When you're blind and live in a cave, there's a lot of time to sit and think.
Maybe that's what this one cave salamander was up to during a seven-year stint of doing absolutely nothing.
Researchers observing blind cave-dwelling amphibians known as olms (Proteus anguinus) had to exhibit a remarkable amount of patience before they could report anything about one of their tagged specimens. It's a good thing that the study was designed to last for eight years, because this one olm sat completely still for seven of them.
Olms live sedentary lifestyles due to their bland habitats, having evolved to live in pitch-dark underwater caves. They've lost their eyes and just about all of their skin pigmentation, appearing like ghostly-white blind baby dragons. Scientists believe they can live for more than100 years, and their metabolisms are so slow that they only need to eat about once per decade, reports CNET.
When you factor in that they have no natural predators and only seek out a mate every 12.5 years or so, it's easier to understand these creatures' laziness — although no one could have guessed this level of inactivity was possible.
For the study, researchers from the U.K. and Hungary dove into the darkness of caverns in Bosnia-Herzegovina where these amphibians live. They collected specimens by hand and injected a Visible Implant Elastomer under each animal's tail‐fin skin, as a tagging method. The olms were then placed back at the exact site of capture, and researchers returned to check on them periodically over an eight-year period.
It turns out that observing olms is the biological equivalent of watching paint dry.
The majority of the tagged individuals moved less than 10 meters during the course of the study, with the one aforementioned sedentary individual moving the least among them, just once over the period of observation.
But while there wasn't a lot of activity to observe, there's a lot more to the study than just waiting for salamanders to move. Because olms reproduce at such a leisurely pace, they're incredibly vulnerable to even minor changes to their environment. They can therefore act as crucial indicators about the reach of human impact on the environment.
"The low reproductive activity of the species, together with the reported extreme site fidelity makes this top predator of aquatic cave communities highly vulnerable and a sensitive bio-indicator of habitat-changing human activities," the study's authors wrote.
The study was published in the ZSL Journal of Zoology.