Can they see red light?

[Ivyna J. Spyder]

I need something to keep the night time temps above 70. Will a red bulb work or will it keep them up?

I'll probably get another lightless heat emitter anyway since they're safer, but it's useful to know.

 

[Shelli]

I know when I go on the sea turtle watch they only use red lights and we can't use regular flash lights.. :/

 

[Madkins007]

Yes. Tortoises can see a wider range of colors than a human can, although probably not as far or with as much resolution.

The more scientific answer is that we have 3 kinds of color-sensors in our eyes, roughly equal to red, yellow, and green. Tortoises have 4 of these structures and one seems tuned to see UV light. This is one reason it is helpful to offer as balanced of a light source as possible to growing tortoises.

 

[ChiKat]

I just bought a black light for Nelson because he needs a little extra heat at night (he's getting a CHE for Christmas ) Will a black light bother him at night?
Sorry to hi-jack but I didn't want to start another thread since this kind of relates!

 

[SILVERSTAR]

i would use a red bulb not a glass bulb that is colored red,there is a difference trust me.

 

[Madkins007]

OK- the answer to the question 'can they see red light?' is YES, they can.

The question 'can I use a red light to heat my habitat at night" is a lot different. There is little evidence that red, blue, or black bulbs used for heat bother the tortoises, but they are still putting out a lot of light that the tortoise can see- possibly more than we can imagine since there is going to be SOME UVA emissions they can see that we cannot.

Studies have shown that relatively small amounts of light, especially blue light, can negatively affect human sleep- but in mostly subtle ways. We have no idea if it affects tortoises or not. I don't see a reason to risk it if I can use a ceramic heat emitter and get more of the electrical energy converted to heat without wasting energy being given off as visible light, but I also don't have any solid reasons to avoid colored bulbs.

Silverstar- what do you mean? Red bulbs are made by using red-tinted glass (like the Zoo-med bulbs), or a coating that ranges from a stain to more of a paint. If you removed the red tint on the surface or in the glass, these are regular incandescent light bulbs that make light by heating a coil up until it glows visibly. All the color does is to block a lot (but not all) of the visible light so it emits mostly heat. I would agree that the red stains and paints do not hold up as well as the red glass does, but I am not sure what difference it makes in actual use?

 

[SILVERSTAR]

well the using the red glass bulbs as oppose to the red colored glass eliminates the risk of regular light shining in because the bulbs that are coated sumtimes the whole bulb isnt completely colored all the way up to the part that screws into the socket creating small lite leaks that may disturb tortoise sleep more than just red light,wut i should have said was dont get jus any red bulb.

 

[Madkins007]

Thanks for the clarification, Silverstar! I appreciate it. Yes, from that standpoint, the red glass versions would be a better choice than the painted versions. Good call!

 

[pros81]

Yes they can, and I have tested it myself.

There was this one time my redfoot was wandering around at night time (I had the light turned on in the room they're in) so I decided to turn off the light only to find that my tortoise completely froze in place (giving me the impression he was no longer able to see where he was going).

I then turned on an infrared spot light and pointed it at my tortoise. He immediately began moving again (telling me that the red light had lit up his path). Just to test it, I turned the red light off to find him freeze in place again.

I did this enough times to come to the conclusion that in the presence of red light, darkness does indeed become illuminated for redfoots.

 

[Yvonne G]

I like to think of it as moonlight (I use a black light bulb).

 

[abra]

Rambo doesn't seem to mind. I use it for nights and he sleeps fine.

 

[Madkins007]

I don't want to make this a big deal, but 'seems to do OK' is not the same as being the optimal condition.

There are several studies that show humans are disturbed by fairly small amounts of light at night- especially in some wavelengths. It changes our sleep patterns and body chemistry, but not in many visible ways.

How would we KNOW if our torts sleep patterns are being disrupted? They nap a lot already- would we really notice an increase in naps or something? I am not saying this because I have an answer- I honestly don't know if it makes a difference.

 

[Tom]

Great thread. I'm with Mark on this one. All points.

 

[Yvonne G]

I would assume that if the light was bothering them you might see un-natural night time activity...like wandering around, being out of the burrow or den, maybe looking for food???? Tortoises don't toss and turn, but they might possible try digging a bit more than normal or being restless in their den.

 

[GotTurtles]

I use red heat lights at night for my tortoises and chameleons that are in the garage. I have used them for years. During the day they are up and roaming and at night when the regular lights go out they are asleep and not moving/ eyes closed.