Ozark hellbenders, aka "snot otters" and "lasagna sides," are among the world's largest and least cute salamanders. Looking at them, it’s probably not a big surprise that they’re having a hard time breeding — although inexplicably, scientists think it’s NOT because of their pancake heads or beady little eyes, but some problem in the natural environment. Now that there are fewer than 600 hellbenders left in Ozark rivers, scientists at the Saint Louis Zoo decided to step in and create a place for the salamanders to get it on.
The salamanders' love nest is a simulated river built to bring out amorous feelings in hideous beasties:
The zoo has built a kind of honeymoon resort for salamanders, assembling a mini water treatment plant and carefully tweaking water chemistry to recreate their cold, fast-flowing Ozark streams — minus any distracting predators or pollution. …
Buried in the gravel stream bed are concrete boxes with a narrow entrance tunnel at one end. They may not sound very comfy, but to a male hellbender, they're the perfect man cave — just what he needs to hunker down, fertilize and guard his stash of eggs.
Apparently they picked exactly the right dim-the-lights, leopard-print-sheets type of ambiance: The males are fertilizing eggs like crazy, and 185 baby hellbenders have hatched at the zoo. This is less cute than literally any other 185 zoo babies, but good news for the species.
Zoo Crafts Love Next to Save Ozarks Salamanders, NPR.