Tarantulas drawn to daylight?? Riddle me this....

[Peter Lacey]

I think one of the problems is people's interpretations of what they've read, or been told. You can quite quickly see patterns forming in forums. One person suggests tarantula are most active during the night, the next person suggests you only see them at night and the third person introduces the word "never".

A while ago a lad named Ben/Phobia suggested in forums that tarantula might benefit from UV lighting. For the most part he was shot down by the "never" argument, but whilst I consider tarantula are most active at night I don't discard the fact they are seen during the day. Infact last year Paul Carpenter gave a lecture at Invicta on his experiences seeing Brachypelma during the day, in large numbers, along roadbanks - he quelled a few arguments in my head with that revelation. Ben sent me his notes and I queried his methods however I suggested with more study it was something that could be presented as a BTS journal article. I later spoke to Andrew Smith about the possibility that UV light was of benefit to tarantula hoping to find some credence. I put it to him, that with cheap motion camera's available, possibly powered by solar, we could study how regular this happens in their natural environment. We resigned ourselves to a project for further study, any willing pupils?
What we did acknowledge is the possibility that arboreal species might be more prone to this than terrestrial/fossorial species. A number of people have suggested that they've seen their Avics attracted to daylight. One of my favourite photo's of my P. rufilata community was catching a male basking in the sun. He was quick to hide once he caught my movement but not before I grabbed this:


Whether Marks situation of tarantula obtaining benefits of the sun's rays is open to debate. The glass used in the window and the enclosure's they are kept in would filter out much of the benefit. The heat would obviously attract them, but what worries me is they wouldn't have any escape from it, I'd be very curious as to how high the temperatures might reach within the enclosure and within their hide. One could argue that rather than benefit from the light they are seeking to escape from the heat. I'd doubt that they are capable of controlling their temperatures, we've read of tarantula experiencing burns due to heat pads, so in this uncontrolled environment I'd be a bit concerned. However, if it works for you then it works.

Does anyone have any timescale for how long they find their Ts in the sunlight? My experience has been short term but that might be because I disturbed them.

[Aragorn Davies]

Really interesting read and topic this!

[James Box]

Colin I know you often get alot of stick for being direct, sometimes unfairly but come on........

'This is a scenario many people who have probably only read the many books (and web pages) about tarantulas will try and argue about ...'

Of course I read books when I started the hobby as I am sure the vast majority of us did, all trying to ensure we care for our Tarantulas in the best possible way. (not a bad thing at all).

After time we evolve in the hobby, meet new people with like minded interest, debate and learn together. Some of your posts especially on AP have been very useful, I also like how you come from a logical point of view more often than not.

Moving forward with this...... I am fully aware that each tarantula has its own personality etc, so will often discount the many theories out there if we just looked at the one specimen. So the question I raised is it does seem to be the light but my kitchen / torch light does not have the same effect as the sun, what are your thoughts on this ?

*Like yourself I would also say I am experienced in the hobby but we are both still leaning daily.

i must admit, i didn't see that in Colin's post...he wasn't talking about you, mate!

and why would Colin get stick for directness? he's the nicest guy around, i've never seen him go out of his way to offend people, he's the soul of diplomacy.
then again, not to name or shame forums, but if it was on a certain forum, then the "stick" would've been what i'd expect of that particular place, as it is populated by a large number of of clowns.

my T's are housed in a fairly utilitarian way. some do hide, but not all...and now i think about it, i've seen them out in the day time as well as at night, they seem to be used to it. not sure i've seen them actively seeking out light, but i think a basking instinct makes sense in "cold blooded" creatures...

[Colin D Wilson]

Thanks James ....


Pete, some input for your "length in sun" question.

The book case (avics and pokies bar a couple) is situated along a wall at 90 deg to window, the sun hits the front of the tubs, in the morning, for about two and a half hours (during summer) maximum. The cereal tubs have on ly the front (wider) face showing due to being stacked closely, all the hides (cork bark full length floor to lid) are situated to the rear (thinner) side of the tubs as is usual in these setups.
We notice the spiders will come to the front of thier tubs a few minutes after the sun has hit, they will all sit on the sides of their tub (ventral side showing) for the period the sun hits and then for ten (ish) mins after. they seem a little more active after this perios but settle down to normal service after half hour or so.

[Peter Lacey]

Very interesting, thanks Colin
My own experience of seeing this in tubs was rather stressed Ts, it obviously became too warm for them

Is it because you live in Scotland and therefore your Ts rarely see the sun? (sorry, I had to)

[Craig Mackay]

Is it because you live in Scotland and therefore your Ts rarely see the sun? (sorry, I had to)

Lol, at the same time as the spiders you can see us clinging to the windows!

The sun is shining into my spider room just now and the only spiders I have out in the sun just now are Pokies and Avics. All of the terestrials are hidden away. This seems to be the norm for here. Arboreals during the day, terrestrials during the evening and burrowers very late at night.

[Paul Arnold]

I have to say that I disagree with the notion that a Tarantula cannot control its body temperature,surely it would like any other cold-blooded animal thermoregulate. I keep all my terrestrials on 5" of substrate with a deep dug in hide. I wouldve thought that if when the sun hit their enclosures and it became too warm for them,they would retreat down the hide? Mine do the opposite and spread out on the glass at the front. Ive monitored the temperature of these dug in hides and they are betwen 3 to 5 deg C cooler than the enclosure itself. I keep my Avic with both the warm and cool side heavily planted and shaded,she has web and bark retreats in both areas and uses both frequently moving from warm to cooler side. This is thermoregulation? To end on I have used heat mats for 10yrs and have never ever seen one of the many T's that ive kept "hog the mat" to the extent of burning itself. Sure ive seen them spend long periods of time in the warm area but they always move away to a retreat on the cooler side. Please correct me if im wrong but T's are endothermic thus drawing warmth from the ground and surrounding objects? My mats are fixed to the side of the enclosure,with the bottom of the mat 3cm below ground level. This warms the ground surrounding the mat area.I place a piece of cork bark at the same level and my t's will sprawl over it looking real comfy Ive never seen a T sprawl over the glass to draw heat Maybe ive just got lucky with the burn issue,but 10yrs,its no coincidence

[Colin D Wilson]

Good discussion !!, enjoying it

"Endothermic" is a term used for spiders, reptiles etc, it mainly describes the chemical reaction, i.e. to absorb energy ... which is what they do.
"Poikilothermic" is the word i like to use as it describes an animal that has a temperature that varies inline with the surrounding environment.

Heat mats are something i've just (in the last two odd years) come to have more experience of. I used to just have two rooms available in my old house where i could provide a summer and winter temperature.

I think actually too much emphasis is placed on the neccessity for heating spiders, reptiles etc (probably to promote sales of extortionately priced heating equipment)

Andrew Smith (our Chairman and part time God ) found temps in some species of tarantula burrows in the wild were only about room temp, this is where they stayed for the best part of the day ... technically they don't need heating at all if your rooms warm enough according to that.

And lastly Peter ...... if you knew anything about geography then you'd realise we must have more sunshine here, we all live in the hills so .. obviously ... we're closer to the sun ... duh