Reptile & Amphibian Forums

OK, OK, I know I am probably opening a can of worms on this and will get many laughs LOL!! However, I was wondering what are some thoughts out there on this concept with respect to reptiles. Are certain clutchmates simply produced to be decoys or sacrificial animals so the healthy viable offspring can escape predation and hopefully survive? I look at footage of baby sea turtles hatching and watch as the gulls and shorebirds swoop and take a ton of them. Are the ones taken exhibiting some type of behaviour that make them more prone to be selected, or is it just chance? Are they programmed to leave the nest earlier or later to fulfill their role? Same with crocodilian clutches. Some eggs and babies are snagged by monitors, racoons, etc. Are the ones selected done so because of something that makes them more appealing, or is it just a fluke and random? This occurs with many animals that congregate and migrate in large numbers as well. Think of the unlucky wildebeasts that get taken by crocs crossing the rivers!! Its also known that certain birds will give birth to two offsrping, with one dominating and eventually killing the other or pushing out the nest. Is the one destined to fail and feed/ward off predators as a calculated factor? Just some weird thoughts.

Do we catch and eat only the "special" fish?....I don't think so.....
But some fish do lay thousands of eggs due to the fact that many will not make it to adulthood.........

I think in snakes it is merely random and exemplifies the hierarchal food chain....

It is a hypothetical theory that would be hard to prove.
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John Lassiter
Poor planning and procrastination on your part does not constitute an emergency on my part...
www.coastalbendcaptivebreeding.com

Good point John. Oh yeah, my query is definitely hypothetical for sure. Just wondering aloud I quess, but curious if anyone on this forum may have studied it a bit or read something related to it. Just a fun topic to banter around??

No animal is born or hatches that doesn't want to survive. Not all may have the exact same abilities, preferences and luck, but all want to survive.

Back to your non-feeding babies subject, not one of those non-feeding hatchlings wants to die. If whatever they are looking for is in front of them (their unique preferences), they will respond. If not, they won't. And not all are necessarily the same in their preferences, probably a survival thing for the WHOLE population.
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Mark

My post above said nothing about non-feeding babies, or the will to survive giving proper choices. In fact, it has nothing to do with captive animals or captive husbandry. Based on your reply, I take it you disagree with the decoy theory. To be honest, I do too for the most part. Just blind luck one turtle was a bit slower than the one next to it when the gull swooped down. Still, I wonder sometimes. Not that it will ever happen due to expense and effort, but I wonder what a gut study done on the gulls that ate the hatchlings would determine regarding the health and viability of the eaten hatchlings. I know this sounds far fetched, but what if such a study showed the majority of the hatchling consumed were sexless, or had a defect that would have prevented them living much longer than they did? Same with reptile eggs that get eaten in the nest. Why some and not others? Are there possibly chemical or olfactory clues being given off from these eggs that entice the predators to eat them instead of the ones carrying viable embryos?? What if kinking in snake young were proven to be natures way to reduce overpurdened populations? What if more kinked and defective babies hatch out to be eaten when populations get too high based on available resources in the area? Just random thoughts LOL!! No right or wrong opinions on the subject.

>>... Just blind luck one turtle was a bit slower than the one next to it when the gull swooped down

or maybe the gull gets the faster one.

Isn't it possible a stronger, faster baby attracts the attention of the gull and is the one that's eaten (X many, in the example at hand)?

I think evolution is the result of a series of chance/random/accidental genetic events. Some increase the odds of survival of the species, and others diminish it. Survival of the fittest argues the individuals with the "improvements" will better survive and thus reproduce in greater numbers because they survived, eventually becoming more and more prevalent in the species' population.

But some evolutionary traits can lead to an animal's extinction, despite survival of the fittest ("survival of the fittest" applying not just to individual organisms, but to species, too--some species evolve and thrive, others take unfortunate genetic paths and are extinguished).

does that make any sense?

