Reptile & Amphibian Forums

The thread burned itself out(as all threads should) but Cane05 brought up a very very good point. So I thought I will attempt to continue that direction of the thread.

Heres the interesting parf of Cane05 post.

Posted by: Canes05 at Sun Mar 19 09:58:45 2006 [ Report Abuse ] [ Email Message ]

I have one more generalized statement that I would like to throw out there: In the animal kingdom you have animals with distinct home ranges (resident animals) and animals that are constantly on the move (transient animals). If animals where unable to survive in a different location (but similar habitat), the whole concept of transients falls apart.

I responded with this,

They normally perish by becoming food for predators, as they roam often and expose themselves to danger. Cheers

I would like to explore this idea. In my opinion, the vast majority of snakes that are being relocated are indeed transient individuals. In many cases, individuals that have had their normal areas and their normal behaviors disturbed. They are far more apt to be found by people as they do not have secure homes.

I am aware this is a much better(more accurate) statement in the west where snakes rarely use human homes as their homes. As an example. In the twenty years I have lived on my property, we have seen many hundreds of snakes on it. Only one was in the house, and very few, actually next to the house(crawling around the edges) the vast majority were away from the house.

In the east, I am sure ratsnakes attempt to live in houses(i wish we had ratsnakes)

Back to the direction of this thread, that is, transient individual snakes. As I stated, its my belief and a common belief amoung biologist, that transient individuals are not long for this world.

In my field work, I make this observation. About 80% of the memebers of the population are transient and 20% are stable. Of course this varies from species to species and year to year. Example after drought years, theres a much much higher percentage of stable individuals. The transient individuals suffer the most loss.

Of real importance is, the stable individuals are the breeder stock of a species. That is, they account for the vast majority of the successful recruitment. This also varies, but what is important is, the horrible years or periods, these stable colonies/individuals/pairs, are the seed stock that keeps the whole population in exsistance.

What I am trying to express is, there are relative importance of stable individuals vs. transient individuals. Thoughts anyone? cheers

P.S. Also consider, there is no one way or the other, theres no right or wrong, there is only averages and tendencies.

FR
Could one conclude from this that road collecting does not impact greatly the stable populations (of kingsnakes)?

Yea, I think you can say that(in theory) Over the decades I have looked at areas that were heavily road hunted. The populations were not effected what so ever. On the otherhand, habitat destruction does indeed effect populations. Eliminating some species, and providing homes for other species.

Also, in my work with resident populations, a high percentage of females are gravid most years. Yet, finding the same species gravid, ON the road, is very very very rare.

ALso finding large adults on roads is very very rare, its happens but not often. For instance, at the rattlesnake breeding sites, the average diamondback is four to five feet. Yet, its very rare here to find a diamondback over three feet on the road. Most are 24 to 30 inch yearling males or babies.

Take pyros for instance, I can find gravid females very commonly, in fact, most are gravid(right time of year) These individuals are congregated in certain areas. To find a gravid pyro just crawling around, is very rare. So even off the road, the stable individuals do not crawl on the surface or in the open very often.

But, a road is not always a road. There are roads that transect snake pathways, that is, that cut between summer and winter ranges. So at times, these roads can indeed impact the stable populations.

So a single answer is not to be found, but surely its better to "take" an individual off a road. Then it is to "take" an individual from a stable setting. Cheers

...come to think about it. i have caught or seen about 10-12 snakes in the last two weeks of road cruising and scouting for a chain king. all were juvies and young adults. d.o.r.s that i have looked at were the same. i never thought about that and it makes your point. i caught a young male garter crossing a road at 4:00 pm e.t. today he looked to be in great health. i put him in the woods off the road in the direction he was going. i do see larger d.o.r.s after a heavy shower. mostly cotton mouths and banded water snakes.good point!
jason wilson

Great info as always, thanks.

Looking at notes, I see that by far most of the snakes I've found on roads were young animals. It makes sense.

Regarding Winter and Summer ranges -
In So Cal we have some hilly coastal terrain near me. We occasionally find Cal kings and gophersnakes there. In mid/late Spring when I've found some snakes crawling out during the day, they were always aimed going down the hill, or sideways but still going down.

I've always wondered if the snakes Winter higher on the hillsides and come down some when the ground gets warmer.

