Fish have evolved to live in poisonous waters laden with sulphuric acid and at depths far beyond where any light could reach. But even with a high capacity for adaptation, there is still one thing any fish will always need: water … right? Not the lungfish. With a swim bladder (sometimes a pair of swim bladders) that has been adapted into a lung, the lungfish has evolved to take in oxygen straight from the air. The lungfish’s lungs allow it to live completely out of water for months, and even years, at a time.
When waters are high, the lungfish behaves like any other fish, happily munching away on small fish and crustaceans on the bottoms of ponds and streams. However, when the dry season hits and most other fish succumb to a slow death by sun-frying, the lung fish burrows itself deep into the mud, digging out a path by taking mud into its mouth and forcing it out its gills (which it still has in addition to it’s lung(s)). Once it has reached a comfortable depth, the lungfish settles in to its spot and starts emitting a slime that will cover its entire body save its mouth – it wouldn’t deny itself the sweet fresh air of an underground mud cave. Since there aren’t many prey species inside the lungfish’s burrow with it, it is forced to slowly digest muscle in its own tail – proving the old adage, you eat what you are.
Below is video of the lung fish’s dramatic emergence from the earth. Not sure if Tolkien knew about the lung fish, but we can’t help but see a similarity between this reawakening and the birth of an Uruk-hai. Unfortunately for this specimen, it doesn’t get much time to stretch its fins before getting smoked by another Miracle of Weird candidate – the shoebill stork.
The lungfish’s ability to stay alive in even the driest of mud is best exemplified by stories people cutting mud bricks out of the dry earth which, unbeknownst to them, hold living lungfish inside of them. These bricks can sit in somebody’s living room wall for up to 4 years until just the right rain storm triggers the lungfish to break free and head for water. We suspect it would be especially horrifying if this were to happen right when you’re watching the “snake surprise” scene of Temple of Doom.