Sketches of Natural History of Ceylon eBook

J. Emerson Tennent
This eBook from the Gutenberg Project consists of approximately 590 pages of information about Sketches of Natural History of Ceylon.

Sketches of Natural History of Ceylon eBook

J. Emerson Tennent
This eBook from the Gutenberg Project consists of approximately 590 pages of information about Sketches of Natural History of Ceylon.

Still, sea-snakes, though well-known to the natives, are not abundant round Ceylon, as compared with their numbers in other places.  Their principal habitat is the ocean between the southern shores of China and the northern coast of New Holland; and their western limit appears to be about the longitude of Cape Comorin.  It has long since been ascertained that they frequent the seas that separate the islands of the Pacific; but they have never yet been found in the Atlantic, nor even on the western shores of tropical America.  And if, as has been stated[1], they have been seen on a late occasion in considerable numbers in the Bay of Panama, the fact can only be regarded as one of the rare instances, in which a change in the primary distribution of a race of animals has occurred, either by an active or a passive immigration.  Being exclusively inhabitants of the sea, they are liable to be swept along by the influence of currents; but to compensate for this they have been endowed with a wonderful power of swimming.  The individuals of all the groups of terrestrial serpents are observed to be possessed of this faculty to a greater or a less degree; and they can swim for a certain distance without having any organs specially modified for the purpose; except, perhaps, the lung, which is a long sac capable of taking in a sufficient quantity of air, to keep the body of the snake above water.  Nor do we find any peculiar or specially adapted organs even in the freshwater-snakes, although they can catch frogs or fishes while swimming.  But in the hydrophids, which are permanent inhabitants of the ocean, and which in an adult state, approach the beach only occasionally, and for very short times, the tail, which is rounded and tapering in the others, is compressed into a vertical rudder-like organ, similar to, and answering all the purposes of, the caudal fin in a fish.  When these snakes are brought on shore or on the deck of a ship, they are helpless and struggle vainly in awkward attitudes.  Their food consists exclusively of such fishes as are found near the surface; a fact which affords ample proof that they do not descend to great depths, although they can dive as well as swim.  They are often found in groups during calm weather, sleeping on the sea; but owing to their extreme caution and shyness, attempts to catch them are rarely successful; on the least alarm, they suddenly expel the air from their lungs and descend below the surface; a long stream of rising air-bubbles marking the rapid course which they make below.  Their poisonous nature has been questioned; but the presence of a strong perforated tooth and of a venomous gland sufficiently attest their dangerous powers, even if these had not been demonstrated by the effects of their bite.  But fortunately for the fishermen, who sometimes find them unexpectedly among the contents of their nets, sea-snakes are unable, like other venomous serpents, to open the jaws widely, and in reality they rarely inflict a wound.  Dr. Cantor believes, that, they are blinded by the light when removed from their own element; and he adds that they become sluggish and speedily die.[2]

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Sketches of Natural History of Ceylon from Project Gutenberg. Public domain.