Monitors may be natural inbreeders… [Archive]

Steeve B

12-03-04, 10:24 AM

First let me say that iv never studied them in nature and have never even seen them in nature, however many captive behavioural observations broth me to this conclusion, aim sharing my tots with you in hope that someone will shed more light on this subject. Expressing my tots in English so that everyone can understand my concept is quit unlikely, however ill give it my best trying not to omit any valuable information’s. Monitors start as eggs in a nest, even though we do not fully understand nesting, we do know about temps humidity and general egg husbandry, now hers some of my views, I think growing foetus can produce some heat, this allowing the middle eggs to stay a few degrees higher, possibly acting as sex determination, this natural process is altered when we separate eggs and place them side by side in incubators, next when eggs hatch I believe IMPRINTING is a key to varanids survival, many animals have a window of about few minutes to a few hours where IMPRINTING happens, usually imprinting is a maternal bond, however I believe it’s a social bonding tool for monitors, this allowing them to grow as a commune and eventually pair bonding and reproducing, there are some advantage for young monitors to grow in such commune safety being primary. Many things can bring us to this thinking, years of trying to pair up WC, or raising young WC monitors in pairs or group only to see them kill each other after a brief separation, same clutch monitors in general can be separated and reintroduced at will, even CB from deferent clutches are more difficult to mix. If we applied this logic to wild monitor populations, then most copulations are from siblings or from dominant males (father) as most intruders are aggressively chased away.
Pleas consider this as thinking out laude, contrary to many folks aim not afraid to be wrong.

Ps. I also think that inbred birds and reptiles can evolve and adjust to ever changing habitat faster
:)

Cake

12-03-04, 11:07 AM

I am not sure if you are correct in saying that inbreeding would allow a species to evolve faster to a changing environment as it would bring about the expression of deleterious recessive alleles.

An alternate hypothesis to your imprinting one is that they imprint their siblings so as not to mate with them. They would not fight with one another due to their relationship with them in the fact that they share 50% of their genes with them. Their indirect reproductive gains are increased if they do not kill thier siblings, and further increased by killing unrelated individuals of the same sex.

Do your observations take into account whether the individuals are of the same sex?

Also is there TSD in monitors?, if so, is it species specific?, Is it type 1, or type 2?

I do not mean this as a slam, rather to incite debate and conversation.

Steeve B

12-03-04, 11:35 AM

Excellent its always fun to have a different view.

The following are by no means exactitude and may be outdated tomorrow, but for now there has never been any documented negative effects in inbreeding varanids, even though multi generation have been produced, some studies claiming inbreed syndrome are actually incubation and parental care faults.

Your alternate hypothesis makes sense but doesn’t correlate with my observations, I will surly keep these information’s in mind while I keep researching this matter.

Yes my observations includes both sex throughout development.

I don’t think TSD is significant with varanids, however I have reasons to believe ESD especially humidity plays an important role in sex determination, what I still need to learn is how a mass of eggs in a properly selected nest, is affected or can hold moisture (humidity levels can vary inside out of the egg mass)

???

Jeff_Favelle

12-03-04, 12:29 PM

After 100's of thousands of years of possible line/inbreeding in the wild, perhaps deliterious recessive allels have been "weeded out"?

And I think Steeve's theory may just apply to snakes, even more so. Anyone who has ever gone snake "hunting", knows very well that there are hot spots and pockets of snakes within the population. And obviously, they don't travel great distances, soooo what do you think may occur?

Good stuff. I totally agree, and have said so for years! :D

Steeve B

12-03-04, 06:23 PM

As I said many things led me to this conclusion and some aren’t monitor related, as Jeff stated snake can show us more about varanids then we may think!
Aim particularly interested in large pythons egg clutch, the way they stick and form a large mass, iv took temperature measurements in many clutches with females and the center was always warmer and drier then the outside, that’s with the female rapt around them, but this cant be conclusive as the data will vary from one set up to the next. Also theirs a variable with large pythons that correlate with my views, its blood pythons, each part of the year importers get only one sex then get animals of the opposite sex later, iv seen a similar trait in shipments with dumeril’s and beccari’s but not 100% like in blood’s.
This says a lot about how humidity can affect sex determination, I believe species with smaller clutches will have more chances to produce same sex animals, but then again they can produce many clutches at different time of the year, I who’d dough that species with 40+ eggs would produce all the same sex, this would have no value in nature as these species have little chance to double clutch and often will only breed biannually.
So there you have it! This is how I came to the conclusion the an egg mass surrounded by an insulating medium in a stable environment will manage its temp and humidity to the species advantage.

