Overnight this Sydney Funnelweb was busy growing. Yesterday she was noticed unable to extend her chelicerae fully (where her fangs are) and her ‘colour’ was a little off. Reading this record I thought maybe she was reaching the end of her life but really she was just preparing to moult her exoskeleton.

To shed the old exoskeleton she had to burst out from inside. A new exoskeleton had been created under the old one but it was still soft and folded. She cracked open the top of the cephalothorax (her first body segment) then almost rolled out of her old exoskeleton. When she first came out she was white and extremely soft. The exoskeleton slowly hardens – this photo shows her when she is still vulnerable to predator attack as she cannot fight back with her soft fangs. This period is her main growing time as she ‘pumps’ out her new soft exoskeleton so that once it hardens it will be bigger than the one previous.

Over the next couple of days we will leave her quietly to strengthen her new exoskeleton. Some spiders, like funnelwebs are called primitive spiders and the females will continue to moult their exoskeletons this way even when they are mature. Other spiders like Huntsman will stop growing this way once they mature.

To get bigger, this Sydney Funnelweb has to discard her old exoskeleton. Photo: Alan Henderson. Source: Museum Victoria