# Husbandry Improvements - Stress



## kyle1745 (Feb 15, 2004)

Starting this discussion on reducing the stress of our animals in various aspects of their care.


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## Ed (Sep 19, 2004)

The first thing is to define what we are referring to as stress 
(there are some useful definitions in Health and Welfare of Captive Reptiles (editors, Warwick, Murphy, Frye, 1989 (for hard cover, 2002 for paperback version). 

There are positive and negative types of stress and in a different thread (multispecies enclosures) I refered to stress as anything that disrupts the homeostasis of the animal... 

Ed


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## kyle1745 (Feb 15, 2004)

Im not sure I can list different types of stress, but I can list ideas on things I think can contribute to stress that some may sometimes be over looked.

1. Shipping

2. too many animals in a small space

3. adult stress due to same sex animals in the same tank

4. from frogs in adjacent tanks, Ive seen some of my tricolors just about freak out over frogs next to them. Most of my tanks are painted on one side so they can not see through but I had a case where I had to put some together without painting them...

5. temperature swings

6. too much food or too little food


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## Ed (Sep 19, 2004)

Hi Kyle,

Those are stressors(things that cause stress). Stress itself is a physiological and/or behavioral response to stressors (that to can be measured via circulating hormones). 
Stress caused by negative stressors can cause significant physiological changes up to and including stress (which in newly imported animals is called maladaption syndrome). 
Levels of negative stressors that do not lead to rapid death increase corticosteroid levels in the blood stream (in reptiles this can last for two weeks or more), depress testosterone levels, and/or lead to immunosuppression. 

Ed


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## kyle1745 (Feb 15, 2004)

Ed,

Yes I knew they were causes, but could you list the different classifications of stress? or are we talking a ton of information here? Any related information online that you know of?


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## bbrock (May 20, 2004)

You forgot an important stressors. Big ugly apes poking thier noses into enclosure all the time. I actually think this is a serious problem for some new hobbyists.

I've discussed this with Ed before but it has always bothered me to measure stress purely in physioligical terms because it seems to me there could be stressors which disrupt behavioral processes but do not elicit a chronic physiological response. So I would also include things that disrupt an animals ability to perform normal ecological functions or life history process as stressors.


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## Ed (Sep 19, 2004)

snip "I've discussed this with Ed before but it has always bothered me to measure stress purely in physioligical terms because it seems to me there could be stressors which disrupt behavioral processes but do not elicit a chronic physiological response"endsnip

Yup, we have been there;
but in general, the physiological response depends on the magnitude of the stress (or response to the stressor). (I am sticking to negative stressors here as in general we do not understand (as far as I can determine) how positive stressors cause physiological responses.) 
I have been digging into this further since our last discussion and even what appear to be relatively minor stressors can have longer range effects.. (I'm going to have to get copies of the next two). 
Some interesting abstracts 
Tyrrell, C. L. and A. Cree. 1998. Relationships between corticosterone concentration and season, time of day and confinement in a wild reptile (tuatara, Sphenodon punctatus). Gen Comp Endocrinol. 110 (2):97-108

Denver, R. J. 1997. Environmental stress as a developmental cue: corticotropin-releasing hormone is a proximate mediator of adaptive phenotypic plasticity in amphibian metamorphosis. Hormones and Behavior. 31 169-179. 

Gregory, L.F., T.S. Gross, A.B. Bolten, K.A. Bjorndal and L.J.Jr. Guillette. 1996. Plasma corticosterone concentrations associated with acute captivity stress in wild loggerhead sea turtles (Caretta caretta). General and Comparative Physiology. 104 312-320. loggerhead 


The problem is that corticosterone increases are also negatively correlated to growth so even low stress levels can have long term impacts. Keep in mind that if the stress is constant and not excessive the animal will adapt to the stressor (repeating is constant) and the circulating levels of corticosterone will drop back to normal. 


Ed


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## kyle1745 (Feb 15, 2004)

Great point Brent I know some of the best advise I got when I was starting is to just let them be... Boy was it tough to not check them out all the time.

I think this is one of the reasons my frogs seem to be doing so much better that they are now in the basement. Most of the time there is no one around down there.


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## pl259 (Feb 27, 2006)

When I was raising Iguanas I used acrylic panels covered with solar film for exactly that reason and to help keep in some heat. The film was 50% silvered, actually bronze colored, and acted like a two way mirror when the cage lights were on. I still have some of that film and was actually considering using it on my racks in a window shade like fashion.

The jury is still out on that idea  

EricG.NH


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## kyle1745 (Feb 15, 2004)

Also something that maybe tough or impossible to measure is the stress from other tank mates. I often wonder if some species do not care to be that close all of the time.


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## Ed (Sep 19, 2004)

snip "When I was raising Iguanas I used acrylic panels covered with solar film for exactly that reason and to help keep in some heat. The film was 50% silvered, actually bronze colored, and acted like a two way mirror when the cage lights were on. I still have some of that film and was actually considering using it on my racks in a window shade like fashion. "endsnip

When dealing with a visually territorial species providing them with a reflecting surface may cause significant stress in the animal. 

