The novel also details a brief encounter with a giant snake, estimated by Challenger to have been over 50 feet long. Though not based on any known snake at the time, its inclusion likely came from reports by Fawcett. In 1907, Fawcett claimed to have witnessed and killed a giant anaconda of a similar size, though his report was unverified. However, the 2009 discovery of "Titanoboa" fossils, which could fit the description given in the novel, indicates snakes of gargantuan size did indeed exist in prehistoric eras.