Editing 1398: Snake Facts

{{comic
| number    = 1398
| date      = July 23, 2014
| title     = Snake Facts
| image     = snake_facts_new.png
| titletext = Biologically speaking, what we call a 'snake' is actually a human digestive tract which has escaped from its host.
}}

==Explanation==
The comic lists a few '{{w|factoid}}s' about snakes, ranging from the mildly informative to the strictly tongue-in-cheek. The first factoid references the hypothesis that {{w|snake venom}} was an evolutionary development of {{w|saliva}} that, over time, gradually became more toxic as snakes with saliva that was able to assist in subduing their prey possessed an evolutionary advantage.  It then posits that the evolutionary branch that developed into venomous snakes began with a snake whose mutation gave him a mouth that was 'slightly more gross than usual'.

The second factoid references the 'longest snake in the world', citing a South American habitat.  Given the habitat listed, it is possible the comic is referring to the Green Anaconda ''({{w|Eunectes murinus}})''. But the Green Anaconda, while an impressive creature and one of the longest snakes in the world (Wikipedia says, "reaching more than 6.6 m (22 ft) long"), is generally not as long as the Reticulated Python ''({{w|Python reticulatus}})'' of Southeast Asia (Wikipedia says "grow to 6.95 m (22.8 ft)"). The latter is generally recognized as the world's longest snake, though not its largest by mass.  Wikipedia lists numerous reports and measurements of much longer specimens of Anaconda, including the statement, "While in Colombia in 1978, herpetologist William W. Lamar had an encounter with a large female specimen which measured 7.5 m (25 ft) and was estimated to weigh between 136 and 180 kg (300 and 397 lb)."  The article indicates that reports of very large specimens cannot be considered as fully scientifically verified, and part of the humor of these "Snake Facts" is that they fall outside of scientific verification.  The factoid then states that the world's longest snake is 'believed to be over 60 years old'. As Anacondas generally do not live beyond 20 years in captivity, and likely less in the wild, the factoid appears to be in error on this count also. On the other hand, Anacondas are reported to continue growing throughout their lives, so a 60 year old female specimen (females are larger) would likely be the largest snake in the world.  Since there are so many exaggerated reports about Anacondas, this may be part of the joke.  Its wording seems intended to imply that the snake in question is not a ''species'', but rather a ''single specimen''. This information may be a parody of factoids, since one would expect to learn about the length of "the world's longest snake", not its age.

Additionally, the comic illustration accompanying the second factoid colors in a '{{w|habitat}} range' on a map of South America that is snake-shaped, possibly implying that when it states 'The longest snake is found in {{w|Brazil}}, {{w|Peru}}, and {{w|Chile}}' that this snake is so long that it literally stretches from Brazil, across part of Peru, into Chile, and that the 'habitat' shaded on the map is, in fact, this mammoth snake's {{w|silhouette}}.

The final factoid is entirely tongue-in-cheek, beginning with a typical factoid trope in which a collection of related items are laid end-to-end, then the length is compared to something else in a way intended to surprise the reader that the collection of items is indeed, so extensive (literally and figuratively).  For example, "If you laid all the veins and arteries in the human body end-to-end, they would stretch 60,000 miles".  The third factoid takes the form of that trope and turns it into a joke, "If you laid all the bones in a snake end to end, you would have a snake."  The resulting length would not be a surprise to anyone, as snake's bodies are long and narrow and thus their bones are roughly arranged 'end to end' already (at least compared to most other creatures).  Obviously, you would not have an entire snake, literally, but you would have a skeleton that was recognizably that of a snake and could reasonably be referred to as 'a snake', albeit a skeletal one.

The title text presents the amusing idea that 'snakes' as we know them are not, in fact, a suborder of reptiles but are instead human {{w|digestive tract}}s that, rather than being a system of organs, are creatures capable of escaping from their 'host' human and living independently.  The idea seems to follow from the superficial resemblance between snakes and the human digestive tract as long, roughly tubular collections of animal matter, which can process the food entering the top end, and getting rid of the waste in the other end.  Actually the human digestive tract is essentially a hole that runs through the body, closed off most of the time only by {{w|sphincter}}s, and digestion thus can be said to take place outside the body.  Nutrients are absorbed across membranes via osmosis, active transport, and diffusion.

==Correction==
*Randall had previously posted an incorrect map, that included the snake's habitat in {{w|Bolivia}} instead of Peru. [http://www.explainxkcd.com/wiki/images/0/0e/snake_facts.png]

==Transcript==
:'''Snake Facts:'''
:Snake venom evolved from saliva, which means it all started with a snake whose mouth was slightly more gross than usual.
:[Picture of a snake below the text above] 
:Snake: Hi guys!
:Off-panel voice: Eww, it's Frank.
:[Map of South America with gray shade in the form of a snake. Text to the left of it] 
:The world's longest snake is found in Brazil, Peru and Chile. It is believed to be over 60 years old. 
:[Picture of a snake skeleton between the first and the second of the lines below] 
:If you laid all the bones in a snake end-to-end,
:you would have a snake

{{comic discussion}}
[[Category:Animals]]