crocdoc

12-03-04, 10:37 PM

The temperature dependant sex thing is fairly easy to figure out: separate eggs from the same clutch and incubate them at different temperatures and/or humidities. I'm not into python breeding, but as it's been going on in captivity with some regularity for some time I'd be surprised if no one tried this, yet.

As far as monitors in the wild regularly breeding with siblings, speaking purely theoretically, it would be an extremely odd strategy from an evolutionary standpoint - reducing genetic diversity ultimately leads to extinction. Although there hasn't seemed to be any problem with captive monitors being inbred over the 10 or so years they have been bred with any regularity, that 10 years pales when compared to hundreds of thousands, if not millions of years.

Secondly, part of the problem with extrapolating captive behaviour to wild monitors is the assumption that conditions are the same in captivity as they are in the wild.

In the current instance, the assumption is that monitors that don't get along kill each other, therefore the need for an evolutionary tendency for sibling bonding to prevent this. In captivity, two monitors placed together may sometimes kill each other, because they can't get away from each other. In the wild, they wouldn't be near each other to start with, unless one of them was cycling or there was an abundance of food nearby (in which case they'd be concentrating on that and ignoring each other). If they didn't like each other, they'd move away from each other. Even if one gave chase, the other would likely get away. Even when one is cycling, they have the leisure of checking each other out slowly in the wild, rather than being locked in together.

The second thing is how we remember the data. We'll remember every time someone loses a monitor to an attack by another because it is such a shocking thing, but we forget the number of times animals are introduced that get along without a hitch. Unrelated animals killing each other is not the norm or we'd never risk introducing them. It's something that occasionally happens.

There is also the likelihood that two animals being introduced are unrelated: pretty high since related animals would usually be housed and raised together. Only in unusual circumstances would we raise siblings apart then reintroduce them and, even under those circumstances they'd recognise each other's smell.

It seems natural that animals get along better if they are raised together, but that's mostly habituation. If you wanted to keep a dog and a cat in the same house, for best results you'd raise them together from puppy and kitten rather than introduce them as adults in the confines of a room. It's not a reflection of what goes on in the wild, much as our captive monitors habituating to us isn't, either.

kap10cavy

12-03-04, 11:30 PM

Thats pretty much fits into what I have seen with my savs.
I have 2 that have been together for a number of months and get along great, although the smaller one will show his dominance on occassion. I recently got another and slowly introduced her to the others. I have had to remover her because the other two seemed to team up against her and she has a strong feeding responce, so things were going to get ugly.
She now has her own cage and spends her time eating, basking and trying to find a way out. Maybe one day I will find her a fella to keep her company.

Scott

Jeff_Favelle

12-04-04, 04:53 AM

reducing genetic diversity ultimately leads to extinction.

Not in all cases. Mutations happen all the time, adding more alleles to the "pool", and if all recessive deliterious alleles are weeded out, then there's no problem of them lining up due to inbreeding.

However, if the habitat changes, a genetically-low population is at an extreme risk. But I would never say that low genetic diversity leads to extinction. Nature is much too complicated for a bold statement like that.

Siretsap

12-04-04, 07:49 AM

Originally posted by Jeff_Favelle
Not in all cases. Mutations happen all the time, adding more alleles to the "pool", and if all recessive deliterious alleles are weeded out, then there's no problem of them lining up due to inbreeding.

However, if the habitat changes, a genetically-low population is at an extreme risk. But I would never say that low genetic diversity leads to extinction. Nature is much too complicated for a bold statement like that.

