A LOST WORLD

Evening Star, Issue 21810, 28 August 1934, Page 5

A LOST WORLD

LAKE RUDOLF ISLAND SIGHT OF THE REPTILE AGE PREHISTORIC PLACE Man lias been lord of creation so long that it is difficult for him to picture a time when the struggle was not between man and the animals, but between the ponderous reptiles and the more agile mammals (writes W. S. Dyson, in the ‘ Manchester Guardian ’). Yet there are a few out-of-the-way places left which are still in the reptilian stage of zoological'development, and one such place is the Central island of Lake Rudolf. A recent visit to this island for the purpose of collecting zoological specimens as part of the work of the Lake Rudolf Rift Valley Expedition provided :m opportunity to see something of what existence must have been like when the first step towards mammal-liko reptiles occurred.

This small volcanic island is four square miles in extent and lies some six miles from the western shore of the lake, its craters have been active within recent geological times. Even now steam and sulphur vapour still escape from vents and fissures in the ground, while the presence of a total of fourteen dead craters, three of which arc now “ crater lakes,” gives further evidence of the island’s volcanic ox-igiu. These lakes, the largest of -which is half a mile in length, are separated from Lake Rudolf by narrow strips of laud over which crocodiles pass backwards and forwards.

The crocodile is lord of the water, although turtles, which grow to a large size, treat them with scant respect. Apparently the turtles are safe from attach within their shells; As many as fifty crocodiles may be seen at a time sunning themselves in the brackish water of the crater lakes, their evil heads projecting expectantly. It is difficult, to know what they feed oii, fertile fish within _ the island lakes can hardly be sufficient to support this large reptilian population. The birds ana turtles that feed near them apparently do not fear danger from them. MONITOR LIZARDS. The supremacy of the reptiles is not confined to the water, for on the land monitor lizards, some of them six feet in length, take the place of mammalian carnivora in other districts. These slow-moving primitive creatures arc so confident that they defy man merely by spitting and snapping at him in the same way as their ponderous ancestors must have done in ages gone by. It is fascinating to watch these lizards as they dig for crocodile_ eggs in slow, deliberate fashion, their Jong, purple tongues flashing in and out like flame from the nostrils of some medieval dragon. MONITOR LIZARDS, The prehistoric atmosphere created by the presence of these antediluvian animals is enhanced by _ the chaotic land formations among which they live. The cone of land which is the central island rises to a height of six hundred feet above the soda-chargcd water of Lake Rudolf—tunnelled from above by craters as might be rotten wood by beetle grubs. If ~dne”stands'_ at the bottom of these craters, with the steamy heat rising in- solid wisps above the steep cliffs which form the crater rim, watching the log-like heads of crocodiles as they lie inert on the scummy surface of the lake, hearing the long-drawn sigh as they exhale the foul air from their unlovely bodies, one only needs to imagine the soaring pterodactyl replacing the busy cornier-; ant to take one back to the days when new land was appearing from the vast primeval swamps. Even the rank smell: of decomposing vegetation . must, have been the same then as now. There are no mammals on the island except hats. But some small lizards of the Lacerticlfo family' exist—offspring, presumably, of some fortunate ancestor which, borne to the island by a bird of prey, escaped to reproduce its kind. SPECIALISED. j The birds alone show that finalspecialisation', which . Countless ' generations have produced. Those quoor birdsthe “ skimmers,” whose- curious, tazor--1 ike hills w-ere noted by Darwin in his ‘ Voyage of the Beagle,’ nest on the island. Birds of the tern family, they have a bright orange beak compressed laterally, the lower part longer than the upper and widening at its base. As their name implies, the “.skimmers” fly along the surface of the water, the tip of the lower beak just submerged, sending up spray as from the prow' of some small vessel. How such a bill could be developed to catch the small fish which is their food is a puzzle. Countless cormorants also nest on the island—interesting birds for their regularity of habit; each day at sunrise they: set off for the mainland in a constant stream, like city-bound inhabitants of suburbia, and return at night with the same monotonous regularity, spoonbills; On the steep cliffs round one of the more desolate lakes the-spoonbills have their nests. These birds lay large eggs, white with orange speckles at one end,' on rocky ledges, scantily protected by a few' sticks. The roughness of the shell rather suggests that the large soda content of the lake water has altered its composition. Indeed, most of the birds of Lake Rudolf are represented on Central-Island. Two-notable exceptions for which it is difficult to account are the duck and flamingo. The birds, then, share the island with the reptiles; besides being of interest in themselves they are of especial interest as the agents by w'hich most of the plants must have gained a footing on its barren shores. The insect_ world is well represented but irregular in distribution, depending on powers of flight. All those useful scavenging beetles common in Africa are absent, while butterflies, and tree locusts are fairly frequent. The unique interest of living in the middle of a large-scale experiment in genetics is not obtained without certain discomforts, ami after a week of an unbalanced diet (to say the least) and of drinking water the addition of wdiieh of citric acid merely turned one noxious drink into another, one is glad to return to the comparatively modern province of Turkana.