MammalsMammalia

Every marine mammal in this sea is descended from an animal that walked, and none of them ever finished undoing it. Inside a dolphin's flipper are the bones of a hand: an upper arm, a forearm, a wrist and five fingers, shortened and bound in tissue. A whale still carries a pelvis with nothing attached to it. They breathe air, they hold a fixed body temperature, they nurse their young, and they do all of it in water that pulls heat out of a body far faster than air can.

Breathing is a decision for them, not a reflex. Every breath is taken deliberately, which makes ordinary sleep lethal, and the answer is to shut down one half of the brain at a time with the opposite eye open and keep swimming. The nostrils have migrated to the top of the head, and the airway is plumbed straight through to the lungs past the throat, so a whale cannot breathe through its mouth at all and cannot choke on what it swallows.

Birth happens in open water, usually tail first, and the calf's first task is to reach the surface for a breath, often nudged up by the mother. Milk is taken from slits rather than exposed teats, in short bursts, and it is thick with fat, enough to hold together in water and enough to build a layer of blubber on a calf quickly.

Three lineages of them live here and they are not equally easy to meet. Dolphins are the real encounter: bottlenose along the reefs, spinner dolphins resting through the day in a few sheltered lagoons. Large whales are genuinely rare in this basin and are almost always a boat sighting rather than a dive. The dugong is rarer still, scattered across the seagrass bays of the mainland coast, and it is not a whale but a grazing animal from an entirely separate branch. There are no seals or sea lions in the 🌊 Red Sea at all.