>>My post above said nothing about non-feeding babies>>

I know, I know - I just can't get past that earlier thread

So whats the next post gonna be about? Can't wait, lol. In all honesty, these are good discussions, so I do like what you've done here.
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Mark

Thanks Mark!! Not sure, but I will try to make it similar with no right or wrong answers, just a forum to hear folks thoughts and opinions on some matters.

What you are describing (decoy snakes) would be considered a form of altruism, which I do not believe is accepted by vertebrate biologists. Natural selection, even though it greatly effects a population of snakes in the long term, only works on the individual snake. There is no selective advantage for the individual decoy snake if his "role" is to get eaten. If he is eaten he fails to produce and is essentially a dead end.

OK, but what if his role IS to get eaten, fill the predators belly long enough so that viable healthy neonates can escape to secure habitate, survive, mature, and propogate? Dont get me wrong, or think I am disagreeing with you. I see the point where nature would not "waste" time making a worthless thing. But, what if its role as a decoy is worthwhile and advantageous to natures scheme for survival of those animals???

I would imagine this is important with clutch size. If all sea turtles survived, the ocean would be full of them. So some feed other animals, to allow some to succeed.

Compare brown watersnakes, up to 80 small offspring, to Rosy boas, 6 to 8 giant offspring. One must have a higher predator load then the other.

So here, genetics is effected by numbers produced to allow some to survive.

All the while each individual is carrying genotypic genetics that will become phenotypic if they survive. Cheers

I agree that larger clutch sizes are attributed to animals more likely to have their offspring preyed upon and that if ALL survived, there would be overpopulation. But, do you think some are purposefully predisposed to be preyed upon? Are some slower or brighter colored on purpose? Or, is it just a random free for all and all neonates on equal ground in regards to surviving?

Natural selection works on the individual, not the population. The end result can be profound impacts upon a population and populations certainly evolve, but only through selection pressures upon individuals within the population. Natural selection may favor female snakes that have a larg number of offspring, but that is obviously because the more babies they have, the more likely a few will survive to reproduce. It is not because some of the babies are preselected to serve as food for their siblings.

lol

I hear ya Joe. I stated this was a quirky post. Nothing to do with captive conditions, etc. Just looking for others views on what may be occurring in mother nature LOL!!!

>>...But, what if its role as a decoy is worthwhile and advantageous to natures scheme for survival of those animals???

I think this could devolve into a creationism v science argument. The suggestion of a "nature's scheme" suggests a big finger pushing animals around toward some end purpose--this one goes here, and gets eaten; while that predator's hungry, this one will go over there, and survive. Maybe "purpose" is the problematic term: my understanding of natural selection is that mutations occur by accident, but we laymen often use language that attributes intent or purpose. There's no purpose to that accident, though there may be a favorable outcome.

I see people say sometimes that (for example) a snake mimics a venemous snake's appearance "in order to" scare away predators. That again implies an intention, or purpose, when the fact is, as i understand it, over time a series of accidents resulted in an appearance that may diminish predation--it's a fortuitous outcome, but its usefulness can be judged only in the outcome (perhaps the first snakes that mutated and produced that unusual coloration would have been judged by observers to be harboring a harmful characteristic, instead).

I don't think i've been particularly articulate about this, but I'm hoping the point of accident vs intent or purpose or "scheme" makes sense.

Terry, your post has made alot of sense and I think you get the jist of the post. Your view is certainly plausible and articulated well. And that is what I wanted to hear, peoples views on the topic, not whether there is a right or wrong. Just views and why you have those views. Whether you believe there is a purpose, is no purpose, whatever. I threw this topic out because there was no inherent right or wrong responses. I was just looking for interesting conversation. Its just funny how it can turn into an argument or devolution.

Its actually a great question. One problem, in reality, sea turtles normally hatch at night and there are no seagulls around then. of course if they hatched in the day with seagulls around, that trait would be very limited.

Also, in nature, reptiles have a range of color and pattern, and behavior. This allows for some to fit in changing conditions conditions are always changing.

Some oddballs, have no or little change of surviving, like albinos. Others do, like the success of polymorphic snakes. Where color and pattern are not what allows them to survive.

