THE TARANTULAS 125 



been struck from its nest. Mme. Merian's report (which was re- 

 ceived with considerable skepticism, since it was not believed at the 

 time that any vertebrates could be consumed by spiders) was later 

 followed by many claims that birds, lizards, and other animals were 

 habitual prey of the great tarantulas and even of other smaller spi- 

 ders. Corroboration of the early stories came in 1863 from H. W. 

 Bates, in his book The Naturalist on the River Amazon. This tal- 

 ented observer actually saw the capture and killing of one of two 

 birds that were attacked, and very accurately depicted the spider in 

 the act of feeding on it. Since that time, the debate has been con- 

 cerned with the question of the capability of the spider actually to 

 make use of the body of the vertebrate as food, not with its ability 

 to capture it. 



That a powerful, predaceous creature, armed with strong fangs 

 and potent venom, can kill a bird, a mammal, a snake, or a lizard is 

 not an astonishing thing. The arboreal tarantula cannot differenti- 

 ate between a bird or -a large insect, and makes its capture in exactly 

 the same manner by springing upon it and striking it with its fangs. 

 Spiders predigest their food by flooding the wound with secretions 

 from the maxillary and other glands, softening the tissue so it can be 

 sucked into the body. The powerful buccal secretions are known 

 to have a digestive effect on meat, so it is not strange that even the 

 bodies of vertebrates can be taken through the small mouth open- 

 ing. A tarantula can reduce the fat body and wings of a large satur- 

 niid moth to an insignificant vestige, and do so thorough a job of 

 it that one wonders if chitinous outer parts were not absorbed 

 along with the softer portions. It can reduce the bulk of a fat mouse 

 or the body of a small rattlesnake in the same way, feeding on the 

 gruesome corpse for many hours. 



In the United States the lessened opportunity to capture small 

 vertebrates has kept our tarantulas largely insect eaters a quite 

 different situation from that in Brazil, where the ground-loving 

 species of Granrmostola and Lasiodora are believed to kill and feed 

 on frogs, lizards, and small snakes in their natural surroundings. 

 In captivity, these large spiders definitely preferred such small cold- 

 blooded animals, and would generally pay no attention to various 

 insects offered as food. While experimenting on spider venoms, 

 Drs. Brazil and Vellard of Sao Paulo kept fifty of the tarantulas in 

 good health for eighteen months on a diet of frogs, lizards, and 

 snakes. Small rattlesnakes and the venomous Eothrops were killed 

 and eaten as readily as any other kind of snake. 



