The Incredible Cave Salamander

by AMNH on

On Exhibit posts

Described by Charles Darwin as home to "wrecks of ancient life," caves were once thought to be evolutionary dead-ends.

As it turns out, nothing could be further from the truth. Rather than halt evolution, the trying conditions of cave habitats–like total darkness and an unreliable food supply–force living things to develop incredible ways of coping with their extreme environments.

Two small, pale fish underwater.
 Many cave animals, like these fish, share common characteristics including blindness and a lack of pigmentation.
Courtesy of Wikimedia Commons

Since they’re facing the same set of general problems, cave-dwelling animals with no relation to one another tend to develop similar solutions. Species in caves often lack pigmentation and navigate and hunt with senses other than sight. One great example is the European cave salamander known as the olm.

These pinkish-white aquatic amphibians thrive in lightless, watery caves throughout eastern Europe. They eat, mate, and sleep underwater, breathing through external gills. Olms are also nearly blind, as developing eyes in a dark cave isn’t an efficient way to spend the body’s resources. The same principle accounts for the olm’s pallid coloration—pigmentation is an unnecessary luxury when you spend your life in darkness.

Two olms, pale aquatic salamanders, side by side on a textured surface.
A pair of olms photographed in a cave in Slovenia.
Courtesy of Wikimedia Commons

To compensate for their poor sight, olms employ a suite of highly developed senses terrifically suited to life in the waterlogged caves they call home. Special cells running the length of their bodies can detect tiny pressure changes caused by fish and creatures moving in the water nearby. Olms also boast organs that can detect the weak electric fields of animals around them, and specialized tissues in the salamanders’ inner ears grant them acute underwater hearing. 

These heightened senses come in handy when an olm hunts its prey of cave-dwelling fish, crabs, and insects, which the salamander swallows whole instead of biting or chewing. Cave food sources can be fickle, though, and olms are as well prepared for famine as for feast. By lowering their metabolic rate and living on nutrients stored in their livers, they can survive for months at a time without a meal.

More amazing species, thriving in exceptional environments, were featured in the special exhibition Life at the Limits. 

A version of this story originally appeared in the Summer 2015 issue of the Member magazine Rotunda