Leviathan

In many ways, leviathans resemble humpback whales. They are baleen whales with massive, spiked bony plates that resemble scales covering their bodies. Perhaps this is the reason why they were originally mistaken for fish.

Leviathans have a gestation period of about 2 years. They give birth to one calf at a time.

Newborn leviathan calves are usually only about half a mile long. They grow to full adult size over a period of 50 years, making them the slowest-growing fauna species in all of Altairus.

Leviathans are much too large to be able to get too close to land. Instead, they reside in Altairus's open oceans. They hunt in the deepest parts of these oceans, only occasionally coming up for air.

Despite the legends, leviathans do not eat humans or other sapients. Indeed, they live much too far from most sapient settlements (the exceptions being pelagic and benthic sirens) to pose any sort of a threat to them. Instead, leviathans are baleen whales, subsisting mainly on plankton.

Not much is known about leviathan behavior. They are usually encountered on their own or with their calves. When this happens, they may inadvertently destroy ships due to their massive size. They do not seem to have any fear of sailing ships or other beings, since they do not have any natural predators.

Occasionally, a leviathan may accidentally swallow a ship or crew. Sailors from all over Altairus have concocted tales of how they survived inside the leviathan's digestive tract. These stories migrated to Earth and became part of many cultures' legends.

Leviathans' current distribution is unknown. They have been sighted in the Lapis Ocean, the Arcanus Ocean, and the Neptunia Ocean, but it is believed that they live in all of Altairus's oceans.

While leviathans do not have superb eyesight, they are still well-equipped to navigate their pelagic home in Altairus's deep oceans. They navigate using echolocation, and their whale calls are strong enough to shatter glass if they get too close to the shore.

Being so huge, leviathans often constitute functioning ecosystems of their own. Various fauna and chemosynthetic flora are known to live inside the bodies of leviathans. It is entirely possible to live one's life relatively comfortably in the digestive tract of a leviathan, and indeed there exist towns of marooned sailors situated in the bellies of these creatures.