The Lesser Yinglets were dependent almost entirely on mollusk meat, their bodies seemingly getting absolutely every vitamin and nutrient they need from this very specific type of meat.

The Greater Yinglets, however, have the stomach for just about anything. Yet despite this, mollusk-flesh seems to still contain a balance of nutrients that can nourish a yinglet almost perfectly as a foodstuff possibly can; or so we must surmise, from the comparatively intense reward the brain sends a yinglet who tosses any down its gullet…

Page 46 of “Notes on Local Wildlife of the Val Salian Passage”