Unlike humans, spiders lack an internal skeleton; instead, they possess a hard outer shell known as an exoskeleton.
As tarantulas grow, they outgrow their exoskeleton, prompting them to crawl out of it in a process called molting.
This shedding, or ecdysis, is a natural biological mechanism that enables the spider to grow and replace worn body parts.
While tarantulas don’t experience pain in the same way humans do, the process demands significant physical energy. Tarantulas require significant energy to pump fluid, push out of the old exoskeleton, and wiggle free.
Immediately after they shed their skin, the new exoskeleton feels soft, pale, and fragile, leaving the tarantula defenseless until it hardens over several days to a couple of weeks.
Young tarantulas may molt as often as once a month. This slows down to once every year or so as the tarantula grows. Female tarantulas will continue to molt their entire lives, although they molt much less frequently as they get older.
Even if they are not growing much bigger, molting can help spiders repair damage to their bodies.
Males, on the other hand, have one final molt once they reach sexual maturity. They usually don’t live more than one to three years after this, and they prioritize mating with a female. Although molting isn’t painful, it exhausts and complicates the process.
New keepers might mistakenly believe that molting is painful because tarantulas often flip onto their backs during this time, which can appear alarming. They rhythmically pulse, twitch, and stretch their legs as they slip out of their tight exoskeleton, creating a dramatic but natural part of the molting process.
However, if complications arise—such as the old skin getting stuck or the spider becoming trapped—it can lead to significant physical damage or stress, underscoring the importance of maintainers keeping proper humidity and minimizing disturbance during molting.
Content for this question contributed by John Coro, resident of John Coro, Harrison, Hudson County, New Jersey, USA
