UVB Light - its pros/ cons

[Stu&Shaz]

Answering the questions about light and the canopy, good timing really I have a book coming out entitled lighting for understory species. There is a whole section on dendros in the book. I will quickly explain my findings from the research papers available.if we take all light as 100%, after all absorption from atmosphere and clouds and canopy, the average % of total light making it's way down through emergent, into the canopy and then into the understory via leaf scatter would be about 4-6%. Any shiney or wet surfaces would reflect light and Uv back up into the ecosystem, this could mean that this energy is reusable to animals with adapted skin for absorbing low levels. This is a surprising amount, now we all know that different frogs come from different elevations, the trick is to match your captive environment to the wild. So a species from a higher altitude is provided with more mws2. Dendros are as we all know able to see UV. This is a godsend for them and us! It simply means that we can use higher powered T5 lamps over a small area in the enclosure, decorate the enclosure accordingly so that the frogs can photoregualte from say 40-50cms at the furthest point to 15-20cms at a basking platform, the frogs are the experts!!! They are able to photoregualte very well, they will move in the enclosure to get what they need, when they need it. I would be far happier providing high levels of UV over two thirds of the enclosure even for 6 hours a day and letting the frogs regulate themselves than using a low powered lamp over a wider area for longer! Cool and shade is just as important to the chemical changes in the body as heat, light and UV. Ideally we should all be providing light and shade. We keep bumblebee toads in the office here, they come from a high altitude and are very diurnal, so no supprise that they sit 10cms under a very powerful lamp for sessions of about 10 mins at a time at least 3 or 4 times a day! This is providing around 40-60mws2 with that lamp at that distance. I hope this is helpful!, John.

Just a thanks Jon for everything,ha ha do how you find the time mate!! Great to see you here,and to have your wisdom on this subject,which as you know i believe is so important to our frogs.It never ceases to amaze me that everytime you write something i seem to learn something new,i had no idea that our darts could see UVB!!!!!
best
Stu

[Lady Bullseye]

Thanks very much for the post John!
Maybe the UV has a connection to some species I read about being hard to breed.

[Philsuma]

anyone ever see a Dart Frog 'Bask" in UV light ?

I have...a subadult Basti pumilio. I'm 100% sure of it. The temp tank was on very low 'fish tank" lighting and when I put a spare halogen flood lamp on it - it was a 20 gallon vert with decent plantings and wood....the frog absolutely came out and into the light and stayed there. 100% due to the bright light. I'm positive, as I watched it all occur a couple times.

Some theories:

1. The frog was vitamin deficient and was seeking to reclaim some 'A' or other items.

2. The change in lighting from ultra dim to bright excited it...just like we get on a sunny day. Ever see wildlife explode after a dark day / rainstorm and all of a sudden the sun comes out really bright. Also an animal 'celebration'.

3. Just plain aberrant behaviour.....don't mean nuttin'.

4. You tell me.....

[ChrisK]

If the light was thru glass, it definitely wasn't the UV.

[Philsuma]

It was through glass. Maybe the frog wasn't gettin' the benefits of the UV wavelengths...but it certainly WANTED to.

[Stu&Shaz]

If the light was thru glass, it definitely wasn't the UV.

Depends on the type of glass i guess Chris,but unless its optiwhite/yours starfire (ie low iron)your probably on the money...it could be just warmth it could be they do want uvb.
Phil our auratus regularly do this early morning sun catches their viv,they stand up front,follow the chink of sunlight. Phil really recently someone was telling me about auratus doing this in the wild in CR catching some early morning rays. I haven't seen basking under any uvb set ups yet,but hell its there if they want it. I s'pose I'll have to get some pums then :lol: to see what they make of it all.
See how it happens you get the best lights,then ya have to get some blummin obligates to live under them, we are going to be poor but happy froggers for along time methinks.

tough huh
Stu

[heyduke]

I realize Ed doesn't post much over here but there is a pretty good discussion over there about the benefits and behaviors of dart frogs and UVB.