There is a phenomena called the dear enemy phenomena. In a number of different species the animals involved react differently to strange animals in or close to thier territories than they do to the same animal in the adjacent territory. I strongly suspect that this does come into play in the enclosures that are kept near one another with the frogs calling. (see Polly Frostman; Peter T. Sherman; 2004; Behavioral response to familiar and unfamiliar neighbors in a territorial cichlid, Neolamprologus pulcher; Ichthyological Research 51(3): 1341-8998 as well as associated bibliography for a good description). This reduces the stress and allows for better resource allocation in the animals in the adjacent territories (in this case the tank). 


Ed


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## pl259 (Feb 27, 2006)

> When dealing with a visually territorial species providing them with a reflecting surface may cause significant stress in the animal.


Agreed. Keeping these kinds of animals in a mirrored box would not be a good idea. In practice, however, in my Ig setup, the film was only near the top of the enclosure in their basking area. The film did not lay perfectly flat and reflected a very distorted image. Further, the bronze tint did not reflect the true colors. They basically ignored it and gave no behavioral responses to any reflections. No head bobbing, ect. But, the view from outside in, was very clear as the transmitted light from the inside, passed right through virtually unchanged. 

A pull down screen, as I'm considering for the front of my racks, would be even more distorted. It's mostly for temperature control reasons. While it would also block the view of big moving human heads, I'm also in favor of conditioning the frogs to get used to humans, provided it doesn't stress them out.

Are these white papers that you cite generally available?

EricG.NH


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## Ed (Sep 19, 2004)

snip "I'm also in favor of conditioning the frogs to get used to humans, provided it doesn't stress them out."endsnip

This is a relatively easily accomplished item (somewhat species dependent) as long as the frogs have access to shelters where they feel they can safely retreat if they feel threatened (and you don't go digging them out of those shelters just to see the frogs). 
The availability of shelter is the important part here.. 

One of things people should remember that the minimizing disturbances to the enclosure (restrain the urge to constantly replant, move/redecorate, add more plants to the tank) as much as possible. 

The availablilty of a lot of the papers I cite is dependent on your local university but acess to most of them can be purchased on line if the university doesn't have them. It may also be possible to get the journal through a interlibrary loan. 

I was first introduced to the idea of the dear enemy phenomena by Dr. Judy Stamps at a SSAR conference about 12 years ago.. 


Ed


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## npaull (May 8, 2005)

We should also keep in mind here what the goal is. If we are trying to recreate natural situations, then the elimination of all stress is a ridiculous aim - living in the wild is as stressful as hell.

A certain level of stress is natural - do we want to reduce it? Eliminate it? Wild frogs deal with territorial encroachment, competition, fighting with conspecifics, etc. all the time. May it in fact be that captivity is LESS stressful than the native state for many of these frogs? I'm not sure that it is (and it certainly varies with the other criteria discussed in similar threads; in some situations there is undoubtedly much more stress, but in a giant, predator-free vivarium...?) but it is something to think about.

Just some thoughts.


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## Ed (Sep 19, 2004)

snip "We should also keep in mind here what the goal is. If we are trying to recreate natural situations, then the elimination of all stress is a ridiculous aim - living in the wild is as stressful as hell."endsnip

It is stressful but often the animal can escape from or in some other way mitigate the stress. This may not be available to animals in captivity which is where you need to consider the level of stress applied to the animal. 

snip " Wild frogs deal with territorial encroachment, competition, fighting with conspecifics, etc. all the time."endsnip

Which in captivity we tend to eliminate as soon as we notice it (or it resolves itself in other ways). With many animals, the territorial boundries are not the section that is defended the heaviest, instead the borders tend to be somewhat flexible and overlap with the core areas being more heavily defended (and this does not count animals that have a range that consists of several overlapping border areas called floaters in some of the literature). This is because in the wild, the animal cannot be everywhere in the territory or defend all borders at the same time and the territory needs to contain everything the animal "needs" (calling sites, courting sites, feeding sites, ovipositioning sites, tadpole depositing sites etc). I think the reason that we are able to breed the animals in such small enclosures is because we supply the "needs" in a small area allowing for a very small core territory.. (Now this does not mean nor should it be taken to mean that everything is fine as long as we supply all of the needs in a small enclosure as a larger enclosure may be more optimal for other reasons.)

snip "May it in fact be that captivity is LESS stressful than the native state for many of these frogs? I'm not sure that it is (and it certainly varies with the other criteria discussed in similar threads; in some situations there is undoubtedly much more stress, but in a giant, predator-free vivarium...?) but it is something to think about. "endsnip

Maybe....but probably not... It depends on a lot of things.. check out Health and Welfare of Captive Reptiles as this topic is well discussed with respect to reptiles... 

Ed


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