I was reading recently about how there have been reports of anacondas up to 120 feet in length, but no specimens over 30 feet have ever yet been verified to exist.
That got me to wondering, though, if there is in theory any reason to believe snakes can’t possibly grow that long. Animals that walk on legs are limited in size by the square-cube rule, but snakes don’t support their bodies with legs. Is there any reason to think a serpentine creature above a certain length is unable to sustain itself?
No cite here, but as the length of the snake increases, so does the resistance of the vasculature. The heart has to pump against this resistance, so I would imagine cardiac output would be a limiting factor to length.
A few. First off you have to consider weight. A 20 ft anaconda alone can weigh over 150 lbs and the longer they get, the heavier they get as well. Even though an aquatic lifestyle can compensate for huge body mass, it doesn’t do so without serious modifications to the body plan of an animal.
All constrictors are ambush hunters, and need to be able to move at great speed to catch their prey, a huge fat slow animal is going to have a difficult time managing a fast strike.
Really big anaconda only eat every few months anyway, and the rate of growth is extremely slow by that point. Herpetologists generally accept a possible length of up to 35 feet for anaconda, but even that length is quite unlikely.
It might be possible but unethical to modify an animal when young so that it’s pituitary glands keep producing in overdrive to produce a specimen with a form of gigantism or acromegaly to see what the theoretical limits might be. Such an animal would probably be prone to a host of other issues though.
Kinda true, but actually, if you look at the way both venomous and constricting snakes attack their prey, what they do is to coil up a bit and lung with only the front part of their body. The midsection and tail may not move at all during this process, so it wouldn’t necessarily be a hindrance if it was considerably larger.
I would ask you to rethink the use of “unethical” here. A friend, Dr Ralph Brinster did some ground breaking work in this area, creating “giant” mice. His work has furthered scientific knowledge that will one day make gene therapy commonplace.
Dr Brinster is amazing, and the closest I’ll likely ever come to chatting with a genius.
His work was even mentioned by Time Magazine, and he is a veterinarian!
Fair enough, but he had a goal in mind. Just messing with animals to see how big you could get one without any further goal might be a teensy bit more questionable though.
Actually, I stand by my earlier post after reading the article. While I think that the work he has done will be of great significance to us, I can see no application to growing an anaconda twice the size of the usual varieties. We aren’t talking about a 1 lb mouse here, we are talking about a potential for a 40-60 ft , around 800-1200lb snake. Most likely one with a voracious appetite since it will be stuck in a sort of permanent growth explosion. During their peak growth years, the young green anacondas I cared for often took 3 large rats a week, then bunnies, then chickens, until they reached about the 10 ft mark and their appetites slowed down. Scale that up by twice and your “juvenile” super-conda is easily eating two dogs or goats a week, with the potential to consume adult humans by it’s third year. Such an animal as posited above really would be nothing more than a freak, and a dangerous one at that.
Okay, I’m invoking a corollary to Doper Rule #7: Just like cats, you are not allowed to say “‘giant’ mice” in a post without linking to pictures of said “‘giant’ mice”!
If increasing length also means increasing cross-sectional area, then a limitation similar to that which applies to legged animals will eventually come into play, since a snake’s body must have some internal structural integrity.
If we were to lengthen a snake without thickening it, it would become more likely to snag on things or tie itself in knots.
Natural selection against pointless energy costs is also a major factor.
See here for some interesting information on the largest fossil snakes. Gigantophis is the largest for which there seems to be good information, and the most recent analyses peg it at up to 10 % larger than extant snakes. However, it seems to be very questionable whether snakes larger than this have ever existed.
