Sometimes you find a tiny patch of rock in an underwater cave that’s so perfect that you just have to sit there for seven years without moving. According to a new study in the Journal of Zoology, a salamander living in a cave in Bosnia and Herzegovina has done just that, after it was observed on the exact same spot for 2,569 days.
The study authors were monitoring a group of European salamanders called olms, which really have no reason to ever be in a hurry. With no natural predators, there’s no need for these amphibious oddities to run or hide, and given that they can live for a century, they’ve got loads of time to get properly stuck into a good old sit. On top of that, they only reproduce once every 12.5 years, so they don’t have the regular mating rush that keeps other animals on their toes.
To find out just how sedentary olms are, researchers tagged and monitored a total of 26 individuals living in a 350-meter-long (1,150-foot) section of the Vruljak 1 cave, between 2010 and 2018. At least 100 days elapsed between each check-up, yet only on 10 occasions was an olm found to have moved more than 10 meters (32 feet), with a 20-meter (65-foot) movement recorded just once.
On average, the creatures moved about 5 meters (16 feet) in a year, although one hyper individual shifted a full 38 meters (125 feet) in just 230 days.
Despite having no eyes, olms have decent chemical, magnetic, and acoustic senses, so their lack of movement can’t be attributed to difficulties with orientation. Speaking to New Scientist, study author Gergely Balázs of Hungary's Eötvös Loránd University claimed that the salamanders’ “sit-and-wait strategy” of predation may account for this extreme stillness, as the olms choose to preserve energy by waiting for the small crustaceans they feed on to come close, rather than chasing them. Sometimes this means they have to wait years between meals, but with such great rocks to sit on, who can complain?!
In spite of their extreme levels of chill, olms may in fact have reason to worry, as their intense aversion to movement and low rate of reproduction means that they may not be able to react to any changes to their habitat caused by man-made climate change.
If only we could all be more olm.
[H/T: New Scientist]