Why you shouldn't use colored lights for night heat.

[jarich]

I think generally its not great to have coloured bulbs for a heat source, but I think this article is a little over the top. Have to agree with Red Ink, while its an interesting article, the science is more than a bit questionable. For a start, there are only two references, and those references are wisely full of caution from the authors about too much generalization based on their findings. Also the inferences and assumptions after are not necessarily related to those articles.

If nocturnal animals are able to see these colours, which seems likely, why would that by necessity disturb their circadian rhythm? Being nocturnal is not simply a result of darkness, there is a whole host of factors at play. If we are going to conjecture, it should also be noted that if you go to any country where nocturnal geckos live in proximity to humans, you'll quickly notice one thing - they congregate around lights when they are awake. This is obviously because thats where the bugs go too, but the point is that it doesn't seem to disturb their circadian rhythms at all.

The section on cladistics and inherited traits needs some heavy work. Calling BPs the "lowest evolved" and vipers the "most highly evolved" shows a misunderstanding of evolutionary mechanisms and principles. This is especially true when he tries to apply this to unrelated characteristics.

I would also question the bearded dragon example he uses. Let me add my own. I recently found out that a power outage screwed up one of my timers, the one for the heat lamp of my bearded dragon enclosure. (they have battery back ups, but the battery in this one apparently died). As a result, it was staying on throughout the night. I noticed when I happened to come into work one morning when it was still dark outside. The dragon was very obviously sleeping soundly when I entered that morning. Furthermore, he had not shown any signs of disturbance during the day in either appetite or activity as a result.

Again, not stating that we shouldnt try to get rid of any coloured lights, just questioning the inferences and results he is coming up with.

[StudentoReptile]

I have been shying away from colored light bulbs a while before this article even came out, mainly from the experiences of tortoise keepers.

My simple observation is that while yes, infrared is only part of light spectrum of which some of these species can see, in terms of circadian rhythm and nocturnal behavior...moonlight in nature is not infrared, or blue, or deep purple.

Personally, I think more studies should be done to properly understand the effects of this bulb over that bulb. Until then, we can only go by our personal experience.

Originally Posted by jarich

I would also question the bearded dragon example he uses. Let me add my own. I recently found out that a power outage screwed up one of my timers, the one for the heat lamp of my bearded dragon enclosure. (they have battery back ups, but the battery in this one apparently died). As a result, it was staying on throughout the night. I noticed when I happened to come into work one morning when it was still dark outside. The dragon was very obviously sleeping soundly when I entered that morning. Furthermore, he had not shown any signs of disturbance during the day in either appetite or activity as a result.

The differences in his example and yours is that his was a week-long study, whereas yours was an isolated "one-time" incident with one animal. I'm not necessarily saying that if you duplicated what he did you would get equal results, but until you did, its not fair to say that his observations are "wrong." I think a longer study with multiple animals is in order before making any definite conclusions.

[Strutter769]

Really good stuff. I'll be switching two red bulbs with CHE's tonight!

Thanks Kyle!

[jarich]

Originally Posted by StudentoReptile

My simple observation is that while yes, infrared is only part of light spectrum of which some of these species can see, in terms of circadian rhythm and nocturnal behavior...moonlight in nature is not infrared, or blue, or deep purple.

Actually moonlight is all of those things. It is reflected sunlight, so still has all the spectrum, UV, etc that sunlight has, merely less of it.

[StudentoReptile]

Originally Posted by jarich

Actually moonlight is all of those things. It is reflected sunlight, so still has all the spectrum, UV, etc that sunlight has, merely less of it.

Yes I am aware of that. But a purely "red" infrared light bulb is not.

When you are using an infrared bulb, or a blue bulb, or a purple bulb as a nighttime heat source, it is not replicating natural moonlight, and only emitting a fraction of the light spectrum, giving an unbalanced visible light for nocturnal activities.
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Another thing...I've been told by several field herpers that the "fuller" the moon is, the less likely any herps are active. I don't know if that's entirely true or not; I haven't verified it myself. If anyone else can comment on that, by all means.

If that is mostly true, then it does give credence to the notion that complete darkness is preferred over any moonlight during nighttime hours.