The problem with the low genetic diversity is it has the bottle neck effect, it will continue till all the genes are exactly the same (alsmot like each animal is a clone from the other). I know that there are some types of mamals that have this problem (certain wild cats). If all were to have the same gene pool, then as soon as one would contract a virus and can't overcome it (cause if you talk about inbreeding, then you mean all the animals from this species are in the same area and no where else), then you risk extinction. So yes in a way inbreeding does cause extinction.

lostwithin

12-04-04, 08:55 AM

From what I have read and learnt genetic diversity is what allows a population to evolve, many natural safe guards have evolved along with species to help avoid inbreeding within populations.
I am certain it does occur in wild populations but if it were to become more then a random event it would surely lead to a species eventual evolutionary demise. Genetic mutations do occur and that would add some variability into a population but it does occur enough that it would introduce any significant amount of variation, any first year biology text could explain it much better then I.
In then end it has been shown in many studies that diversity is the key to evolutionary success, of a species. Inbreeding causes less and less diversity bringing a halt to the evolutionary process.

That is the reason species don’t inbreed if it can be helped the cause of this lack of attraction to family members is beyond my capabilities of explain. In theory if reptiles were "hotwired" to actually do the opposite and there drive was to increase inbreeding there would be no diversity, they wouldn’t have evolved into he species that occupy almost every corner of the habitable world.

Now as a final argument I will use plants as an example, just to show how plants avoid inbreeding at all costs, I don’t know if there are any others with significant knowledge of botany but plants have evolved several amazing methods of avoiding inbreeding, In some flowering species the genotypes of pollen are detected and any that originated from related flowers are stopped before they reach fertilization. There are other way that plants avoid inbreeding I just found this one most fascinating. In the end the point is every living thing is hardwired to avoid inbreeding, as it eventually leads to the demise of a species.

Devon

Steeve B

12-04-04, 10:57 AM

Not so long ago I use to call every ackies (little mongrels) even if all looked healthy, I guess it was stubbornness on my part, refusing to envision other possibilities including possibilities that have been dismissed as otter nonsense, anyhow for this I started looking at reptiles breeders around the world, the funny thing is all of them have produced several generations of inbreeding with as many species and none have experienced inbreed syndrome. Iv talked with amphibians breeders colubrides boas pythons turtles tortoise lizards and plenty of bird breeders (these are the closes to varanophil) what have I learned from them? Plenty, first the more experienced think nothing about inbreeding, in this group you have very knowledgeable peoples, one in particular is a dna blood specialist (sorry don’t know the term) anyway he’s been and endless source of information to me, Hers a question? Who knows how proteins and sugar and all vitamins and minerals can affect blood? Ad to this individual metabolism and environments, you now have an infinite variable. Its next to impossible that different animals synthesise these the same way.

Next; captive monitors behave the way there species evolved, sure they are confined but they use inherited behaviours, these behaviours are millions of years old and passed by genetic, this even before they evolved into separate species on different continents, why do you think they all have somewhat similar body language similar threat display courtship and nesting, you have termites nesters in Africa, Asia, Australia and all these species can if they need too! Nest in the ground or in trees, This is inherited behaviour to me.

Perhaps what I most enjoy about these forums is the endless information’s we exchange! How boring it would be if we all tot the same way.

kap10cavy

12-04-04, 11:24 AM

A simple reason why I don't believe inbreeding will lead to extinction. Reptiles were here before we were. They were doing this then and will be doing this long after we are gone. I am more concerned with habitat desrtuction than some lizards that pretends to live in the moutains of West Virginia.
Maybe someone will teach them to play the banjo.
Maybe thats why we like them so much here in the south. Hahaha

Scott

Cake

12-04-04, 04:02 PM

A great deal of prefessional breeders intentionally inbreed their animals to express recessive alleles (Take BP's for example). In captivity the genetic diverstiy of the species is not of a great concern as they do not need to evolve to changing conditions. The genetic diverstiy of a natural population needs to be more variable, as these species are still subject to natural selection and not artificial as with captive animals.

mbayless

12-04-04, 05:51 PM

Scott,

If you inbreed with your sister you will see traits good and bad compounded = and that is why in many states, maybe not Tennessee it is illegal to marry your sister, but of course in others it is encouraged! (haha).... these negative traits often cause full term births to abort, or in varanids: perhaps cause a DIE scenario (full term baby die-in-egg!)? Think about it...Darwinism encourages genetic diversity, and if you reduce this diveristy, you move toward extinction!

Cheers,
markb

Scales Zoo

12-04-04, 07:01 PM

Further on Jeffs posts about snakes in the feild.

