8:34in productionCh. 1 · Only one in the genus/ 8:34 · ceiling 15 min
Reptiles & amphibians · Fish & sea life
Green sea turtle
The only aquatic turtle that eats only seagrass — and the only reason its fat is green.
The green sea turtle is a large, globally distributed marine reptile found in tropical and subtropical seas. It is the only species in the genus Chelonia and the only aquatic turtle that is fully herbivorous as an adult — feeding strictly on seagrasses in shallow lagoons. Its common name refers to green fat beneath its carapace, not shell colour. It migrates long distances between nesting beaches and feeding grounds. The IUCN classified the global population as 'least concern' in 2025, though regional subpopulations remain threatened or endangered.
It is the sole member of its genus and a large Cheloniidae turtle.
2:38
Where it feeds and why it stays shallow
It lives only in tropical and subtropical seas, feeding as an adult in shallow lagoons full of seagrass.
4:06
Green fat, not green shell
Its green fat comes from seagrass — and no other aquatic turtle is herbivorous as an adult.
5:10
Migration with a menu
It migrates long distances between beaches and feeding grounds — unlike any other marine turtle, it does so as a strict herbivore.
Worth your time?
Yes. See the whole thing.
4.5/ 5
What works
defines strict herbivory in marine turtles
clarifies geographic and genetic structure (Atlantic/Pacific/Indian Ocean)
explains origin of common name unambiguously
states IUCN status with year and scope ('global', 'regional')
What does not
provide lifespan
provide clutch size
provide population figures
provide conservation status for regional subpopulations beyond 'threatened or endangered'
See it if
marine ecologists
conservation practitioners
divers with access to shallow seagrass habitats
Skip it if
readers seeking behavioural novelty beyond migration and grazing
those needing demographic or life-history data
The written brief1 min read
What the species is and where it came from
Chelonia mydas is a large sea turtle of the family Cheloniidae. It is the only species in its genus. It lives in tropical and subtropical seas worldwide — Atlantic, Pacific and Indian Oceans.
How it works, in terms someone would actually use
It migrates long distances between nesting beaches and shallow coastal seagrass meadows. It feeds exclusively on seagrasses as an adult. Its green fat — not its shell — gives it its name.
What it gets right
It reliably occupies shallow lagoons where seagrass grows. It sustains genetically distinct Atlantic and Pacific populations. It is the only species in the genus Chelonia.
What it does not
It does not eat jellyfish, crustaceans or fish as an adult. It does not inhabit deep pelagic zones year-round. It does not have a global endangered status: the IUCN lists it as ‘least concern’ globally in 2025.
What it changed
It redefined dietary specialisation among marine reptiles. No other aquatic turtle species is herbivorous as an adult.
Who it is for, and who it is not
It is for marine ecologists studying herbivory in oceans, conservationists tracking regional subpopulations, and divers who can access shallow seagrass meadows. It is not for those seeking novelty in behaviour beyond migration and grazing, or for anyone expecting data on lifespan, clutch size or population trends — none are provided in the sources.
Is it worth your time
Yes, if you want to see the only fully herbivorous aquatic turtle. No, if you expect to observe it feeding in deep water or outside tropical and subtropical lagoons.