After all is said and done, luck plays a very important part. or The individuals that make poor decisions, do not live to tell their stories(genetically) such is nature. Or even with poor years, where there is little production and no recruitment. As in, zero survive. Or supportive years where a high percentage survive.

Most of these animals have layers of behavior to deal with different conditions. If they did not, they would be gone. Fun stuff. Yet that does not prepare them for captivity. Cheers

FR, once again I state this post has NOTHING to do with captivity LOL!! Its just a "thinking" post if you will and the search for viewpoints (none being right or wrong) to the topic at hand, which is decoy animals in nature. So I take it you do not feel decoy animals are produced in nature. You either make it or not, and the ones that do make it pass along the genes (speed, coloration, etc.) to allow continuation of success at the game, correct?

Kev i believe it varies. In turtles it's more of a shot gun approach. So many are born some will have to make it usually. Who gets eaten is completely random. Of course weaker animals have a bigger handicap! It reminds me of sperm all trying to reach the egg, lol. Is it always the strongest that gets there? I don't think so. But the stronger ones have a better chance. In other animals like snakes for instance. Good instincts to hide and not be so obvious will go a long way. I don't believe there are certain animals pre-destined to die for the overall good of the upper class. It's like a shotgun a few pellets are gonna hit their target if you just aim in that general direction.
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King Snakes! Who can make a better mouse trap?
J Sierra

True. But are certain animals predisposed to being weaker because thats what nature wants?? Or, is it just random that one turtle was a bit slower than another at that particular time? I think its an interesting topic LOL!!

i'm going to have to agree with the "shotgun" theory. of course, it's beneficial for any clutch/ litter of any species to produce as many viable animals as possible. the stronger, healthier, and more likely to thrive each individual is, the better the enitre species will likely do in the long run.

but predation and other "negative" environmental factors will happen. therefore, it's beneficial for any specimen of any species to produce as many potentially viable offspring as it is environmentally possible to sustain, with the evolutionary "knowledge" that even some hardy specimens simply will not make it. turtles, crocodilians, and many other species produce large numbers of eggs for this exact reason. it's not so much to provide decoys (in my opinion, as is everything written in this post) as it is to scatter as many potential future breeders as possible. in millenia past, the individuals who produced fewer offspring failed to pass on their genes when large numbers of their offspring died young. the individuals more prone to producing mass clutches DID manage to get a few little turtles or crocs past the gulls and monitors, and the gene for larger numbers of babies got passed on.

however, i remain open to the possibility that certain factors, genetic or otherwise, may increase the likelihood that a baby critter could fail. but it would be REALLY difficult to study and conclusively prove a hypothetical factor that may or may not make a baby sea turtle more likely to be eaten by a gull (at least until baby turtles are hatched with bullseyes on their backs...).

I thought I said, in a sense there are decoys, in animals that produce large clutches, most of the clutch is to be consumed or doomed to failure. So those are the decoys. If these is X amount of predation, then the species must produce more then is being consumed to maintain a population.

There is also sexual differences as well, over the years, I have noticed there is far more DOR males then females. So I mentioned that to my friend. He skins DOR snakes. So he kept an eye on that, sure enough, over 90% of the roadkills are male, over a year, with all species. Yet we know that clutches are about 50/50. So this brings up your question, are these males decoys?

I do not think its an assigned task like with ants. Cheers

The "not like ants" statement was exactly the type of view points I was looking for and ants are a GREAT example of animals being assigned pre-determined roles and responsibilities in a colony or population!! As far as the DOR snakes being primarily males, well my opinion why has nothing to do with being decoys, just horndogs out cruising for love LOL!! Do you have any data correlating time of year this may be more prevalent, ie, spring breeding season vs. fall brumation preparation?? I would think it would be more pronounced in the spring when the males are actively seeking mates and more active in general.

The looking for love theory is getting weaker and weaker, as time goes by.

i do not know about all species. I have sure there are many reproductive stradgies amoung species and even amoung one species.