I took some temp readings at burrows in Winter on a clear day about 75deg F. The burrows about midway up the hill were warmer at the entrance than the burrows at the base of the hill. Base of hill were often in the 55-60 range a few inches down into the hole. Burrows up the hillside were up to 15 deg warmer, and those near rock got up near 90. These were on South or S-W facing hills. The tops of the hills had burrows but less cover from wind.

Does it makes sense that these snakes here would want to stay higher on the hillsides (but not too high) over the Winter?

Problem is as always, I don't know what the snakes want. Well, maybe the most advantageous range of temps for themselves. What is that in Winter?

Interesting discussion Frank. We tend to see few really large snakes alive or dead on roads except during Sept when as you mentioned snakes may be making seasonal movements that happen to traverse a certain road. In general we tend to see fewer large snakes in the proximity of roads. Maybe those snakes that have established home ranges within convenient crawling distance of roads tend have their life expectencies shortened on average before they can grow to truly large sizes. On the other hand the vast majority of really big snakes we find are well removed from roads that receive significant traffic.

I think you made good points on the perils of relocating snakes. There are a number of studies with various species that back this up. I once collected a particularly handsome milk snake that failed to thrive in captivity. After several weeks I decided the best thing to do was to release the snake back to the field. We actually made the three hour trip back to where the snake was originally found to release it since that was in our minds the only option. Phil

you get past the basics. But for the purposes of this thread, its best to stay within certain parameters.

Yes, the studies indicate that its rare for any individual to survive if moved over a certain distance. For instance, a kilometer(5/8's of a mile). That is the results of actual keeping track.

Once everyone understands that there is a problem with moving snakes, then the next step is to investigate why its a problem.

Sure many snakes and certain species at certain times move greater distances then a kilometer. But they are moving from a specific location, that is supporting its life, to another specific location, that is supporting another part of its life.

The main problem is education, that is, the knowledge to recognize, what a snake is doing. Is it a transient or a resident? and how do you know? Would you treat a resident the same as a transient individual? Of course not, these types of things are the next step.

Also, some folks here keep bringing up adaption. They misinterpit adaption as something an individual can do on the fly, that is, an individual can adapt within a short period of its own life. How wrong is that?

They do adapt, ever so slightly, but not in an individuals lifetime, but over many generations. For instance, Urban poplations, must adapt to live in farms, and vacant lots, etc. These individuals must change their behavior to meet the new conditions. They must not travel very often in the day, or on the surface. To many new predators(humans) Or roadside populations, must learn to not cross traveled roads.

This learning or adaption is not done with a single individual changing its behavior(LeMarkian evolution) But thru selection, the individuals that commonly crossed roads, were eliminated, and the individuals thats personal behavior stopped them from crossing roads(darwin) pasted their behavior on to the population, genetically. Yes, a farm building Blackrat, has different behavior, then a deep woods blackrat. Same for kingsnakes, etc.

But the interesting part is. This adaption is not really an adaption. This ability is a natural design to allow snake species to establish populations in a varity of different habitats. The snakes with a wide range of habitats are considered, generalist. Snakes with a narrower range, specialist.

What is sad is, this is only basic biology. And it appears its not understood by many here. For you teachers out there, a mass failure of the education system.

Also advanced discussion of relocation studies should include, method of study. In my opinion, the use of transmitters and pit tags, induces transient behavior. So does radio tagging actually contribute to the lack of successful relocation. Of course it does, but the question is, how much.

The problem with reptiles is and has always been, lack of recognition of behavior. The public and biologist refuse to recognize that snakes have behaviors. Muchless the extent of those behaviors. Of course some country folks that are continously exposed to snakes recognize that snakes have behaviors. You know, on the dark of the moon in august/sept, do not walk around in the woods as all the rattlesnakes are in shed and blind and will bite first and not rattle. Or after the first rain in spring, the ratsnakes will gather over thar in that sunny meadow and bask(Git the gun mabel). etc etc. Of course theres the old, in early summer, the milksnakes head to the barn to suck the tits of the cows. Ok, it has nothing to do with the mice that are so abundant in the barns at that time. Cheers

Yeah, I think the habitat specialist would be especially vulnerable to translocating. Two studies I recall off hand involved timbers and eastern hogs. Seemed they faired very poorly when relocated. If I remember correctly the timbers involved were snakes that were ID'd by scale clippings that were coming into contact with folks as land was cleared for summer homes in mountainous regions in the northeast. The snakes that were moved often were later found DOR or back at the summer cottages roaming around instead of establishing new home ranges.

