Arachnids (Spiders, Scorpions,
mites, etc.) and most insects do not have
skeletons like ours. We have our skeletons inside
our bodies, like all animals.
Arachnids and Insects have external skeletons, which is
their skin or shell. Now because insects have
external skeletons, to allow them to grow they
must grow a new soft skeleton underneath their
a spider moults it splits open it's old
skeleton and wriggles out of it, the new
skeleton that was growing underneath is
soft and pliable, for a short while. The spider, once it is free stretches the new
skeleton to allow some room for new
growth, the new skeleton then hardens.
If a tarantula loses a leg or other
appendage before a moult, after the
tarantula has moulted it may have
partially or fully re-grown the missing
limb, this is called regeneration. Many
reptiles can also do this.
When a tarantula moults it lies on its
back with it's legs in the air, at this
time the tarantula is very vulnerable and
can be attacked and killed by the insects
that it usually feeds on.
Example of an
(Click on each picture to enlarge)
The tarantula takes between
two and twelve hours on average to complete the
sheding of it's old exoskeleton (it's skin).
Once this has been accomplished, the tarantula
will not eat for two or more days, as it's fangs
are still soft: the fangs are also part of the
exoskeleton and are shed with the rest of the
The tarantula is usually very weak and
dehydrated after moulting. Most tarantulas, once
they reach maturity only moult once a year or
once every two years, depending on species.
Spiderlings (baby tarantulas), moult up
to eight times in their first year of life, each
moult becoming progressively further apart.
Other Pages on Tarantula