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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.
This type of herbivory is probably from feral livestock, especially donkeys.
There is video footage of guanacos eating flowers off of cacti in the Atacama. For example, an image capture of a Getty Images video:
Credit: BBC Natural History
This type of florivory has been documented in related species of cacti as well (e.g., ...