The Evolution of the Giraffe

pation... :)))


Wrote a draft of this before the silence...

Well, the unusual topic of  "What the heck are those little knobs on a giraffe´s head for" came up again the other day - Truly, I had nothing to do with it, It just came up :)
Once it did come up though, I felt gratified to be able to provide an intelligent answer:

The modern giraffe (or garden variety if you live in Africa - They really are liable to turn up in your garden there...) that we are all familiar with is, as science tells us, the result of a very long chain of evolutionary "selection" processes.
The secret to those funny little knobs on their heads would be clearer to most people if one of their very near relatives had not become extinct around the end of the seventeenth century. Much like the Dodo on Mauritius, the "Madagascan Micro Giraffe" became extinct at the hands of man...

These diminutive creatures were more closely related to the modern giraffes forebears in that they were very small and not very elongated! Try to picture a creature about the size and shape of a Chihuahua (yes, the little dog), but it has the same camouflage pattern of the giraffe... except that it is in a dark green colour rather than brown. And of course, it has those funny little knobs on its head too (although they are larger in proportion). Yes this is a strange looking little beast indeed. However this creature was perfectly evolved to live in its natural habitat - The vast Broccoli woodlands of pre-colonial Madagascar!
In the days before the colonization of Madagascar, The plains were covered in sparse woodlands (not dense forest) of broccoli. The broccoli was grazed by small family groups of the micro-giraffes (usually a couple of adults and their offspring). Because the broccoli was sparse, the giraffes were vulnerable to attack (mostly from the co-evolved giraffe eagle) and they of course evolved defensive camouflage to minimize this risk. The camouflage pattern we are familiar with, but the colouring was green to blend in with the broccoli. If we now imagine these micro-giraffes in amongst the broccoli heads, and we imagine that at the first sign of danger, they freeze motionless and close their bulging little eyes ... With those knobs on their heads, they just seem to blend in with the surrounding broccoli heads...
And so we can now see where the knobs come from.

The giraffe from the nearby mainland of Africa that we are now all familiar with has evolved further after the island of Madagascar became separate from the continent. This was due to the changing climatic conditions, and as the broccoli grew and changed with the climate, so did the giraffes - As the country became more arid, the broccoli grew more sparse and deeper rooted to find the deeper water table. Likewise as conditions got harder, the only broccoli to survive the voracious feeding from the giraffes, small though they seem, were the plants that grew taller than they could reach. The giraffes also evolved and thus elongated, and the colour of their coats adapted to match the more arid climate, but those little knobs remained. Till we have the situation we see in Africa today with giraffes grazing on the sparse acacia trees of the African savanna (Acacia trees are directly related to Broccoli!) and still having funny little knobs on their heads - There was apparently no selective pressure for the knobs to de-volve.

Back to the story of the Madagascan giraffes... Alas, when the island was colonized, the Europeans were quick to spot the bounty of the vast broccoli woodlands and they set about harvesting the crop without regard for sustainability, as was the usual story in that era. Within a few decades, the wanton destruction of the micro-giraffes habitat had given rise to the giant economic broccoli empires that would just as soon disappear as their natural resource was tapped out. The poor micro-giraffes were of no economic value at all and were simply hunted to try to preserve the broccoli, and eventually they died out in obscurity when their habitat was gone. Another sad story of man's thoughtless conquest of nature.

And there you have it, the origin of those knobs on the giraffes head.

p.s. Credit must also be given to Mike and Jason (former co-employees with me) for assisting in the uncovering of this most interesting evolutionary tale.