I'm researching the Glaucus atlanticus, also known as the blue glaucus, among various other names, but after reading quite a few articles and searching on the Internet as many different ways as I can think of, I can't find any of its predators, or any indication it has no natural predators. Everything I've read is just silent on the issue. Does anyone know what, if any, predators this has? Thanks!

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  • $\begingroup$ While I don't really know anything about that animal, it doesn't really need a specific predator (to keep its population in check) if it has to compete with other organisms for the same food source(s). $\endgroup$
    – Nicolai
    Apr 10, 2019 at 7:24

1 Answer 1


Try out using Google Scholar to take a more scientific literature-based approach to your search.

Frick et al. (2009)1 found that about 42% of logerhead sea turtle (Caretta caretta) stomachs contained remnants of G. atlanticus.

We were able to identify G. atlanticus in the diet of loggerheads because whole or nearly intact specimens were present.

enter image description here

Loggerhead turtle mouth and throat with sharp papillae. Source NCSU CMAST (Photo by Craig Harms)

Bieri (1966)2 observed G. atlanticus frequently attacking one another and biting off pieces of each other. In one case, one individual ate all but the head and trunk of a smaller specimen.


1, Frick, M.G., Williams, K.L., Bolten, A.B., Bjorndal, K.A. and Martins, H.R., 2009. Foraging ecology of oceanic-stage loggerhead turtles Caretta caretta. Endangered Species Research, 9(2), pp.91-97.

2. Bieri, R., 1966. Feeding preferences and rates of the snail, Ianthina prolongata, the barnacle, Lepas anserifera, the nudibranchs, Glaucus atlanticus and Fiona pinnata, and the food web in the marine neuston.

  • $\begingroup$ Good answer (+1), however I fail to see the function of the somewhat gross picture of the loggerhead. Note2self: stay well away from the beak of loggerheads... $\endgroup$
    – RHA
    Apr 16, 2019 at 21:04
  • $\begingroup$ RHA just for the FYI nature is cool factor. $\endgroup$ Apr 17, 2019 at 1:06

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