are reunited. Sometimes all the members of a pod will whistle constantly so everyone knows who is around. Other times, clicks are used to see by sensing what is around them through echolocation.
Even though, the oceanic dolphin has extremely good sight inside and outside the water, sometimes the water it not clear and their vision is limited, or it is very dark in deep waters so communicating with echolocation is much better. When a dolphin clicks it produces a wave of sound that travels 5 times faster in water than in air, this wave of sound travels until it hits a something and when it does, it bounces back to the dolphin, in this way the dolphin, not only knows how far is the object, because of the time it took for the sound wave to come back to it, but also the direction the object its travelling to, the position in respect to the dolphin and the size and density of the object. Would you be able to emit a sound where it echoes and close your eyes and be able to identify how far or how big the object is based on the sound that bounced back to you? Quite impressive correct?
Dolphins communicate with body language to alert other dolphins when they have found a spot with lots of prey to eat, alert them when there is danger or just to romance a mate.
Most of Dolphin like to eat fish, crustaceans, squid and octopuses, however, what they eat depends on the species of the dolphin. Killer whales or Orcas, being so big, need more substantial food so they eat sea lions, seals, turtles, penguins, whales and sharks. Dolphins do not chew their food, if they cannot eat it whole they break it and then swallow it in pieces.
Many times, dolphins hunt together, in a way that everyone cooperates. While some dolphins surround the prey of fish to round them up in the middle, others eat. They will continue taking turns until everyone has eaten, this way of hunting is called herding fish.
Dolphins and whales are considered to be the most intelligent animals in the sea. Dolphin are good at learning and what is surprising is that they are good at passing what they learned to others. For example, the eldest family member teaches the youngsters fundamental survival skills.
Dolphins are known for their mimics and to be quite fast learners, they are able to solve problems, they demonstrate self-awareness, joy and playfulness when they are happy and grief when they are sad. But, how can a dolphin be sad if they are always smiling? You are probably thinking, which is quite a fair thought! Dolphins have a constant smile on their faces due to the configuration of their jaws and their mouths which are permanently curved.
So, when are dolphins sad? As stated many times by dolphin project organisations, dolphins are sad and suffer when they are kept in captivity. In captivity dolphin are kept away from their families or Pods whereas otherwise they would have stayed together all their life’s. Also, a free dolphin swims freely around 100 kilometres per day in the open ocean, this is impossible under captivity where the space is limited causing great frustration to the dolphin.
Do you think captivity of dolphins should be stop and all dolphins sent back to the wild? I will leave this question to you so you can think it over, do some research and draw your own conclusions, you can always of course share them with me in the blog.
Well, my little friends, I hope you all enjoyed learning about dolphins today! As usual, I have a little quiz below for you to refresh all that you have just learned! Even more fun, you could make this into a quiz and ask your family members to see who gets them right!
Take care my sweet little friends and until the next time!
Do dolphins breathe under the sea? True / False
Answer: False. They need to come out to the surface to breath air.
Is a Killer Whale a whale? True / False
Answer: False. Killer whales or Orcas fall under the subdivision of the toothed whales of the cetacean group and within that subdivision they belong to the Dolphins. Moreover, the killer whale is the largest Dolphin.
A baby of a dolphin is called “calf”. True / False
Which is the most common specie of aquatic dolphins?
Answer: The bottlenose dolphin.
Do dolphins nurse their babies? True? False
This is correct as Dolphins are mammals, so they give their milk to their babies after they are born.
Are dolphins and whales considered the most intelligent animal in the sea? True or r false
Why do dolphins exhale first then inhale? Because they need to clean the water that has entered into their blowholes before they can inhale fresh air into their lungs.
What is echolocation?
Answer: Echolocation is a special sensor which permits dolphins to identify subjects by interpreting the echo of the sound wave produced by their click, after it has hit the subject and bounces back to them.
Do all dolphins whistle the same?
Answer: No. Each dolphin has a unique whistle, and this is what they use to identify themselves.