But, in all the species I have looked at. Males pair with females then attempt to stay with that female. Normally they gather in the fall, spend the entire winter, spring thru the gestation period with the female/s. In most cases, they choose a single female, but thats not a hard fast rule. They normally return to the same female, but that is also not a hard fast rule. So this causes me to question the roaming males that are looking for love. It appears they are looking to stay alive, then find love.

What you see on the roads are normally transient males, they are normally not large males, but young or small males. We call them gooners, as they tend to roam about not sticking to a defined range. My guess is, they are bounced from area to area, by the dominate individuals in that range, which includes both males and females. So they end up being the part of the population that is most likely preyed upon, or in your case, a decoy or better yet, they are the explorers that attempt to find new areas to expand into.

They are most commonly preyed upon. As they have no set range.

Most do not understand what a home range is for a pair/coloney, or individual. A home range must include areas to achieve the base tasks of any species. That is, include summer shelters, winter shelters, prey, water/humidity, the ability to escape harsh conditions such as floods, drought, fires, etc. With nesting or gestation sites being of prime importance.

Nesting sites/gestation sites are not just to hatch eggs, but are placed in areas that increase chance of survival. They not only include suitable temps and humidity, but are placed in areas where neonate prey is available.

Home ranges also include safe travel paths, so that the animals are not preyed upon easily. Once individuals find these areas, they claim them, by scent marking them and defend them against unwanted individuals of the same species or even other similar species. They also include members of the same specie to form pairs, groups, colonies, etc. And at time similar species.

Transients are easily identified by size and condition. They are generally in poor health, have high pathogen and parasite loads, and often scared up. Or found flattened on roads.

This is a subject we have been working on for decades. examples of populations are, in the groups I work, nearly every female is gravid nearly every year. finding gravid females on the roads is RARE. Large individuals are common at breeding sites or gestation sites, dens etc. Large individuals are rare on the roads.

Yes there are times when these populations move from one area to another, and if a road crosses their path, both males and females will be include in the DOR toll.

Gravid females regularly sit tight and do not move unless there is extreme stimulus to do so. So its rare to see them crossing roads, which is an unsafe pathway.

You are right about different individuals assuming different tasks. But they do not seem to be set to do that genetically. Its a case of bad luck, misfortune or poor years.

For instance, healthy populations are healthy because of a high neonate survival. This is not based on luck. They place their neonates commonly where they were born/hatched. They do so because of the known, they the adults survived to recruit, so there is a high percentage their offspring will survive. They follow success.

The gooners will reproduce if they are lucky, but their offspring survival rate is very low. As there is little support from the enviornment. Again, if they are lucky and find supportive conditions, they can establish new colonies.

One major support of this is the MDna testing of denning individuals. So far there is a trend that the population of a den originates from a single for a few females. I simply refer to them as family groups. We see these with all manner of reptiles, like many rattlesnakes, kingsnakes, etc etc , many lizards like gilas, varanids, iguanids, etc. Again, I am not saying all species do this, but I believe most species have a balance in the above range.

I have even seen denning of adults with such solitary species are coachwhips. These animals have a huge range so its hard to determine what the heck they are doing inside that range.

On the otherhand rattlesnakes not only have realitively small home ranges, but often call attention to themselves and are harder to overlook.

We have even seen this with torts etc.

I know, more then you asked for, but what the heck.

The problem is, what they choose to do is based on ethlogy(behavior) its behavior that drives speciation(often debated) The problem with behavior is it includes many layers and is not so predictable and repeatable. So science hates it and often ignores behavior. So, you tend to have trends, Some do this, some do not. What is key is, which parts contribute heavily to successful recruitment(recruitment is the difinition of success). DORS only contribute to vultures and ants, hahahahahahahahahahahaha So far, what occurs on roadways is not indictative of what healthy populations do.

Yes DORS include a heavy number of trasient individuals, which tend to be males, but again not always. Cheers

>>Its actually a great question.

