Reptile & Amphibian Forums

Your thread got my attention!!I remember hearing about a female Burm at a zoo giving birth without breeding too! I'm just wondering if it's a built in survival mechanism? Let's say 1 female snake washes up on a remote island,the only one of her kind for many years,she gives birth to male offspring.....and the species continues!It's only an idea,I'm not a scientist!LOL!!

there is a snake on an island coast of costa rica where females have one hemipene that is not functional and is thought to be just that. I believe it is a yellow lance head but I could be wrong. As far as other cases of parthenogenesis I really have no idea. I would think it is more of a freakish occurance or cells dividing. I would say this because it is not by any means a "normal" way of reproduction in higher vertibrates like snakes. There are lizards though who are all female because of such an example. Their parthenogenic births are clones of the mother which is not possible with snakes. I would also be curious to see more research being done on hermaphroditic syndroms in snakes. 1 in 100 human births differ from standard male or female with klineflter syndrom being true hermaphrodites with ovotestes.

Hey eunectes4 I think you are talking about the golden lance head. I have always wanted to go see those things. There is only like a couple zoos of have them.
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Justin

np

let me throw in my tid bit of information that i have found over the years. turtles can breed one season and not lay eggs for years and then they fertal eggs for 7 years with out breeding agein. whiptail lizards are clones being that there are no males and only females give birth. this is a very bad thing for them to do being that if one gets sick they all get sick being there all the same. look at the garter snake when they come out of there dens the female is chased and breed with many many many males and the female chooses the sperm of the best males and males are starting to evolve to make the sent of a female so that all the males will chase him and he will run them round then mate with the female. just a little info i like to throw out there. just to try and answer some of the questions.

CrazyCody
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I'm CrazyCody KadunkKadunk!!! I'm a herp god!!!

Kadunk was here

CrazyCody

If I remember right, one of the links I posted before concerning this topic was about the burm you mentioned. I believe it was in the Netherlands zoo. Maybe not but I know it was definately in europe.
Your 'floating to an island' scenario has some points to it. When discussing island species and people claim that they drifted there on driftwood or something, it would seem that two animals (male and female) would have had to have drifted at almost the exact same time. Although sperm retention in a female could account for some sucessful colonizations I bet 99% of animals caught on a drifting piece of debris perish at sea. So the chances of even one animal doing it are already very remote and then you add into that the possibility of another animal of opposite sex doing the exact same thing within the relatively short life span of the first one, you have astronomical odds against it.
Given the very wide range of animals that have colonized islands, supposedly in this manner, I am still wondering if this ability (parthenogenesis) is inherant in all herps. We have observed it in only a few species, as mentioned before, but to create the right trigger mechanism would be really hard to do in a study.
Right now I am forming an opinion that it almost has to be an inherant trait among all herps, or at least a big percentage of them, for the varied amount of animals that do colonize islands a great distance away.

Remember we are talking about millions of years in evolution with herps. Parthenogenesis is a primary means of reproduction in a lot of species and mainly invertibrates. I would have to agree with Kelly when he said it is such a random and rare occurance (although it is increasingly recognized). Snakes are a high enough class of vertibrates where sexual reproduction is pretty much the standard across the board. The part where I get a little stuck on was first believing parthenogenesis is an occurance from the past and is slowly evolving in the opposite direction. But after reviewing most cases, this would certainly make no sense. About 95% of cases I have heard of and an even higher percentage of true documented cases are in new world pit vipers. There really isnt anything higher evolved than that. So maybe it is an ability that every herp potentially has with varying degree among species but I still have to lean toward "not with snakes". Like I said before, they are pretty high vertibrates for asextual reproduction. Cells divide and weird stuff sometimes happens. If wierd stuff like 1 in 100 human births differ from standard male or female and there are plenty of cases of klinefelters in the highest of all vertibrates and mammals at that I would not put it past a bunch more weird stuff going on with snakes and not look at it as any kind of ability.

I agree that it has been observed more so in new world pit vipers. It has also been observed in old world pythons as well. i.e. the case of the burmese. These two snakes are so far apart that you have to come to the conclusion that it can occur in all herps, snakes included. Since it is such a rare occurance and documented cases so few there is not enough info to determine a conclusion as to what species of snakes would have the ability and which wouldn't. I still say that if you have documented cases from those two opposite ends of the snake world you would be more apt to assume that it would be possesed by everything in between the two, which is a lot of snakes.
Since no one knows for sure what the 'triggering' mechanism is that would cause this it would be impossible to just start keeping snakes isolated their entire life and if they didn't produce offspring then they must not have the ability.
Sexual mutations are more common then most people think, I agree. Since we as humans are all females when embryos it makes sense that a TON of things could, and do, go wrong.
I would like to think that a complete necropsy was performed on all animals involved in these cases to rule out any hermaphrodidic (I don't even think that's a word lol) or other genetic cause.
Again I'll say that if a burm and a rattler can do it then ALL snakes are fair game for it.

My 2 cents,
Arik

I was re reading my post above and I did not mean to say that we are all females genetically I meant to say we all start with female genitalia as embryos. The chromosomes that determine sex are still present in males but they have not started to change their female parts to males yet.
Arik

That is different though. Hermaphriditic syndroms have nothing to do with not developing further. Rather chromosomal differences such as xxy, xxxy, xyy, x0 (not all are hermaphriditic but are gender related). xy androgen insesitivity is the only one I can think of that resembles not having further development from being a female. But these females have testes somewhere..you just cant see them because their cells regect androgen which is what makes males bodies look like they do with hair and all the muscle and they develope to look like a female with no hair and very female bodies. But this is a 1/40,000 thing while I mentioned 1 in 100 still differ from standard male of female. I agree that it is likely all snakes have the potential to reproduce by parthenogenesis but I do not see it as an ability but rather an occurance due to irregular cell division. I also read that article on the burmese and do not recall a very good conclusion.

I think my use of the word 'ability' was misleading. It seems that we are in agreement. I should have used the word 'potential'.

Arik

Parthenogenesis in vertebrates typically only occurs in small, isolated populations were there has been a very stable environment for an extended period of time. The rapid loss of genetic fitness usually excludes the evolution of parthenogenetic populations under other ecological conditions. This is mainly due to a parthenogenetic population having a very slow genetic response to environmental change and because it also allows the accumulation of deleterious mutations at a much higher rate than within a sexual reproducing population. I don’t believe that parthenogenesis has ever been found associated with an entire isolated population of snakes, but only in one or two individuals within a sexually reproducing population. With snakes, it appears to be more of a meiotic error than anything else. This is how I see it anyway.

Kelly

I agree that 99% of animals that finds themselves adrift do indeed persish. If they do survive the trip then the odds of a compatible mate also rafting to the same island becomes fantastically less likely... but an immutable law of nature, as put forth in Peter Tyson's "The Eigth Continent", is that "given enough time, the most improbable becomes a certainty".
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"Nothing happens in contradiction to nature, only to what we know of it."