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How the elephant got its trunk

The controversy around this important evolutionary topic is still of a gargantuan nature. The discussion equals the classic topic of the neck of the giraffe? How did the elephant require its long and flexible trunk?

There is Kipling's famous story of an 'Elephant's Child' acquiring a trunk by being pulled on the nose by a crocodile. We cannot give this theory any support because it is a clear case of Lamarckism. How otherwise would the trunk be passed on to the next generation?

More serious scientists point out that there are only 3 ways for a large animal to drink water. It can grow a longer neck, it can get down on its knees, or it can develop a proboscis or trunk.

In case of the giraffe the neck clearly got elongated. Neither the elephant nor the giraffe like to bend down very much to drink. Therefore both the elephant and giraffe can be classified as either very lazy or not very religious animals.

Scientists point out that the head of the elephant is too heavy to put on a long neck, which explains why giraffes seem to have relatively small heads. The only option for the elephant was therefore to develop its trunk as an extension of its head.

Elephants didn't always use to have a trunk and the reason for this seems to be that elephants didn't always use to be huge. The earliest elephants were rather smallish creatures. The first elephant-like creature was Moeritherium from the Eocene of North Africa. It weighed only a bit about 250 kg, which is rather less than the 3-6 ton of a modern African elephant.

We find this explanation rather a blatant example of circular reasoning: The elephant didn't have a trunk because it was small. The elephant became larger and needed a trunk. A small elephant doesn't need a trunk. The modern elephant has a trunk because it is huge.

Why didn't Moeritherium simply evolve a smaller head and a long neck similar to the giraffe?

As often is the case the answer can be found in the circus. Indeed the circus has solved more scientific conundrums than any other social institute in our society. A remnant of ancient behaviour can still be witnessed in the circus where elephants parade around in a single queue holding each others tail with their trunks.

We propose that the elephant got its trunk because the very first elephants evolved in a thick rainforest and were social animals. The group was everything. Getting separated from the group was probably the worst thing that could happen to an elephant ancestor. Hence the behaviour of holding on to the elephant in front of you was vital to survival. This was accomplished by holding on to the tail of the elephant in front of you. Since the elephant lacks hands it did this with its (then short) trunk.

A Japanese research group developed a computer model showing that elephants without trunks would frequently collide with each other. This because the lack of space to react to the movements of the elephant in front. A longer trunk would result in trunks and tails getting caught in the thick undergrowth. The current trunk length seem to be optimal in Indian elephants which still have the jungle as their major habitat, and varied more in the African elephant which can be found in more open landscapes.


Professor at the UOL

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