I guess one could be led to believe that a habitat generalist may fare better but no doubt, the learning curve would be great still and untimely death likely. The racer comes to mind with its high risk/high reward life style. Feeding opportunities may be great but the cost is a higher metabolic rate to drive the machine and greater exposure to potential predators.

Its interesting to me how many folks here in Ky truly believe that they have been attacked by racers while walking through a field. When taken by surprise these agile snakes usually make a bee line to the closest known refuge in their home range which may well be on the other side of the person in question. I guess the perception to them is the snake is making an aggressive overture when in reality it is simply relying upon its speed to get to a safe place in the shortest time and distance. All of this digresses from the subject a little, but it does illustrate how even a habitat generalist such as the racer is finely tuned in to its home range and knows every nook and cranny. In the game of survival seconds and inches are often the difference between life and death.

It does seem that those snakes with truly large home ranges such as pines, Indigo's and those types of species are having a tough go of it due to habitat fragmentation.

Cheers, Phil

That was a very good response to the transient/resident topic I threw out there. I agree that residents may be longer lived than transients, in general. I can, however, think of a few examples where transients do as well, if not better, than resident animals...unfortunately none of them are snakes! haha. In every example of a successful transient animal that I could think of, the animal was an apex or top predator in its ecosystem. They had no predators to fear (other than man, who is THE apex predator), and therefore, are quite successful in their transient lifestyle. The first animal that comes to mind is transient populations of killer whales (sorry for the non-herp reference, but marine biology is my thing).

I think, and it's only a theory that the transients main function is to expand range and to fill new vacancies in established homes.
Regarding the roads I believe after hunting a certain local road for many years that I've found a few "snake corridors" in the form of gorges that cross the road.

I've been kicking around an idea about how roads may affect certain snake populations. Similar to the idea that a road can hurt a population if it's between a snake and its winter den. Due to environmental conditions, or other aspect of a snakes behavior, a majority of animals from a certain population may gradually or suddenly migrate from one area to another. I'll give flooding and drought as an example, as these conditions can last years in some areas. During prolonged wet conditions, snake populations (especially those of ground dwelling/fossorial species) may seek higher/drier ground and move from the lowlands to the highlands (relatively speaking). Semi-arboreal species (like ratsnakes) may just take to the trees instead. Similarly, in dry conditions, snake populations may move into the wetter lowlands.

Let's say you have a major highway, and on one side is the majority of your lowland habitat, and on the other side is the majority of your highland habitat, and this highway is so busy that not even 1% of snakes attempting to cross survive. Species that followed this sort of migratory pattern may have their numbers of transient individuals drop severely over time, while the core, nontransient population may remain relatively unaffected. I'd think even the non-transient animals would eventually move if the environmental conditions became too unfavorable. Just a thought...

A case I've hear of where snake populations made a sudden migrations was during the 70s when a hurricane passed through southern Florida. An old collector I know drove out on to Alligator Alley, which goes through miles and miles of swamp, and found hundreds or thousands of snakes of many species on the road, as it was the highest point in the immediate area. Most were dead on the road. The collector told me that this road was not nearly as productive after the storm had hit.

Yep, I travel a few corridors during key wet periods here in south Texas just to get a sampling of what lies out of reach in the fields. I know that in certain times of the year it is a veritable slaughterhouse on the road, while 95% of the time there are little or no snakes crossing the road. The stable populations stay where the food and shelter are plenty and the young disperse only to become pancakes. I have seen a few gravid hognose and a coral smashed with eggs scattered, but if I remember correctly it was after heavy rains flooded the fields. 99% of the dor's I find are younger male snakes. But I have had a W. coachwhip come up to me and stare me down, Phil! I think it was very curious and HAD to see what this new thing was. It did beat a hasty path after the challenge was accepted. I lost! But it did stick it's head back up for a second look from 30 feet away in high grass! It didn't chase me but it did come to see what th' #@^* I was! I find most of my corridors in low depressions on the road or close to a bridge type structure that will hold water.
Todd Hughes