Scientists have witnessed how death spreads through a living creature like a wave, each cell dying one after another until the entire organism is deceased.

A British team captured the final moments a tiny, transparent ground worm's life by tracking a blue fluorescence molecule that travels through the organism's cells as it dies.

While scientists understand many of the processes that causes individual cells to die, far less is known about the chain of events that propagate death throughout an entire animal.

As the biological mechanisms of death in worms are similar to those in mammals, the researchers believe the worm could prove a useful model for understanding death in humans.

University College London ageing researcher David Gems and his team have identified the chemical pathway of self-destruction that moves through worms during their final demise.