Rattlesnakes out here, leave their dens in the spring, go up to 20 miles (30 kms) away, and come back and go down the exact same hole that fall. They also breed at these den sites, and near by rookeries.

There was a study done in Texas that I was reading about.

A lot of rattlesnakes were raised seperately for 3 years. There were 2 groups that were related, and then 1 group of unrelated snakes. They were all microchipped. In 3 years time, after never being around one another, they were all dumped in a large room together. The family groups paired up, and the ones not related were searching around the room, or laying by themselves.

My guess is Rattlesnakes, and many other snakes, do inbreed for generation after generation. Maybe they are doing it on purpose. After weeding out the bad alleles, maybe they have an advantage over most other types of life that have not.

Ryan

Jeff_Favelle

12-04-04, 07:29 PM

If you inbreed with your sister you will see traits good and bad compounded

Humans have not had natural selection working on them for millions of years to weed out deliterious recessive alleles. Most reptiles in the natural world have. I don't think you can draw comparisons between us and wild animals. We're due for a catastrophic die off. No question. Too much outbreeding? Doubt it. More like too much medicine (creating super bugs) and too much of the weaker getting to breed. Why do you think there are more cases of all the "syndromes" every year. Every single person is kept alive. There is no survival of the fittest in humans. Its survival of EVERYONE. The human race gets significantly weaker every generation. More in some areas than others. But culturally, its impossible for us to evolve. Our sociology won't allow it.

http://www2.uic.edu/~vuletic/top7.html

http://www.aepryus.com/evolizer/BioPaper.html

Tim_Cranwill

12-04-04, 08:11 PM

Amen! It's so true... :)

Steeve B

12-04-04, 09:15 PM

Ryan excellent exemple, Thanks!

mbayless

12-04-04, 10:01 PM

Hi Ryan,
Good post. I might say: Medicine has altered the gene-pool significantly for the last 50 or so years now. Since Amniosyntesis, genetic afflictions like 'X-factor', 'Downes', 'pin-heads' etc.... can be diagnosed and aborted before they are born; it is phenotype/genotype modification. Premi-kids are born at 5-months now, where-as when I was born at 6 months 4+ decades ago, they told my mother "He'll be dead in a week, have another kid" - so technology has altered the "Survival of the Fitest" so that fit/non-fit can live and pass on genes too...but eventually, it all works out in the end. You can play with 'Mother Nature', but you cannot 'MESS' with her! She is a tempermental Lady!

MN keeps trying to mess with us: SAARS, now Avian-China flu H-5 which is potentially catostrophic if it spreads like 1918-19 flu pandemic! If it does, it could wipe out a billion people! (somehow that does not sound so bad really....).

cheers,
markb

crocdoc

12-04-04, 10:08 PM

I think there are still a few crucial points being missed here:

1. almost every animal ever studied has shown inbuilt mechanisms to prevent inbreeding. Why jump to the conclusion that monitors are the exception because they get along together when raised together (as do cats and dogs)?
2. No matter how inbred our captive reptiles are, reptiles have been bred in captivity with regularity only in the past 20 or so years. That simply does not compare to the millions of years we are talking about in evolutionary terms.
3. mutation works at way too slow a rate to accomodate rapid adaptation to change. Monitors are a very adaptable group and have radiated quite well: there are a lot of species all close enough to still be considered a single genus - this indicates fairly rapid evolutionary change rather than them being static (as you'd expect if they were genetically identical, which they'd pretty much have to be once they've weeded out all recessive deleterious genes - which would be near impossible, anyway)
4. some crocodilians (smooth fronted caimans, for example) use termite mounds to nest against, for warmth in their rainforest habitat. Crocodilians are more closely related to birds than they are to lizards, so the use of termitaria may or may not be an independantly evolved habit. Either way, it doesn't really add to the story.
5. has anyone actually looked at the DNA of rattlesnake populations to see who is mating with whom? It's likely that snakes from the same den will share certain smells (they'd be from the same locale), but are they chosing close relatives from the same den or the least related individuals? A recent thorough study of cunningham's skinks (which hang out in colonies of related individuals) has shown that they go to great lengths to avoid inbreeding. Had no one checked the DNA of adults, youngsters and neighbouring colonies, casual observation would have lead to the conclusion that they were inbreeding.
6. What would be the evolutionary incentive for monitors to inbreed intentionally, being probably the first ever animal to be proven to do so? If it is to avoid being killed by mates, we are assuming that wild ones kill each other the way captives sometimes do, which is not a likely scenario. A study done on the reproductive biology of lace monitors had a very stable population of breeding adults in the study area. The only animals that died were roadkilled.