Agreed. And your points are all good, Frank. I think when you say "individuals that make poor decisions" you're just slipping into casual language as we all often do, but it might create a misunderstanding in some people's minds about how evolution and natural selection occur: the individuals in these cases aren't making decisions, they are simply being acted upon by environmental and genetic events. Fair enough?

Actually poor decisions are what I meant,at least partly. Heres the part, Let me use a real example here. Pyros are saxocolis. Which I was told means, they use structures above the ground to live in, like rock outcrops, live or dead trees, etc. Lets just go with that for this example.

THey use the rock structures both above ground and below ground level, same for the trees, they use inside dead trees and into the root system.

After droughts, we have lots of dead trees, they will colonize these dead trees. Then whole areas are burned to the ground, actually into the root system. So the individuals that lived in dead trees are eliminated from the area, and those the chose rock outcrops that went into the ground lived to spread their genes. This occurs over and over.

These populations will again populate and move into other structures that may not have a long lifespan.

So here, where these snakes live, is based on the time and age of the area. Yes these things do change.

Another example of making poor decisions is those colonizing areas close to canyon bottoms. High water takes them out, the colony is re-educated to areas away from the canyon bottoms. This also goes forth and back.

I am sure there is some scientific term for this.

This also applys to populations along roadsides. The individuals that cross the road commonly, are taken out, the ones that do not are left to repopulate the area. Cheers

Its no fun when we agree!

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“Nothing is at last sacred but the integrity of your own mind.” Emmerson

WWW.TDSNAKES.BLOGSPOT.COM

I read an article recently which stated that toad tadpoles are not all created equal, but that some are weaker and therefore more likely to be preyed upon than their more robust siblings. This is a survival mechanism for the toad, who lays thousands of eggs at a time, but only a few make it to adulthood. Having some weaker individuals takes the predation pressure off the stronger ones. If I ever find this article again I will post the link.
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Bob/Chris
Pyromaniac AKA Greatballzofire

Wow!! Thats the types of info/thoughts I was hoping to get. I am surprised there may be something remotely supportive of the theory, but cool nonetheless!!

An event I witness frequently in my garden is the hatching of preying mantids. Inside the egg case are hundreds of tiny mantids. The first out prey upon their slower siblings. This gets the earlier to emerge ones off to a good start in life, since they don't have to go far to find their first meals.

With cannibalistic snakes possibly the same mechanism has evolved. For a tiny montane snake to actually catch its first lizard might be a daunting task, but if there is a slower weaker sibling right there in the nest, the opportunity to eat and therefore survive is increased exponentially.
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Bob/Chris
Pyromaniac AKA Greatballzofire

alright, you're driving down the street and 18 wheeler takes you out. Decoy, survival of the fittest (smart enough to look both ways), or just unlucky?

Now I see exactly why someone said this was headed for creationist vs evolutionary debate LMAO

Any/all of the above. Random chance matters some; if there's a drive by at work and I catch a round to the head that's (more or less) random.
If I'm playing in the middle of a shooting range and get shot that's natural selection
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We wouldn't have 6 and a half billion people if you had to be beautiful to get laid.
6.6 African House snakes
3.2 reticulated pythons
.1 corn snake
4.2 Florida Kings
1.2 speckled kings
1.2 ball pythons
0.0.1 Argentine boa

>>Any/all of the above.

That's minus the decoy theory though - your two examples were 1) random and 2) survival of the fittest

I'm still looking for a decoy example.

(besides a couple members of this forum

The only way I can find a way to have the word DeCoy fit is if its assigned to the transient part of all populations. They are normally doomed to failure.

I would guess that normally 80% of each years recruitment will become transients and not have the fortune to establish a successful range. An average of course. So are these transients Decoys????? yes, they are a product of natural selection, but a very predictable one. Cheers

You would have to demonstrate that random selection and survival of the fittest are NOT in play with the 80% / 20% in order for the decoy theory to be valid.

Otherwise, he is just using the term decoy to describe random selection & survival of the fittest (which is fine if that's what he wants to do, but it doesn't take 50 more posts to get that point across to him - or does it?

