He gave it the species name pelagicus from Ancient Greek πελαγικός 'of the open sea'.

The study also concluded that the closest relative of P. pelagicus is the Guam flying fox, based on morphology.

The authors of the 2013 study suggested that the common name of Chuuk flying fox be retained to refer to Pteropus pelagicus.

P. p. pelagicus has more contrast in its coloration than P. p. insularis, and they also tend to have larger abdominal white patches.

[3] P. p. insularis roosts in larger groups of up to 100 individuals; they are considered a "strongly colonial" species.

[8][6][9][10][11] The entire range of P. p. pelagicus is only 11.9 km2 (4.6 sq mi), with 75% of the population occurring on Satawan and Lukunor atolls.

P. p. pelagicus is threatened by climate change, as the atolls where they live are only 3–5 m (9.8–16.4 ft) above sea level.

Climate change is also projected to increase the frequency and intensity of typhoons, which negatively impact both subspecies.

Other threats potentially include introduced predators such as cats, rats, and mangrove monitors.

P. p. insularis is not as threatened by climate change as the pelagicus subspecies, because its range has greater elevation.