So, why would they need to inbreed if it is evolutionarilyy advantageous for them to outbreed? Anyone?

mbayless

12-04-04, 10:20 PM

In a confined space, in captivity, breeding among juveniles, adults, whomever, wherever occurs in higher (and perhaps) lower vertebrates as well! Inbreeding could be a artifact of captivity, and anyone who has taken a biology class or has common sense can see it is not a natural act among higher vertebrates or of Mother Nature's devine scheme of things.

Mankind has made it taboo, and a for good reason. Look at the British Royal Family lineage, and it is full of inbreeding, crossbreeding, and they have Monarchs with mental illness (Nicholas I, Russia; King Gustav V, Sweden), bleeders (H.R.H. Prince Alexey Romanov, Russia; H.R.H. Leopold II, Belgium), and a plethora of other maladies spread throughout Europe due to their inbreeding practices....

Cheers,
markb

crocdoc

12-04-04, 10:33 PM

... but aside from the reasons inbreeding is usually considered 'bad' from an evolutionary point of view (that's usually a given), I'd like to know what advantages an animal could gain by going 180 degrees in the other direction: ie intentionally inbreeding. Rather than discuss the 'whether' (whether they do or don't - which could be tested by someone with a grant), perhaps I'd have a better understanding of the other side of the discussion if I knew the 'why'.

mudflats

12-04-04, 10:51 PM

First off this is probably one of the most informational posts, glad this was all discussed.
One issue i have seen was one of my favorite herping spots, a single ditch only brought to have water by the rain, and was miles away from any other water bed etc... They where around 15-20 florida water snakes in this ditch. That alone is a prime example of how inbreeding does not affect snakes.

Scales Zoo

12-04-04, 10:59 PM

I'll have to try to find the other thing I read about rattlensnakes, but this is about that study.

http://news.nationalgeographic.com/news/2004/02/0223_040223_rattlesnakes.html

DK, I don't think anyone has done DNA studies yet - and I shouldn't speculate about inbreeding because of family bonds. The above article did mention female snakes showing "family bonding" more than males.

Would be interesting to study, to see if the snakes are inbreeding, or if males go find females in dens miles away. Rattlesnakes, alone - are like monitors. They are so unique, but so little is really known about them.

There was another study on rattlesnakes about the rattling of tails causing static voltage, and possibly turning the snake into an electro magnet. The studiers assumed it may help them to find water, or food. I have to wonder if this might not help them travel 20 miles from a hole, and come to the same one in the fall. Heat pits, a rattle, venom, the ability to articulate each fang independantly like a finger...... one of the coolest reptiles out there for sure.

Ryan

crocdoc

12-04-04, 11:19 PM

Originally posted by mudflats
First off this is probably one of the most informational posts, glad this was all discussed.
One issue i have seen was one of my favorite herping spots, a single ditch only brought to have water by the rain, and was miles away from any other water bed etc... They where around 15-20 florida water snakes in this ditch. That alone is a prime example of how inbreeding does not affect snakes.

Unfortunately, mudflats, finding a group together like that does not necessarily indicate inbreeding until someone finds out how much mixing there is with other populations. Someone I know put a transmitter on a diamond python living in the suburbs of Sydney - it inhabited a treed reserve between suburban streets and was assumed to be isolated. In the breeding season, it attracted seven males, which clearly came from far and wide. Things are not always as they seem from casual observation.

Even if your small cluster of water snakes were inbreeding, we'd still only be talking about a limited number of generations rather than thousands

crocdoc

12-04-04, 11:25 PM

Ryan, thanks for the link to the article. Unless I read it incorrectly, it isn't suggesting that they inbreed, but suggesting that they hang out together with related individuals (in the study, it was related females that were hanging out together, not males and females). This would make them like the cunningham's skinks I mentioned above, which hang out in family groups. Now someone needs to test the DNA of the offspring to check against that of the parents to see if related rattlesnakes are inbreeding, or if they have mechanisms to prevent this, as do the skinks.