For technical answers Todd from light your reptiles has measured the UVB penetration through screened ventilation and his findings were pretty surprising and encouraging as how to add this to our care taking.

I would link stuff but Phil doesn't like linking to other forums. He can if he likes.


Sean

[Philsuma]

..and they don't like the linking of stuff to Dart Den. Try it sometime and see what happens...lol.

Todd's info and opinions are the exact same and documented here. It's all here as well. I like Ed, I really do, but sometimes his message comes across as 'all Charlie Brown Teacher-like"......whawmp, whawmp, whawmp...UV...whamp, whamp, partitioned nutrients....whawmp, whawmp. He SHOULD (and I THINK he will) tell you that he is not an expert. I haven't met a single Dart Frog husbandry expert on any forums yet.

We do just fine with our discussions here.

[Arcadiajohn]

Hi all, this is as our findings From our in-house research. some UVA can get through some glass and this would in theory activate the tetrachromacy or varient of. Again in theory the frog would be able to see these power gradients and adjust it's body to make use of the light, but let's look on the other hand. we know that reptiles and amphibians of all species are effected by the LUX or level of light. They do tend to seek out high quantities of light at differing times, these higher amounts of light can spur on an increased colouraton, feeding spikes and a whole host of other small changes. Most people that move to HO T5 from Arcadia give feedback of higher, stronger colours in the animals, this is partly due to a proper activation of the D3 cycle through UVB and the increased LUX from the lamps. Now for us it is always to do with the wild animal. Our quote is "All the sectrets of great captive care are hidden in the wild animal". To get an idea of why they may behave like this and shake our preconceptions we can look at forest life. Look at the local, google up the average UV index and hours of sunlight we can then work out a possible exposure level. Dendros like most forest animals use "Leaf scatter" illumination to find columns of light and energy. Having the gift of 100 million colours including the far blues into UV they can if they require move a part of the body into these sun columns as they travel through the canopy in millions of pinpricks. We can use the elivation above sea level and their own preferd living position in the forest to work out a usual index. If say the index at the emergent is 6-8 index the power decreases as as the light travels through into the canopy and understory. Now reflected sunlight reflecting off of broad and waxy leaves is almost just as powerful and direct sunlight as the top but decreases in power the more times that this column is reflected. So if the index is 6-8 at the emergent the usual index on the forest floor would be 2-4. An index of 2-4 is re-created with a 6% D3 lamp in T8 at around 12-15" from the lamp and from T5 about 18-24". But if the frog lives in the mountains of in the upper canopy the average exposure would be greater asd the light hasnt travelled so far. So the clues are in the wild, we can then use this data to generate a workable photogradient. we can re-create leafscatter by lighting only a portion of the enslosure and planting accordingly. Then let the real experts, the frogs decide when and where they want to expose and or full on bask. I think that you maybe shocked as to how much exposure that they allow. Our Bumblebee walking toads for example will bask in an index of 4-6 for at least 2 hours a day. This is a mountain species and so the Index would be higher than a Under canopy animal. keep the obsevations coming in, this is how we learn!!!! from each others animals. john.

[Stu&Shaz]

..and they don't like the linking of stuff to Dart Den. Try it sometime and see what happens...lol.

Todd's info and opinions are the exact same and documented here. It's all here as well. I like Ed, I really do, but sometimes his message comes across as 'all Charlie Brown Teacher-like"......whawmp, whawmp, whawmp...UV...whamp, whamp, partitioned nutrients....whawmp, whawmp. He SHOULD (and I THINK he will) tell you that he is not an expert. I haven't met a single Dart Frog husbandry expert on any forums yet.

We do just fine with our discussions here.

Especially with post's like above,thanks John. Fascinating !!!
regards

Stu

[RichFrye]

... "All the sectrets of great captive care are hidden in the wild animal". .. john.

