A paelosur swimming near UNSC Fathom.

A paelosur is an enigmatic sightless cetacean apparently native to the oceans of Beta Gabriel and Alluvion. The paelosur use an incredibly evolved sense of echolocation to find their primary source of food, massive colony-swarms of krill-like organisms found in the planet's oceans. As cetaceans, the paelosur are air-breathers, inhaling and exhaling through thousands of pores scattered across the surface of their bodies. Interestingly, paelosur appear to have been seeded on multiple worlds by the Forerunners following the firing of the Halo Array.[1]

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