Steeve B

12-04-04, 11:38 PM

Dk I really like your insight, its always mind-bending for me. I wish I hade answers to all your questions, but I don’t, all I can offer is my own vision based on my understanding. Herpetoculture is the science of reptiles husbandry, in this we are following the foot steps of great man’s, many you know the work better then me, you once expressed in one of our exchange you embraced Darwin’s theory on evolution of species, Then you must know that his work on the Galapagos lives on today, His very own foundation punched not once but twice into his own theory by the discovery of inbred finches developing larger more adapted beaks and the cross breeding of land and marine iguanas. This says a lot, reptiles do what they need to survive, inbreeding out breeding crossbreeding are all survival tools.

Mark;
I have much respect for you and love you as a brother, pleas stop embarrassing me and stick to the subject.
Ps. Pinhead is a syndrome of rapid growth, its got nothing to do with pre-birth
:)

crocdoc

12-05-04, 12:01 AM

Actually, the finches are an excellent example of why animals need genetic diversity to adapt. A population of finches reached the islands, where there were still many niches left unfilled. The finches radiated and formed a whole species group filling the niches.

It is possible this was accelerated because they were isolated, inbreeding and therefore recessive genes were expressed which included bill shapes and size ts. The important factors, though, are that:

1. the inbreeding was forced through isolation
2. the birds landing on the island weren't all genetically identical from thousands of generations of inbreeding and therefore had the genetic diversity amongst them to produce the many finch species we see there today.

As far as the iguanas go, that's typical island stuff: a population gets isolated on an island and quickly becomes a new species through boatload or founder effect. Again, this is forced inbreeding, not an inherited behaviour.

mbayless

12-05-04, 12:07 AM

Steve: You do not say the truth, as your past actions do not agree with your words here.

Pinhead: It is a genetic - female recessive trait malady where the family members exhibit microcephaly. It often is common in families, much like the 'Lobster-hands' malady. My Mother studied such people in Denmark 1947-1949, some of whom had been in the English-banned film "Freaks" (1935). They were terribly ******** and often die young. Macrocephalic persons are also short-lived ******** due to opposite conditions.

Inbreeding has been seen in scenarios of isolation, confinement and related conditions, as seen in captive reptiles, mammals, etc....so is it natural? Or a natural reaction to an artificial/harsh/stressed conditions?

I do not know of your report on Galapagos inbreeding finches, unless you are speaking of "The Beak of the Finch" By John Weiner. Ecophysiology and microhabitat and food availability were factors determined there on how/why the Darwin Finches' were evolving in a 20 year cycle...it is a fascinating book.

markb

Jeff_Favelle

12-05-04, 02:59 AM

I'd like to know what advantages an animal could gain by going 180 degrees in the other direction: ie intentionally inbreeding. Rather than discuss the 'whether' (whether they do or don't - which could be tested by someone with a grant), perhaps I'd have a better understanding of the other side of the discussion if I knew the 'why'.

If the local environment is in a state of stasis (unchanging) and the local fauna have evolved for thousands (millions) of years to exploit their respective niches to the fullest, being reflected in their genomes (obviously), then how is introducing genetic diversity going to help them? Obviously it would help them against unwanted change (adaptation purposes) and possibly against disease ("possibly"), but that's only if the environment changed. And that's only if disease was introduced. Nature ain't quick. Disease just doesn't "happen" (rare), unless some funny bi-ped animal (us) causes it directly or indirectly. Adding new genes that aren't capable of exploiting the local niches (microhabitats) better than the next set of creatures isn't condusive to keeping the stasis. It will create unbalance.

And this is the very core as to why is a BIOLOGICAL NO-NO to release animals even 1 or 2 km from where they are collected. Ever wonder why all the books on reptile collecting suggest to release the animal(s) PRECISELY where they were found?

Nature is complicated. Saying that inbreeding is ALWAYS bad and serves no purpose because its based on HUMAN cultural influences is just as bad as saying that everything should be inbred and that genetic diversity is evil. Every case is specific and we cannot begin to understand the complexity to make those decisions with what we currently understand. That's why we try to preserve what we have in the here-and-now. If genetic diversity was so great across the board, then why aren't all the scientists catching animals from different metapopulations and releasing them into others. More gene flow, more diversity, it would great!!

