The World's Biggest Snakes

The Highly Doubtful 37.5 Foot Green Anaconda

During most of the last half of the 20th century the longest snake was considered to be the Anaconda, (Eunectes murinus) because of a record that became known as the Dunn-Lamon record. In 1944 Emmett Reid Dunn, a well known and respected herpetologist published an article on the reptiles of Columbia in the journal Caldasia. It included a statement that his friend, Robert Lamon, a geologist working for the Richmond Oil Company had killed and measured an 11.5 meter anaconda in eastern Colombia. Raymond Gilmore, of the US Fish and Wildlife Service, investigated this record, in 1954 he found Robert Lamon working for the Northern Natural Gas Producing Company in Calgary, Alberta. In a letter dated May 19th 1954 Lamon wrote to Gilmore and stated that he did kill and measure an anaconda on the Meta River. In that letter he stated the following.

I remember measuring the beast with a four-meter stadia rod and if my memory serves me right it required almost three lengths of the rod to obtain the dimensions but I could not swear to this in that it may have been almost two lengths of the rod. However, this occurred sometime in about 1939 or 1940 just before I met Dix Dunn in Colombia. Therefore the measurements must have been fresh in my mind and if I so reported it to Dunn I feel confident that the 11.5 meters is correct.

Gilmore wrote in his unfinished manuscript the following. The 11.5 m Anaconda was widely cited as the documentation that the longest snake was in fact the Anaconda. The record was cited by Oliver (1958), Pope (1961), Minton and Minton (1973) and in numerous popular references including several encyclopedias. Unfortunately, Gilmore’s letter went unpublished and unrecognized. After his death, the letter and unfinished ms were deposited in the archives of the San Diego Natural History Museum where Gilmore had been Curator of Mammals. Van Wallach, then at Harvard University obtained copies of the files, and in the early 1990’s sent them to me. In 1993 I published them in the Bulletin of the Chicago Herpetological Society.

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