Sleep, or sleep-like states, in tarantulas.

[Sergic]

I'd like to propose a hypothesis that might explain some tarantula behaviors -
tarantulas sleep, and we keepers sometimes interact with them while they are sleeping. The behavior that I have observed which is in need of an explanation is that, on occasion, tarantulas will initially be resistant to being moved or fed, but will suddenly bolt, flick hairs, or lunge at the feeder after some amount of sensory input from prodding or the feeder.

I was shown this recent paper by Nath et al., which you can read here http://www.cell.com/current-biology/fulltext/S0960-9822(17)31023-0

The gist is that upside down jellyfish likely sleep, and exhibit the necessary characteristics of sleep. The authors also reference other work that has shown other inverts such as C. elegans and Drosophila also likely sleep. The implication is that sleep evolved early in animals and has been conserved in many, if not most or all, animal lineages. Therefore, it is likely tarantulas sleep. If you are at all interested in this sort of topic, I highly recommend you read the paper, regardless of whether you agree tarantulas likely sleep.

From the paper, the criteria for sleep are:

1. A quiescent state with reduced activity.
2. Reduced responsiveness to stimuli.
3. Full reversibility of quiescent state.

These three criteria fit behaviors that I have encountered while rehousing or feeding.

1. Spider exhibits state of reduced activity. This would, admittedly, be hard to demonstrate in tarantulas without comparing something like heart rate between different times of day or night. However, even though tarantulas are usually inactive, they could have alert periods of inactivity, which would be differentiated from periods of sleep by reduced response to stimuli.
2. I have noticed that at times, even generally high-strung spiders such as GBB or N. incei can be lightly prodded or closely approached by a feeder without noticeably reacting.
3. In some cases where I have observed 2, after some amount of prodding or being approached by the feeder, the tarantula will react suddenly, and either run, flick hairs, or lunge at the feeder.

It would be interesting to test whether tarantulas sleep, but would likely be harder to test than in Cassiopea, given the lack of visible and easily measurable activity in tarantulas. However, if people were to notice fewer inactive or unresponsive instances in their tarantulas when working with them at night, that could be evidence that they do sleep, and are both more active and more alert at night.

 

[Red Eunice]

Interesting article indeed!

 

[Swede Baboon]

Noob thought: Why on earth wouldnt tarantulas sleep ?

 

[viper69]

I've observed myself and others have well, when your seemingly awake T reacts for lack of a better word "startled", much like a human would as if being woken up by an unexpected stimulus. I haven't observed it often, but at least 2 times in 2 different species. While I don't know if they were sleeping as we do, they sure weren't resting like they normally appear to do.

 

[darkness975]

It is almost like they enter some type of suspended animation, if you will. The sudden effect of stimulus on their senses shocks them into alertness.

 

[Venom1080]

I swear there was another thread on this. With a good post by AphonopelmaTX. I'm too lazy to go find it, but some one else can if they really want.

 

[JBarbaresi]

I’m reviving this because I just did a google search on this after having the same thought. I was thinking tarantulas can put themselves into a trance-like state when they have nothing better to do. Otherwise they would have extremely boring lives.

 

[Ray Lence]

I've read almost the same thing. But it is not sleep as we understand this word.
During the periods of w8ng for a prey they reudce organism's activity to appropriate minimum. Tarantula's brain is rather big for animal that size and most of their nerual system is rather centralized comparing to insects for example.
Bigger brains = more expensive to maintain as neuron cells are one of the most demanding, even when not actively used, for example, during ambushing.
So tarantulas partially cieze unnesisarry activites and because of that they go into "stand by" sleep-like state. Not for rest and membrane restoration (as we do), but as a result of energy-saving.
And looks like not all but vital parts of brain are shut down (as it happens to us), but some very selective parts, that allow brain "turn on" immediatly as proper stimul arrives.
Lol, it is basically reverse-sleeping in some meaning.