Through the Brazilian Wilderness. Roosevelt Theodore
us was far more active than the yellow lachecis venom. Then each snake was returned to its box unharmed.
After this the doctor took out of a box and presented to me a fine, handsome, nearly black snake, an individual of the species called the mussurama. This is in my eyes perhaps the most interesting serpent in the world. It is a big snake, four or five feet long, sometimes even longer, nearly black, lighter below, with a friendly, placid temper. It lives exclusively on other snakes, and is completely immune to the poison of the lachecis and rattlesnake groups, which contain all the really dangerous snakes of America. Doctor Brazil told me that he had conducted many experiments with this interesting snake. It is not very common, and prefers wet places in which to live. It lays eggs, and the female remains coiled above the eggs, the object being apparently not to warm them, but to prevent too great evaporation. It will not eat when moulting, nor in cold weather. Otherwise it will eat a small snake every five or six days, or a big one every fortnight.
There is the widest difference, both among poisonous and non-poisonous snakes, not alone in nervousness and irascibility but also in ability to accustom themselves to out-of-the-way surroundings. Many species of non-poisonous snakes which are entirely harmless, to man or to any other animal except their small prey, are nevertheless very vicious and truculent, striking right and left and biting freely on the smallest provocation—this is the case with the species of which the doctor had previously placed a specimen on the table. Moreover, many snakes, some entirely harmless and some vicious ones, are so nervous and uneasy that it is with the greatest difficulty they can be induced to eat in captivity, and the slightest disturbance or interference will prevent their eating. There are other snakes, however, of which the mussurama is perhaps the best example, which are very good captives, and at the same time very fearless, showing a complete indifference not only to being observed but to being handled when they are feeding.
There is in the United States a beautiful and attractive snake, the king-snake, with much the same habits as the mussurama. It is friendly toward mankind, and not poisonous, so that it can be handled freely. It feeds on other serpents, and will kill a rattlesnake as big as itself, being immune to the rattlesnake venom. Mr. Ditmars, of the Bronx Zoo, has made many interesting experiments with these king- snakes. I have had them in my own possession. They are good-natured and can generally be handled with impunity, but I have known them to bite, whereas Doctor Brazil informed me that it was almost impossible to make the mussurama bite a man. The king-snake will feed greedily on other snakes in the presence of man—I knew of one case where it partly swallowed another snake while both were in a small boy's pocket. It is immune to viper poison but it is not immune to colubrine poison. A couple of years ago I was informed of a case where one of these king-snakes was put into an enclosure with an Indian snake- eating cobra or hamadryad of about the same size. It killed the cobra but made no effort to swallow it, and very soon showed the effects of the cobra poison. I believe it afterward died, but unfortunately I have mislaid my notes and cannot now remember the details of the incident.
Doctor Brazil informed me that the mussurama, like the king-snake, was not immune to the colubrine poison. A mussurama in his possession, which had with impunity killed and eaten several rattlesnakes and representatives of the lachecis genus, also killed and ate a venomous coral-snake, but shortly afterward itself died from the effects of the poison. It is one of the many puzzles of nature that these American serpents which kill poisonous serpents should only have grown immune to the poison of the most dangerous American poisonous serpents, the pit-vipers, and should not have become immune to the poison of the coral-snakes which are commonly distributed throughout their range. Yet, judging by the one instance mentioned by Doctor Brazil, they attack and master these coral-snakes, although the conflict in the end results in their death. It would be interesting to find out whether this attack was exceptional, that is, whether the mussurama has or has not as a species learned to avoid the coral-snake. If it was not exceptional, then not only is the instance highly curious in itself, but it would also go far to explain the failure of the mussurama to become plentiful.
For the benefit of those who are not acquainted with the subject, I may mention that the poison of a poisonous snake is not dangerous to its own species unless injected in very large doses, about ten times what would normally be injected by a bite; but that it is deadly to all other snakes, poisonous or non-poisonous, save as regards the very few species which themselves eat poisonous snakes. The Indian hamadryad, or giant cobra, is exclusively a snake-eater. It evidently draws a sharp distinction between poisonous and non-poisonous snakes, for Mr. Ditmars has recorded that two individuals in the Bronx Zoo which are habitually fed on harmless snakes, and attack them eagerly, refused to attack a copperhead which was thrown into their cage, being evidently afraid of this pit-viper. It would be interesting to find out if the hamadryad is afraid to prey on all pit-vipers, and also whether it will prey on its small relative, the true cobra—for it may well be that, even if not immune to the viper poison, it is immune to the poison of its close ally, the smaller cobra.
All these and many other questions would be speedily settled by Doctor Brazil if he were given the opportunity to test them. It must be remembered, moreover, that not only have his researches been of absorbing value from the standpoint of pure science but that they also have a real utilitarian worth. He is now collecting and breeding the mussurama. The favorite prey of the mussurama is the most common and therefore the most dangerous poisonous snake of Brazil, the jararaca, which is known in Martinique as the fer-de-lance. In Martinique and elsewhere this snake is such an object of terror as to be at times a genuine scourge. Surely it would be worth while for the authorities of Martinique to import specimens of the mussurama to that island. The mortality from snake-bite in British India is very great. Surely it would be well worth while for the able Indian Government to copy Brazil and create such an institute as that over which Doctor Vital Brazil is the curator.
At first sight it seems extraordinary that poisonous serpents, so dreaded by and so irresistible to most animals, should be so utterly helpless before the few creatures that prey on them. But the explanation is easy. Any highly specialized creature, the higher its specialization, is apt to be proportionately helpless when once its peculiar specialized traits are effectively nullified by an opponent. This is eminently the case with the most dangerous poisonous snakes. In them a highly peculiar specialization has been carried to the highest point. They rely for attack and defence purely on their poison-fangs. All other means and methods of attack and defence have atrophied. They neither crush nor tear with their teeth nor constrict with their bodies. The poison-fangs are slender and delicate, and, save for the poison, the wound inflicted is of a trivial character. In consequence they are helpless in the presence of any animal which the poison does not affect. There are several mammals immune to snake- bite, including various species of hedgehog, pig, and mongoose—the other mammals which kill them do so by pouncing on them unawares or by avoiding their stroke through sheer quickness of movement; and probably this is the case with most snake-eating birds. The mongoose is very quick, but in some cases at least—I have mentioned one in the "African Game Trails"—it permits itself to be bitten by poisonous snakes, treating the bite with utter indifference. There should be extensive experiments made to determine if there are species of mongoose immune to both cobra and viper poison. Hedgehogs, as determined by actual experiments, pay no heed at all to viper poison even when bitten on such tender places as the tongue and lips and eat the snake as if it were a radish. Even among animals which are not immune to the poison different species are very differently affected by the different kinds of snake poisons. Not only are some species more resistant than others to all poisons, but there is a wide variation in the amount of immunity each displays to any given venom. One species will be quickly killed by the poison from one species of snake, and be fairly resistant to the poison of another; whereas in another species the conditions may be directly reversed.
The mussurama which Doctor Brazil handed me was a fine specimen, perhaps four and a half feet long. I lifted the smooth, lithe bulk in my hands, and then let it twist its coils so that it rested at ease in my arms; it glided to and fro, on its own length, with the sinuous grace of its kind, and showed not the slightest trace of either nervousness or bad temper. Meanwhile the doctor bade his attendant put on the table a big jararaca, or fer-de-lance, which was accordingly done. The jararaca was about three feet and a half, or perhaps nearly four feet long—that is, it was about nine inches shorter than the mussurama. The latter, which I continued to hold in my arms, behaved with friendly and impassive