dodolah
Retired Moderator
I post this Interview excerpts with Frances Baines long time ago.. But, I thought once in a while.. it's good to have a reminder...
Here is a snippet of the interview:
Your comment of “UVB lamps should be positioned over the basking zone” and “D3 synthesis requires warmth” intrigues me. In your opinion, do reptiles have some perception of the presence of uvb and heat as different entities? Or do they assume visible light means warmth and uvb in one. What is the problem, if there is any, from separating uvb to one end and heat bulb to another end?
Dr. Gary Ferguson and his team have done pioneering studies into the reptile "perception" of UVB, working with Panther chameleons. Their carefully designed experiments do suggest that chameleons, at least, can perceive UVB - or at least, perceive locations where there are higher levels of UVB - since, if they are deficient in vitamin D3, they choose to spend longer in these areas.
Chameleons were given the opportunity to choose whether or not to bask under UVB or UVA lamps in an enclosure where both shady and exposed areas were held at a uniform ambient temperature (about 29C). The chameleons were significantly attracted to the light from both lamps, and the vitamin D3-deficient ones were more attracted to the UVB lamps than the UVA lamps.
This does suggest that they are attracted to light even when it is not associated with heat, and that they can perceive UVB as a separate entity from UVA. What exactly do they perceive, though? They can definitely see UVA, but it seems unlikely, given the properties of the reptile eye, that they can actually see UVB. Maybe they can feel it on their skin; maybe the "feel-good factor" humans experience under UVB, possibly linked to endorphin production, is a faded human version of what a reptile experiences?
But can chameleons perceive light and heat as different entities? We can't really deduce that, because this experiment doesn't investigate the chameleon's perception of heat, at all.
I know of very few studies on reptiles where the components of sunlight have been separated out, to see what choices the reptile will make. Since a reptile must maintain its core temperature between very specific limits for life itself, we might hypothesize that if reptiles can distinguish between them, they would select basking spots based upon the temperature there, rather than upon the presence of light or UV light in the area.
One experiment conducted on spiny-tailed iguanas by Dickinson and Fa (1997) showed that these lizards were all significantly more attracted to an incandescent lamp than to a non-light-emitting heat source or a UV tube, which seems to undermine the theory. Unfortunately, the results are not conclusive, because the temperature under the incandescent lamp was hotter than under the non-light heat source, and much hotter than under the UV tube.
More research is needed! However, part of Dickinson and Fa's study clearly showed that when the choice was between the incandescent lamp and the UV tube, the lizards were primarily attracted to the lamp; they spent comparatively little time under the tube.
If we separate our UVB tubes from our heat lamps, then this is an unnatural state of affairs, which requires the reptile to make a choice it would not need to make in the wild. The captive reptile in this situation cannot absorb UVB and bask at the same time. Even if it "knows" it needs UVB, the vital necessity of maintaining a suitable body temperature seems likely to be prioritized over UV absorption, which could well be much reduced as a result. But someone needs to do the experiments, to find out whether this is indeed the case.
Here is the complete excerpt: http://chamworld.blogspot.com/2009/10/dr.html
Mind you.. it is quite a long excerpt..
Here is a snippet of the interview:
Your comment of “UVB lamps should be positioned over the basking zone” and “D3 synthesis requires warmth” intrigues me. In your opinion, do reptiles have some perception of the presence of uvb and heat as different entities? Or do they assume visible light means warmth and uvb in one. What is the problem, if there is any, from separating uvb to one end and heat bulb to another end?
Dr. Gary Ferguson and his team have done pioneering studies into the reptile "perception" of UVB, working with Panther chameleons. Their carefully designed experiments do suggest that chameleons, at least, can perceive UVB - or at least, perceive locations where there are higher levels of UVB - since, if they are deficient in vitamin D3, they choose to spend longer in these areas.
Chameleons were given the opportunity to choose whether or not to bask under UVB or UVA lamps in an enclosure where both shady and exposed areas were held at a uniform ambient temperature (about 29C). The chameleons were significantly attracted to the light from both lamps, and the vitamin D3-deficient ones were more attracted to the UVB lamps than the UVA lamps.
This does suggest that they are attracted to light even when it is not associated with heat, and that they can perceive UVB as a separate entity from UVA. What exactly do they perceive, though? They can definitely see UVA, but it seems unlikely, given the properties of the reptile eye, that they can actually see UVB. Maybe they can feel it on their skin; maybe the "feel-good factor" humans experience under UVB, possibly linked to endorphin production, is a faded human version of what a reptile experiences?
But can chameleons perceive light and heat as different entities? We can't really deduce that, because this experiment doesn't investigate the chameleon's perception of heat, at all.
I know of very few studies on reptiles where the components of sunlight have been separated out, to see what choices the reptile will make. Since a reptile must maintain its core temperature between very specific limits for life itself, we might hypothesize that if reptiles can distinguish between them, they would select basking spots based upon the temperature there, rather than upon the presence of light or UV light in the area.
One experiment conducted on spiny-tailed iguanas by Dickinson and Fa (1997) showed that these lizards were all significantly more attracted to an incandescent lamp than to a non-light-emitting heat source or a UV tube, which seems to undermine the theory. Unfortunately, the results are not conclusive, because the temperature under the incandescent lamp was hotter than under the non-light heat source, and much hotter than under the UV tube.
More research is needed! However, part of Dickinson and Fa's study clearly showed that when the choice was between the incandescent lamp and the UV tube, the lizards were primarily attracted to the lamp; they spent comparatively little time under the tube.
If we separate our UVB tubes from our heat lamps, then this is an unnatural state of affairs, which requires the reptile to make a choice it would not need to make in the wild. The captive reptile in this situation cannot absorb UVB and bask at the same time. Even if it "knows" it needs UVB, the vital necessity of maintaining a suitable body temperature seems likely to be prioritized over UV absorption, which could well be much reduced as a result. But someone needs to do the experiments, to find out whether this is indeed the case.
Here is the complete excerpt: http://chamworld.blogspot.com/2009/10/dr.html
Mind you.. it is quite a long excerpt..
Last edited:
