135 snakes in one septic tank: a TikTok video revealed a winter shelter of red-bellied racers

Snakes of the temperate zone often spend the winter together, in one shelter. The behaviour is common, yet for most species such shelters are poorly documented. In Georgia, one of them came to light through social media: a local resident posted a video on TikTok, and herpetologists found a communal snake hibernaculum in a reinforced-concrete septic tank.

In total, 135 snakes were collected from the tank. The case is the subject of a paper published in April 2026 in The Herpetological Journal, the journal of the British Herpetological Society (vol. 36, no. 2, pp. 125–130). The authors are Giorgi Iankoshvili, Ioane Rostiashvili, Andro Solomanashvili, Shota Zandukeli, Alisa Sanakoeva and Mariam Tsulaia. The paper's abstract does not name the settlement or the date of the find.

Of the 135 snakes, 133 were red-bellied racers (Dolichophis schmidti) of different ages. The paper's title calls the species Schmidt's whip snake. One Dahl's whip snake (Platyceps najadum) and one dice snake (Natrix tessellata) wintered in the tank with them.

According to the authors, this is the largest recorded aggregation of red-bellied racers. It is also the first documented case in the Caucasus of snakes of different species wintering in one shelter. It is the first such mixed hibernaculum described from Georgia as well.

Among the red-bellied racers, males and females were almost equal in number, with slightly more females: 52.6%. Total length ranged from 82 to 158 centimetres and mass from 82 to 753 grams. The heaviest snake weighed about nine times as much as the lightest.

The authors read this wide size range as a sign of several age cohorts wintering in the tank. In other words, young and adult snakes shared the same shelter. A 158-centimetre snake is almost as long as an adult person is tall.

The snakes were gathered in the tank's terminal chamber. That part of the tank had the most stable microclimate, at 11 °C. The authors conclude that the case shows how important human-made structures are for communal hibernation of snakes in landscapes that people have already changed. A snake winter shelter, then, may turn up not in a rock crevice but in a septic tank.

Construction was about to reach the site. So the snakes were moved away and released in spring. At a site like this, building work can harm a whole wintering group.

The authors also see the story as an example of what social media can do. The local resident's video became an early warning and let specialists act in time. One post led first to the snakes being moved, and then to a scientific paper.

All three species that wintered in the tank are non-venomous. The red-bellied racer is a large snake and may bite if cornered. The bite can be painful, so do not pick the snake up.

If you find many snakes in a cellar, a well or a tank, do not kill or disturb them. Film them from a distance and show the photo or video to herpetologists. In this case, exactly such a video brought researchers to 135 snakes before construction reached the site. If a snake bites you, call 112.