Just a pinhead of pufferfish poison could kill a grown man

The pufferfish is a group of over 100 species that are so-named for their unique line in defence. When cornered, a puffer’s last gasp is to draw in water (or sometimes air) and pump it to the stomach, expanding to three times its normal size; deterring potential predators and when possible, affording it the vital seconds necessary to escape.

To achieve this with the required efficiency and speed, once the puffer has taken on water its gills clamp shut and a powerful bow-door-like valve closes over the inside of the mouth. Once the mouth’s cavity is compressed, this forces the water into its stomach.

Despite its resulting comic appearance, the tissues and organs of many a puffer are no joke, laced with the potent poison tetrodotoxin – a single pinhead of which could kill a grown man. This makes it ten times more deadly than the black widow spider. The poison is produced as part of a mutually beneficial relationship by common bacteria where nutrients
are exchanged as payment for the ultimate deterrent.

Some species such as the porcupine puffer are more sporting than others, covered with spines that offer added protection and ample warning to any would-be attackers. Each spine is attached to the skin by an ingenious tripod-shaped bony base. When the skin stretches, one of the legs is pushed forward and two are pulled back to snap the spine outwards… a point well made in more ways than one.