The two types of sea slugs (Plakobranchus ocellatus and Elysia timida) survive by eating algae, but prior research has shown that the creature can survive very long periods of starvation.

Because the slugs do not digest — at least right away — a specialized subunit of cells known as an organelle, that in the algae is responsible for photosynthesis, scientists have believed that the slugs were somehow gaining energy from the sun using the cells from the algae.

The researchers suggest that the slugs may be allowing the cells to remain alive for long periods of time, simply to eat them slowly as time passes.

This means that the cells are apparently kept alive by the sun while in the slugs body — sort of an internal farming system, allowing the slugs to survive long starvation periods.

Read more at: http://phys.org/news/2013-11-solar-powered-sea-slugs-survive.html#jCp

Photos via Proceedings of the Royal Society B: Biological Sciences, doi: 10.1098/rspb.2013.2493.
Via PHYS.ORG.