Sunlight Supplement

Hi,
In d petshop i asked the guy if newts needed the vitamin supplement (I think its D13) that i use on my terrapin bcuz he doesnt get sunlight. the brand is T-Rex UVB Drops. he said he "Didn't think so"!!! So i was just wondering if they need UVB drops or not, bcuz he's been unreliable up 2 now. eg: He keeps the newts with the Terrapins !!!(he's actually d guy who told me they'd get along fine together!). He also told me newts lived for 7 years! What an IDIOT (i can say that on this forum, can't I?).

Newts can live for 7 years... or 17, or sometimes 70 (in the case of the giant species). But other than that, I agree with you. He's probably not the brightest crayon in the box. But remember that most pet shops just want to sell you stuff.

They don't need 'drops' of any sort... They need a good balanced diet with a good mix of vitamins and minerals. Try earthworms, bloodworms, waxworms, butterworms, almost anything soft and squishy, in addition to crickets or other feeder insects (in moderation).

Cathal,
I do not want to start a debate over supplementation vs natural sunlight however it would be really good for your terrapin if it could be exposed to natural, unfiltered sunlight for at least part of the year. Others with more experience with chelonians may offer better advice but I am not sure about UVB drops. I would personally never use them with diurnal lizards.
Chip

I have to agree with Joan, I don't think any caudate needs Vitamin D supplements. Their natural exposure to the full solar spectrum is very minimal so my guess is they don't require as much as reptiles do since they don't need to support scale production and retention. But that's a very unexpert opinion.

Tanx 4 de feedback everyone.
Chip, The uvb drops are not supposed to be used with diurnal lizards anyway. U have to get moon drops or something.
Well, I think the terrapin is fine bcuz now dat its summer the light comes in the window at an angle & goes into the tank onto his rock. Would it be the same as natural light if it went through the window & side of the glass tank or would it be filtered & would he still get the energy?
Tanx 4 d above feedback. I think the pet shop guy just wanted 2 sell something because the drops, for a small bottle, about 100ml cost me €15!
Yeah i feed them both earthworms (live, but small) 2-3 times a week & feed them 4 times in total (i feed them newt & terrapin food).
once again tanx 4 everything, this site ROCKS!

While some glass manufacturers have begun to put UV reflective coatings on window glass, prices for this stuff is usually too high for residential use. So unless your home is less than say 5 years old and was built to be highly energy efficient, your windows are very likely to be extremely transmissive in the UV. No worries.

Actually window glass is pretty much opaque to UV due to the iron contained in the glass. Very small amounts of UV can get through depending on the composition of the glass...

Ed

Many glasses experience a sharp drop in transmittance as they cross the mid UV threshold (~250-300nm). This roughly corresponds to UVB. Window glass is soda lime glass which has virtually no iron in it at all (~1%). Transmittance drops in glass are due to index of refraction and second surface reflection. Usage of the word opaque is very incorrect as this implies absorption. What happens is as the waves pass through the medium, they are bent significantly and then, since UV is short wavelength, there is a greater likelihood of the wave reflecting off the second surface due to oblique angle of attack.

Therefore, as you get into the far UV (UVC), virtually none will pass. The actual amount of UVB will be very dependent on impurities as you stated. However, transmittance of UVA in uncoated glasses is usually as high as 70-80%.

The definition under which I was using opaque "not pervious to radiant energy" (Merriam-Webster) which does not indicate if it was absorbing or reflecting the wavelengths of energy under discussion but simply did not allow the passage of that light. If you were inferring from a more technical reference, then that was more decriptive definiton than I intended.

As I understand the majority of window and aquarium glass contains iron oxide contaminates (or in some cases in deliberately added by the manufacturer to reduce transmission of UV) and to produce UV transparent glass is an expensive process.

The following reference does not support the statement that 70-80% of UVA is transmitted through standard glass (at least standard aquarium glass which I understand is the same manufacturing process) (see Messommier, S.P. 1995,Incorrect ultraviolet usage. Bulletin of the Association of Reptilian and Amphibian Veterinarians 5(3):4. (additionally there is a short statment to the reference on page 58 of Amphibian Medicine and Captive Husbandry, 2001, Krieger Press).
In any case, the topic at hand was in reference to UV that is metabolically active in the production of D3 which occurs in the UVB region. And as you have confirmed, this is not transmitted through standard glass......

Ed