Joe, see Pyromaniacs post above. Perhabs Decoy is a bad term again to use in this case. Maybe "assigned" to be failures or prey to allow survival of more fit members of the clutch would be a better description. FR brought up ants in one of his posts thats a great example of what my question was about. Ants are preassigned their roles in their colonies. They are either workers, soldiers, breeders. They do not chose their roles, or change their roles at later dates. They just perform what they have been pre determined to do for their colonies. I guess I was trying to extrapolate that to clutches of reptiles. Are some of those babies in those mega clutches pre-determined to be prey or decoys to give the ones most likely to survive the best chance possible? According to Pyros post, there are some insects, and even amphibians that appear to do this. Even some suggestion certain montane species of snakes do this. Kinda of like certain boids that eat their slugs. These slugs serve a function to give the previously non feeding female a source of nutrients as quickly as possible after laying her clutch.

>>Maybe "assigned" to be failures or prey to allow survival of more fit members of the clutch would be a better description.

I think you are just trying redefine something that is generally accepted (survival of the fittest)

>>>FR brought up ants in one of his posts thats a great example of what my question was about. Ants are preassigned their roles in their colonies. They are either workers, soldiers, breeders. They do not chose their roles, or change their roles at later dates. They just perform what they have been pre determined to do for their colonies.

If you can demonstrate that certain members of a clutch smell or taste different and that predators know or can tell the difference then your decoy theory might hold water.

>>>>I guess I was trying to extrapolate that to clutches of reptiles. Are some of those babies in those mega clutches pre-determined to be prey or decoys to give the ones most likely to survive the best chance possible? According to Pyros post, there are some insects, and even amphibians that appear to do this.

Explain why this is not simply survival of the fittest. The younger / smaller / weaker get eaten. Yes? Or do they taste smell different and the predators ALWAYS select the ones that taste the same (no random selection).

>>>Even some suggestion certain montane species of snakes do this. Kinda of like certain boids that eat their slugs.

So now we have decoy slugs? Nonsense.

>>>>These slugs serve a function to give the previously non feeding female a source of nutrients as quickly as possible after laying her clutch.

Explain what this has to do with your decoy theory? More nonsense.

A decoy's the guy I shove in front of me to catch the bullet

I don't think there's any delibiration to it; the most ideal reproductive strategy woudl be to produce animals that survive, since you wouldn't invest time/energy into producing something that won't carry on your genes...that just doesn't make any sense, there's no genetic payoff for producing an offspring that fails to breed is there? Logically it'd be better to produce 20 hatchlings that could all survive and reproduce than producing 10 class A hatchlings and 10 decoy hatchlings....
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We wouldn't have 6 and a half billion people if you had to be beautiful to get laid.
6.6 African House snakes
3.2 reticulated pythons
.1 corn snake
4.2 Florida Kings
1.2 speckled kings
1.2 ball pythons
0.0.1 Argentine boa

I'm trying to help Kevin see this, but after our last go round, I'm just wasting time and practicing my typing lol

I do see your views as to why the decoy theory doesnt hold up in your opinion. Thats all I was asking for people to provide. Some like Terry Dunham, Pyromaniac, MarkG, and even FR provided their opinions, whether for or against, without insinuating anything or arguing over it. You do not agree with the notion. Thats fine. Just state your reasons why, and move on. But why turn it personal or insinuate I am a bad herper cause you disagree with the idea? Maybe I am just being too argumentative over a post I never intended to be argued about?? Sometimes I feel an argument would break out if I asked this forum "Whats your favorite color and why?" LOL!!

Actually Kevin, the insinuation is that we can't communicate.

Your reply further proves my point. I made a point down below over ten times, and you ignored it every time and to the end, theus the statement by me "I'm wasting my time" because you do not understand.

Now, in order to prove to me that you can actually read and comprehend english, please acknowledge this post.

Post acknowledged. I am sending you a PM.

>>Post acknowledged. I am sending you a PM.

Thank you