Nope.

crocdoc

12-05-04, 03:29 AM

Originally posted by Jeff_Favelle
If the local environment is in a state of stasis (unchanging) and the local fauna have evolved for thousands (millions) of years to exploit their respective niches to the fullest...

That's a nice big 'if' - in fact that's a massive 'if' - but where on earth are you going to find such a stable, unchanging environment? Certainly not in Australia, where the largest radiation in varanids has occurred. How would such a radiation occur if all of the monitors were so inbred as to reduce genetic diversity, anyway? Why aren't they all one, homogenous species? Perhaps they speciated ages ago, before developing this tendency to inbreed and it is just a massive coincidence that the popularity of monitors as pets is occuring at the end of monitor radiation, while they are at their most diverse in terms of numbers of species but are going through their stable, non-changing period? Or perhaps they have breeding patterns like every other animal on the planet and are still evolving?

Originally posted by Jeff_Favelle

And this is the very core as to why is a BIOLOGICAL NO-NO to release animals even 1 or 2 km from where they are collected. Ever wonder why all the books on reptile collecting suggest to release the animal(s) PRECISELY where they were found?

The reason it's a no no to release animals away from where they were caught is because there are differences between one locale and the other. That doesn't mean that all of the animals in one area are so inbred as to be genetically non-diverse, it just means that they share certain traits in common. If I caught a diamond python tomorrow, drove a few hours north or west and released it, I'd be releasing it into carpet python country. That's a clearly visible difference, but the same thing happens on a smaller scale closer in. It's still a big leap of faith to go from recognising that there are locale differences to saying that they inbreed intentionally. Within any locale there are still large numbers of individuals so that they needn't be inbred to all be similar in some regards.

Originally posted by Jeff_Favelle
Nature is complicated. Saying that inbreeding is ALWAYS bad and serves no purpose because its based on HUMAN cultural influences is just as bad

I am not saying inbreeding is always bad because of human cultural issues with it, I'm saying that there is no evidence of any animal in nature that intentionally inbreeds for any reason, and I don't think monitors are going to be special in that regard, either. What happens in captivity is another story altogether and I have no issues with that. The current thread is about whether or not monitors specifically seek out siblings as mates.

Originally posted by Jeff_Favelle
If genetic diversity was so great across the board, then why aren't all the scientists catching animals from different metapopulations and releasing them into others. More gene flow, more diversity, it would great!! Nope.

Genetic diversity is great, but the reason scientists don't do what you are suggesting is because they recognise that locales differ.

I'll give you an example: Sumatran tigers are on their way out. Last I heard there were fewer than 40 individuals left in the wild. It's starting to get to a point where loss in genetic diversity will cause long term issues with this race of tiger. No scientist would suggest capturing a few of the more common Bengal tigers and introducing them to Sumatra, for as much as it would introduce more genetic diversity it would destroy the integrity of the locale (in this instance a subspecies, but not all locale specific populations have differentiated to that point).

crocdoc

12-05-04, 03:55 AM

Originally posted by Jeff_Favelle
If the local environment is in a state of stasis (unchanging) and the local fauna have evolved for thousands (millions) of years to exploit their respective niches to the fullest, being reflected in their genomes (obviously), then how is introducing genetic diversity going to help them? Obviously it would help them against unwanted change (adaptation purposes)

Getting back to this point, I should mention that 'not being bad' is usually not enough of a selective pressure for a behaviour or phsical trait to evolve. In other words, for monitors to have gone to the complete opposite of all other animals by becoming intentional inbreeders, they wouldn't do it because it will not harm them in an (at this point mythical) unchanging environment. There'd have to be some sort of positive selection going on to change behaviours that pointedly. i.e. there would have to be an advantage for them to develop such a breeding pattern. What advantage would that be?

By the way, the reasons it isn't good to release animals away from where you find them aren't only about locale/genetic issues, but population dynamics. Wild animals have home ranges, territories, burrows etc (depending on the species) and throwing and animal into an environment far from home could wreck things for it and/or its neighbours.