I was thinking about the link between sharks and sea slugs, but it is not an easy one! However here are some facts:
- Both might be exploited by the Chinese for food, depending on the level of exploitation it can cause significant damage on their population. The Chinese eat large sea slugs (sea hares) as well as their eggs.
- Both are top predators. There are not many species that can eat sharks, just as there are not many species that can eat nudibranchs. All nudibranchs (but not all sea slugs) are predators even if their preys don’t always swim away… they are an apex predator in their own food chain. In opposite to sharks, they did not do much in terms of getting big and growing large teeth, but they developed amazing defence strategies and became real chemical factories. Moreover if you can enlarger their teeth, you will see they are very impressive and scary!
- Both have specialized teeth according to their prey. Nudibranchs have a kind of tongue called radula, which has a lot of small teeth. Each species have their own kind of teeth depending on what they feed on, just like sharks the teeth are essential to identifying species and give you tips about their feeding behaviour. Moreover like sharks their teeth continuously change and grow to always be nice and sharp!
- Manta rays and sharks often frequent cleaning stations and some nudibranchs can also been seeing having their body cleaned. Cleaner shrimps are often seeing on Spanish Dancer (which grows up to 50cm!). However one day I took a picture of the first ever registered (as far as I know) cleaner shrimp cleaning the radula of a nudibranch! (Nembrotha pupureolineata)
- Manta rays might feed on pelagic sea slugs that are part of the plankton