And the key to understanding the wild animal is to spend the most time and situations possible in-situ.
I've read statements founded on pictures in books such as ' very high density in pums is natural , and therefore high density in vivs is acceptable.'
What the statement/theory does not take into effect is high density in the wild may be the norm for about one hour , in one day, in the correct situation to take a nice picture. Very high density is not the norm , as when breeding for that period is done, so is the co-habitation...
Remeber, for every one frog you happen upon out in the open, there are most likely a couple dozen or more hiding/living in the dark, not rubbing elbows.

The following pictures are all dart frog habitat and all frogs were found (using high lumen flash lights) in the darkest areas of the pictures. Over years of documentation. In many different months of the year and times of the day.
What was found in most all cases (95%+) was that the darts all tended to find comfort in the darkest areas and were only found in brighter areas while moving, not calling or laying . A male would go only as high on structure in the jungle so as to see a potential mate (or predator) approaching, while staying out of direct light. And escape always was toward dark areas.










What I have found in the wild essentially coincides greatly with much known hunting and fishing facts.
Frogs come out to hunt and breed with the rain, moon phases, barometric pressure, etc. They are much harder to find when the sun is brightest...even though the temps, humidity and factors which keep them alive and well may be well within the acceptable range, they don't crave sunlight.



I've found the most active breeding and hunting to be in the rainy season during light rains ( frogs and most animals don't like torrential storms...) , early in the morning, with total and complete cloud cover, when the barometer was falling.




Why does it seem a benefit and at times craving to absorb some UV or light in general? Quite possibly a lack in diet from what the in-situ darts naturally get, and quite possibly a tend to thermoregulate a bit. Or a combo.
Both of which can greatly be controlled by things other than artificial UV use in vivs.
Quite possibly there are other factors, but my main yardstick in dart husbandry is as such
#1 long lived frogs
#2 continual and regular good health
#3 good and natural breeding

In that order.


Rich

[Philsuma]

Excellent counter-response Rich.

The only thing I would add, is that there is almost always a middle ground to be had in most everything, including husbandry of small 'exotic' animals.

I would recommend - all things being equal, a LARGE size vivarium with a choice of many different gradients. Humidity - layers of leaf litter and strategically placed misters allowing for a chance to occupy a very wet area of the viv, or a medium area, or even a dry area. Same with ventilation (a little harder to replicate) and definitely the same with light. An area where they can seek out some higher intensity light for a few minutes /hour...and then plenty of retreats or sections where there is nothing but shade and soft light. Let them choose.

THIS is why the '10 gallon' crowd is a....fail.

[Rusty_Shackleford]

Other than the expense of adding UV lighting I don't think there are any cons. Are frogs in the wild exposed to UV light? Absolutely. What we don't know is the exact amount they are exposed to. IMO some UV light is probably beneficial to an extent. But we must keep in mind that most of the frogs we keep are found in around leaf litter on the forest floor where UV levels are the lowest. So if you take the route to add UV lighting, keep this mind. I don't think it would be beneficial to have a 10.0 UV bulb over the tank for 12 hours a day. That would probably be very unnatural to the frogs. But a 5.0 or 2.0 UV bulb for a few hours a day probably wouldn't hurt and could quite possibly help with the overall health of the animals. After all we don't know how much frogs "bask" in UV rays, nor do we really know if the Vlt. D3 they receive via supplementation is enough or too much for them.

[RichFrye]

Other than the expense of adding UV lighting I don't think there are any cons...

Strictly playing Devil's advocate, and understanding the rest of your post Jon , and agreeing with most of it...there are plenty of cons to all things living and many dead to over-exposure to UV radiation.

[Rusty_Shackleford]

Other than the expense of adding UV lighting I don't think there are any cons...

Strictly playing Devil's advocate, and understanding the rest of your post Jon , and agreeing with most of it...there are plenty of cons to all things living and many dead to over-exposure to UV radiation.

Rich I understand what you're saying and I agree completely. That is why I said our frogs would be better served with a 2.0 or at most a 5.0 UV bulb, as opposed to a 10.0 UV bulb which would be used for desert dwelling reptiles such as a bearded dragon. In additon to that limiting the amount of time the UV bulbs are on, say from 10am till 2pm, which is the highest level of UV exposure in the wild. NOT letting the UV bulbs run for 12hours a day like we do with our regular viv lights. That way the frogs do have a choice, the can, if they need to, expose themselves to those UV rays for four hours a day and they also have the choice to bury themselves in the leaf litter, or under plants if need be.

