Human beings come in many colours. Domestic dogs come in many colours too. It seems very few other lifeforms on earth are like humans and dogs. Have you ever wondered why? “I saw this large animal on television yesterday. Do you know what it is?” “What colour was it” I ask. “It had black and white stripes.” “Oh, that’s a zebra. It looked like a horse, didn’t it?” “Yesss!”
This conversation makes one basic assumption: the zebra is always striped black-and-white. Some people will tell you that of course this is true. That’s what a zebra is. If it was pure white, it wouldn’t be a zebra, would it? You would be correct, but also wrong. Understanding why you are both correct and wrong is the story of genetics. A terribly boring subject to most people, but a hugely fascinating world to others.
No one is surprised that your son looks like you, or your sister has the exact same hair as your grandmother. You would say “Of course they would. They are our family. We share the same blood.” In fact, it has nothing to do with your blood, and everything to do with the genes you share with your parents and your offspring.
All around the coast of Borneo lives an animal that shows a striking variation in colour. Of the several species of dolphins found in the seas around Borneo, one species has mystified scientists for many years. This is the Indo-pacific hump-backed dolphin. Its Latin name is Sousa chinensis. This is a large dolphin, growing to 2.5m in length, with mature adults reaching weights of 200kg. They live in small family groups of five or six animals. Adults are usually solitary, or in pairs, and only form larger groups when young are present.
So what’s so special about this dolphin? Well, it is pink. “So what?” you might ask. It wouldn’t be that much of a deal is all of them were pink, but the curious thing is that they are not all pink! A family group may consist of pink dolphins, grey dolphins and sometimes even spotted dolphins. And they are all one family: father, mother and children.
Are these albinos? Albino animals are common in nature, an aberration of genetics when some individuals in a population, like some individuals in human families, are born with a different genetic make-up, causing their skin to be without the pigment called melanin that gives your skin colour. The more pigment you have, the darker your skin is. Without melanin, you become pink. And your eyes are red.
All this sounds rather technical, doesn’t it? Shall we forget about why these dolphins around Borneo are pink, and let’s ask a different question. What does it mean to an animal that lives in a family where not all members of the family are the same colour? As we discussed earlier, all (well, almost all) animals in nature are easily recognisable as belonging to the same type by their patterns, colours and shapes. A zebra is always striped, and if one wasn’t, it wouldn’t be a zebra!
The fact that this dolphin can recognise its mother, son or cousin when they are completely different makes them rather like humans. Your brother has curly hair, and you have straight hair, but you know he is your brother. You are both human beings, and you both have the same mother and father, but you look so different! Why does this happen in humans but not in most other animals? And why is this dolphin just like us? Has it anything to do with our brain capacities?
We all have heard that humans only use 10% of their brains. This is utter nonsense! We use 100% of our brain, but just not all at the same time. Dolphins do the same, but…. A dolphin’s brain is much larger than a human’s. Human brains have three lobes, dolphins have four. A human baby’s brain is 25% of an adult human’s at birth, and reaches about 80% in three to four years. A dolphin baby’s brain at birth is 42% of its mothers, and reaches 80% in 18 months.
What scientists do know is that brain size and brain growth are two factors in developing intelligence. This we know for sure. We can then conclude that both humans and dolphins are exceptionally intelligent creatures. Who knows, the dolphin may even be more intelligent that humans? Can this therefore perhaps be an explanation? Highly intelligent creatures do not have to look exactly the same? I am grey, but my baby can be pink, says mummy dolphin. I am short and fair, but you can be tall and dark, says daddy to his handsome son!
Science hasn’t discovered the answer to this question yet. We expect someday they will find out. And then they can move on to the next question…. the dog must be exceptionally intelligent too, wouldn’t you say?