The vast majority of spiders and tarantulas are not dangerous, and many can be held. However, remember, the pleasure of this activity is only for you; most spiders probably do not enjoy this activity. Although, at times, some appear to be curious about the change in their environment. Most of them probably don’t care.
It is important to know that Spiders and tarantulas become tired very rapidly. That is why it is essential not to hold them for very long periods. We do encourage people to hold such animals because this is a healthy and positive experience, but in an appropriate manner, and not for too long. If you hold a spider or a tarantula for too long, it can cause them to be overwhelmed, and they can die. Yes, a spider can die just from holding them. However, this also usually requires improper handling, stress on the animal, and for long periods of time. Yes, many animals can become relatively tolerant of such interactions, but still, keep in mind the length of time.
Here is a quote from Biology of Spiders by Rainer F. Foelix speaking about how spiders are prone to exhaustion: “spider muscles contain only few mitochondria (Linzen and Gallowitz, 1975), and since mitochondria ultimately provide the energy for the cell, it is not surprising that spider muscles fatigue rapidly. It has been known for many years that, although spiders can achieve high levels of momentary activity, they usually become exhausted after a few seconds of exertion (Bristowe, 1932). During activity, mainly anaerobic energy sources (phosphate, glycogen) are used, whereas fat is burned during rest (Prestwich, 1988a, b; Paul, 1990; Eschrich and Paul, 1991). After a period of high activity, a long period of recovery follows with an elevated aerobic metabolism. D-Lactate accumulates as an end product in the muscle tissue, then spreads into the hemolymph, causing a drop in pH. This meta-bolic acidosis contributes to the rapid exhaustion in spiders.” (1:32). Therefore, we need to be careful about how we handle and interact with these amazing animals.
“Learning never exhausts the mind.” – Leonardo da Vinci