The act of molting is a usually stressful process that invertebrates go through to grow. Since they have a hard exoskeleton they literally have to break free of their old skin, revealing a new skin underneath. At the time of molting the new skin is still soft and pliable and once blood is pumped to all of the extremities, the animal becomes larger.
In the case of tarantulas this is a fascinating process. Not only do they grow larger, but any hairs that were flung off in self-defense are replaced. If a leg has broken off, this too is replaced. After a molt, the tarantula’s colors are also very bright and fresh. Unfortunately though, this is when the animal is most vulnerable as it cannot defend itself.
Tarantulas usually go on a feeding fast before molting. Even specimens that are heavy eaters will often stop altogether as they prepare. You will also usually notice the abdomen darkening and oftentimes the tarantula will web itself up into its enclosure for protection. This helps to keep away any potential predators but it also helps to increase the humidity, which is very important.
The tarantula will then make a silk pad for it to lay on. This pad is soft and covers the substrate. Once the tarantula is free of its old skin, the new skin is very soft and will tear easily. This silk pad helps to prevent this from happening by forming a barrier between the spider and the ground. Once the pad is formed the tarantula turns upside down and the process begins.
Here you can see the “new” skin starting to appear through the old carapace.
Here much more of the legs are evident as well as a good part of the abdomen.
Almost all of the legs have been freed from the old skin.
A closer look shows the chelicerae and white fangs as well as the red hairs this species is known for.
The spider is now completely free, showing the huge color difference.
The old skin has been pushed to the side and the spider takes some time to relax and regain its strength.
When hardened, the fangs will turn black. At this point the tarantula cannot feed.
Once the spider gets its strength back, it will flip back over.
Once it is turned over, it relaxes again allowing its skin to harden up.