The House Gecko

Article by Torben B. Larsen

I doubt that there is a house or a flat in Dhaka which is not inhabited by somewhere between one and a dozen House Geckoes (Hemidactylus frenatus). They climb our ceilings, walls, and windows, they hide underneath our wall-hangings and curtains, and nearly all of us have strong feelings about them – we either love them, or we hate them. But love or hate, we all wonder how they manage to run across the roof and up and down the windows.

Geckoes form a family of highly specialized lizards, some 600 in all, mostly shy, nocturnal creatures hiding away in tropical forests. Even an avid naturalist like myself who spends months on end in the forests of Africa do not see many of these elusive and well-camouflaged creatures. But I am not alone in this. I once met a Swedish scientific gecko-collecting expedition in an airport on my way to Kenya; ten days later I met them by chance near Mombasa and they had just a dozen species to their credit after fourteen days.

No such problem with the House Gecko which are so common. Actually this should be House Geckos since in each of the tropical areas one species of Hemidactylis threw in its lot with us. All the House Geckos are so similar that only experts can tell them apart.

The House Gecko must have begun its relationship with us back in the early days when one of the first cave-men said to his wife: ‘Look dear ... why don’t you stay in this cave most of the time. You go collect nuts and fruits, but when you get home, light a fire so that the bad bears and sabre-tooth tigers don’t attack you’. So next time Mr. Cave-Man went on a business trip with his colleagues in order to spear a mammoth or two, his wife built her fire.

The cave was warm and comfy – the smoke at times a bit much. The kids loved it and stopped complaining about the cold, so Mrs. Cave-Man (yes, I am afraid they used genderist language at the time) had time to sit down and think of new and better ways of preserving all the fruits and nuts she collected (this later became the Mars Bar).

On the wall, next to the fire, appeared a gecko. It, too, loved the cave. Not only was it warm and pleasant, but all sorts of insects were attracted to the fire – and insects are the gecko’s primary food. And there was a further advantage; inside the cave none of its usual predators would follow. This was beginning to look like a very good deal indeed.

And it was indeed a good deal. Today, some 12,000 human generations after Mr. Cave-Man, the gecko is still with us. And I would guess that at least two-thirds of all the insects they eat are now those attracted to electric light. There must be millions of people who did NOT get dengue fever or malaria because the gecko ate the mosquito that was heading for them. I personally love geckoes; and I would insist that those who do not should at least give them the respect due to someone who managed to live with 12,000 generations of humans – after all, in my country, most humans cannot even manage a lifetime marriage.

A House Gecko clinging on to glass It took a long time before it was finally decided how geckos manage to run upside down on the ceiling and up and down windows. The most popular explanation was suction cups under the feet. In fact, the feet are covered with millions of tiny hooks, so small that they can cling on to the slightest imperfections on the surfaces the use. And even the finest piece of glass reveals itself under the microscope to be hardly polished at all.

Photos included in the article:
Click to enlarge