Critters of the Lembeh Strait | “Grazing” – Sheep of the Costasiella Family

Many know these adorable little sap-sucking slugs (technically not nudibranchs) as ‘Shaun the Sheep’, due to their resemblance to sheep grazing on grass. They are tiny (from just a millimeter up to about 12 millimeters maximum length) and can be found feeding on the host algae Avrainvillea spp which looks like a large, single, round green leaf which sticks up vertically out of the sand on Lembeh’s muck sites. They are members of the Sacoglossa family which is the only group of animals known to engage in kleptoplasty, a process where the sea slug stores chloroplasts from the algae it feeds on in its body and benefits from the food they produce via photosynthesis. In this detailed, close-up footage you can actually see the chloroplasts in the animals’ cerata (the pointy bits on the back), impossible to observe with the naked eye due to the creatures’ tiny size. Enjoy this detailed video showcasing a cute and also fascinating Lembeh critter and be sure to have a look to try and find some yourself next time you dive here!