Halfway down the road from the busy Bir id-Deheb crossroads leading to the pretty seaside resort of Birzebbuga, on the right hand side, one comes across a natural cave - Ghar Dalam.

Ghar Dalam must be one of the most important national heritage treasures; the serious studious visitor has before him, on reflection, a kaleidoscopic picture of the past history of Malta throughout the aeons of time.

To begin with, it was formed by the river which furrowed the valley and through cracks in its floor bed percolated and dissolved the underlying soft limestone and hollowed a tunnel-cave underneath it.

This was many millions of years ago; way before the 4000 BC of our unique megalithic free standing temples at Hagar Qim and Mnajdra and indeed many years before man set foot on these islands about 10,000 years ago.

On the other side of the picture in our time it served as an air raid shelter during the 1939-1945 war, also as an aviation fuel safe store for the Royal Air Force.

In our grandparents' time it was used as an animal pen by the local farmers but when it was opened up and explored an astounding amount of extinct animal remains and evidence of prehistoric human activities were uncovered.

It has to be kept in mind that North Africa-Malta-Sicily-Europe were joined together by a land causeway in prehistoric period and the rushing river waters mentioned above washed and pushed along the animal remains into the tunnel-cave under its floor bed.

When the cave was excavated and its contents examined in the 19th century, the investigators came upon remains of deer, bear, wolf, fox, mice, shrew, otters, birds, bats, giant tortoise and hippopotamus and elephant!

All authorities appear to agree that at some period the sea levels receded and left the Maltese archipelago as a series of stepping stones between Africa and Europe. The elephants and other animals were trapped and isolated; the food became scarce and the elephants became stunted in body build and became dwarf elephants!

In my young student days I was told time and time again how this scarcity of food had engendered a reduction of the noble elephant size to this dwarf size. I accepted this hypothesis without question but for decades now I have felt uncomfortable with this facile explanation. And I have reached a point when I have to get it out of my system by putting before the reader two biological examples.

Firstly, in the equatorial forests of Africa there have been for ages past tribes of dwarf persons, the so-called forest people pygmies. There is no shortage of food there and the dwarf structure of the pygmies has not been attributed to a lack of food as far as I am aware.

Secondly, on the opposite side of the coin, the present noble horse, an animal which dwarfs his human masters, originated in North America as an animal with short legs and not much bigger in size than a dog and again no one has suggested, always as far as I know, that an abundance of food changed this doggish stature to that of the horse as we know it now.

In conclusion therefore I feel uncomfortable to believe that these two diametrically morphological changes in stature to "dwarf" and "giant" forms respectively is to be attributed to the factors of scarce and plenty foodstuffs. The answer I feel is in the genes.

The defence rests.