Blind Bigmouth Seal and Four-eyed Seal

Thank you to Sinisteryy who gave me the Weddell Seal and the deep ocean as a prompt. This one was a doozy.

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    The Blind Bigmouth Seal is a large descendant of the Weddell Seal that has adapted to the deep ocean (the midnight zone) for... whatever reason. Since they no longer come up for air, they've evolved with gills, leaving their lungs as air sacs that keep the seal afloat. They have reatined their blubbor to keep themselves warm, and have an elongated mouth that allows it to feed on zooplankton. The seal does not swim, and instead floats around the water with its mouth agape.

    Since it is no longer a hunter, the Blind Bigmouth is a passive and docile creature that does not interfere with other life forms, not even predators. However, they have very few predators due to their large size.

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    The Four-eyed Seal is a smaller seal, but is more eqipped for hunting in the dark. They have large eyes that allow them to adjust their sight in the dark, and two large, bioluminescent glands on their back that allow them to illuminate their surroundings to identify prey. The eyes also acts as a way to scare away predators, as from a distance, the seal looks like a large four-eyed creature. Like their cousins (Blind Bigmouth Seals), they have evolved with gills to breathe underwater, and have retained their blubber. They have a long, powerful tail that allows them to swim swiftly when in the hunt. Despite being significantly slower than seals in higher ocean zones, the Four-eyed Seal is considered the fastest deep sea animal.

    Unlike their cousins, the Four-eyed Seals are very aggressive, as any life form that comes to their line if sight is immediately thought of as prey or an enemy. They are mostly solitary, but there have been some instances in which two or more adults have been seen fraternizing.