[RichFrye]

Other than the expense of adding UV lighting I don't think there are any cons...

Strictly playing Devil's advocate, and understanding the rest of your post Jon , and agreeing with most of it...there are plenty of cons to all things living and many dead to over-exposure to UV radiation.

Rich I understand what you're saying and I agree completely. That is why I said our frogs would be better served with a 2.0 or at most a 5.0 UV bulb, as opposed to a 10.0 UV bulb which would be used for desert dwelling reptiles such as a bearded dragon. In additon to that limiting the amount of time the UV bulbs are on, say from 10am till 2pm, which is the highest level of UV exposure in the wild. NOT letting the UV bulbs run for 12hours a day like we do with our regular viv lights. That way the frogs do have a choice, the can, if they need to, expose themselves to those UV rays for four hours a day and they also have the choice to bury themselves in the leaf litter, or under plants if need be.

^Agreed.
As long as the frogs have the option to opt out, I don't see too much being effected in a negative way. Only one reason why bigger, all things equal , is better.
But, when I read reports of UV being used in 'scientific' testing on tads and those tads "only receiving superficial burns..." I wonder how many people dealing with skin cancer thought their sunburns were superficial.

[Rusty_Shackleford]

Absolutely Rich. It's better to err on the side of caution when using new and unproven techinques such as this. If we start out limiting exposure with low rated UV bulbs and limiting the amount of time the bulbs are on, we can always increase the rating of the bulb or the number of hours they are on if it proves to benefit the frogs. Much like lumping or splitting, you can always lump together later, but you can never split later.

[RichFrye]

I'd also mention as a side-note , but going back to natural situations, most all vivs look nothing like what we see in nature.
Take any pic of natural dart habitat and cut the natural plants down to highest amount of space anyone has from substrate to lighting. That space for me would be about 26" in my tallest viv. How many plants top out at 26" in the wild?
We see tremendous fight for light and a vastly covering canopy. With broms fighting to get to the top and generally only found either in tiny light holes poking through , toppled down from their highest of high perches up top by storms, or in their natural positions at the almost top of the canopy.
What we find in that lower 26" is very low light with very low light plants. Many of those plants either can live with roots totally submerged or on top of the clay substrate. One of the reasons it's so dangerous to climb cliff and hills in-situ is that nothing has a good root base and almost any and all trees and plants are suspect hand or foot holds.

Rock, clay, leaflitter, trees and lightly or top of the substrate rooted vines and plants are what we see. Most all of it in either almost total dark or greatly obscured of natural light , due to the fight for light to reach the upper canopy.
Times I've worn any sunblock or sunscreen while photographing or looking for darts in general...zero. Flash needed or re-orientation of a dart found in most natural settings, pretty much always.

[Arcadiajohn]

Hi all, all of these are very valid and correct assumptions that work within our theory! "All the secrets of great captive care are hidden in the wild animal" that is the statement and works with all of the points. If the wild animal would be able to access an Index of 2-4 (which we assume is the correct level of exposure for most "off the shelf species" even for an hour or two a day then re-creating this over part of the enclosure i.e a photogradient to match your thermogradient as per our advice must therefore be a positive move.

our advice is to as in Stu's set ups to know the true output of your lamps and have researched enough to have a guess at an average wild index and then use these inbuilt lamp limitations to re-create this level of exposure.

The whole 12% for desert animals things really is a nonsense! it is all to do with the height of the viv. A 6% T8 lamp used in a viv of 5 feet high is useless to the animal at is usual living areas if it is a ground dwelling species. Arboreal/self regulating species would be able to use the gift of tetrachromacy to choose their own exposure and move around the viv left and right up and down to obtain the exposure that they are happy with and require at that moment. We are big believers that the animals are the real experts! If we as keepers follow basic lighting rules i.e UV light a third to half of the enclosure starting at the hot end so that your photo matches your photogradient and you allow hiding places and leaf scatter illumination the animal will be fully able to self regulate through the thousands of differing gradients generated in its living space.

