As a teacher myself who used to teach Science to junior school students for years, I have seen a lot of confusion about whales and dolphins and even some frustration concerning their classification.
What is the fuss all about? The frustration is basically coming into play when confused people talk about both dolphins and whales as being fishes so when they are being corrected about it, they tend to hate it. According to them, what lives in the water must be a fish otherwise it wouldn’t be there. Isn’t that right? Wrong!
The fact and the matter is that fishes like the great white shark and marine mammals such as dolphins and whales are not under the same classification simply because of the way nature created their body, the way it functions and differentiated their needs as well.
You see, fishes have gills and take their oxygen directly from the water while marine mammals must go to the surface approximately every 30 minutes to inhale oxygen from directly from the air and get rid of the Carbon Dioxide using their blowhole otherwise they would drown. This process takes only a few seconds but is necessary for their survival. This is why when a calf is born; the mother will push it to the surface to allow it to take its first breath of air.
Another difference is the fact that dolphins and whales have a skeleton made of bones contrary to fishes which have theirs made of cartilage. Also, most fishes give birth to their babies by laying eggs then having the male fertilize them. Later on, the babies are on their own.
The exception to the rule of laying eggs is the shark. You see, sharks likes the great white shark are actually giving birth to several live pups but as soon as they are born, they must fend for themselves. Marine mammals such as whales and dolphins giving birth to usually one calf, nourish them with maternal milk, raise them to maturity and teach them all they know to help them learn how to eventually fend for themselves.
When dolphins and whales are born, the have a thin layer of hair covering their body. Fishes will be covered with either scales or a rubbery type of skin such like the one found on the great white shark.
As you can see, there is no way that dolphins and whales are fishes like the great white shark. There are important differences.
My name is Sylvie Leochko. If you wish to learn more about dolphins, whales or the great white shark, I invite you to visit the following websites: http://dolphins-and-more.com ; http://whales.findoutnow.org and http://great-white-shark.blogspot.com