more: The diving bell has a few other special features as well. For one, the silk skin lets oxygen diffuse in from the water and carbon dioxide diffuse out, meaning the spider does not have to renew her air supply so often. The silk threads that anchor the cocoon also serve as underwater traps, alerting the spider when some unsuspecting prey touches them, so she can come darting out to deliver a paralysing bite with her potent, venomous fangs.