Now this theory is dependant on having enclosures that are wide and high enough to generate a gradient and the use of the right lamp for that height and build design and over the right portion of enclosure for the right time.

So we know from our published lamp outputs what lamp does what and what the drop off is like per lamp. Use this info to obtain the exposure that you are happy with. It is widely published that a 15% drop in bone density is viewable via X-ray and that this can be repaired to some small degree after exposure.

One method of exposure used by some major zoos here in the UK is to blast a frog once a week with a high potency M.V lamp. This is called UV boosting. I have seen it in action. I must admit to not being comfortable with the practice even though it does seem effective. I think that it is much less stressful and hot to allow a gentle measured exposure for the right period of time every day via Flouro tubes than to blast it with high heat, high strength light once a week for 20mins.

We know that the D3 cycle is maintained and measured at a constant level in our method and we have seen every subject ever tested move around their enclosures during the day to make use of our method of gradient, we also have seen every species move vertically to obtain a stronger dose up to an index of around 5-6 BY CHOICE!

I think the key to all of this is that we are still all learning, in relative terms we know nothing about captive Dendro and reptile care! We will all look back in even 10 years and think "goodness how things have changed" it is only 15 years ago that we were still using blacklights!!! :-(

So for us its all about wild re-creation. Fit lamps above animals of all kinds and never to the side, light an area that match's your thermogradient typically a third to half the size of an enclosure, use the published output of a lamp "after it has burnt in" to re-create the average wild exposure and use timers to generate this level of exposure for a period of time that you are happy with and above all watch the Frogs, if they openly bask increase the lighting time if the dig in,,,reduce the exposure. We can learn a huge amount from them just by watching.

One rule of thumb that I learnt is that if you can see without artificial light in the country of origin then you have a measurable UV level, if you can see your hand in front of your face the average measured level would be an index around .50 this would be recreated with a 6% T8 lamp at 18-20" from the lamp without reflector and slightly more with.

good luck all!

john

[RichFrye]

Hi John,
thanks for taking the time to go over this for us.

...So we know from our published lamp outputs what lamp does what and what the drop off is like per lamp. Use this info to obtain the exposure that you are happy with. It is widely published that a 15% drop in bone density is viewable via X-ray and that this can be repaired to some small degree after exposure...

I'm not sure how we know what 'we are happy with' yet...or more importantly , our frogs. Is it possible for them to overexpose themselves to UV while possibly craving the heat and not actually the radiation? Or is it possible for them to over radiate as the UV craving sunbathers do?
What species have widely published 15% bone density drops repairable by UV exposure ? I would guess not dart frogs, as many are comprised much of cartilage , with less bone , excepting the much larger species. And real scientific studies on PDFs in general are hard to come by.
I personally only keep PDFs and solely am interested in how UV effects them. I have no interest in other frogs and absolutely not reptiles, as far as my personal husbandry is concerned.

One rule of thumb that I learnt is that if you can see without artificial light in the country of origin then you have a measurable UV level, if you can see your hand in front of your face the average measured level would be an index around .50 this would be recreated with a 6% T8 lamp at 18-20" from the lamp without reflector and slightly more with.

good luck all!

john

I have to admit my lack of all known benefits to PDFs from UV. I have an idea of some benefits, but would be interested in any and all known /proven benefits to the extreme low light frogs , not supplemented by non-UV light , diet or current husbandry given.

I would ask for clarification on measurable UV. I can see during the day without fear of running into a wall or failing to see a cliff I am about to fall off, but can not find darts in their natural settings at any reliable level without high lumen flashlights and flash photography or re-orientation of frogs is an absolute must most all of the time.
I can see my hand in front of my face on nights even without a full moon.
I have absolutely not observed all of the areas of our now captive darts, but the areas I have explored are as described above. And quite a few dendrobatids live in those areas.


Rich