An unusually warm November has disrupted seasonal rhythms across the Moscow region: reptiles that normally shelter for winter and enter hibernation remain active. Ecologists link the anomaly to a prolonged spell of positive temperatures that has kept soil and leaf litter warm.
Why snakes haven’t gone into hibernation
Snakes require a steady temperature cue to enter winter dormancy. Typically, night temperatures falling below +5 °C cool the soil and forest litter, triggering reptiles to settle into hibernation sites such as burrows and hollow logs. This year, however, daytime readings often climb to +7…+11 °C, while nights rarely drop below +3 °C, keeping the forest bedding warm.
“In November the Moscow region has unique conditions: days warm to +7…+11 °C and nights rarely fall under +3 °C. The sun still heats the leaf litter where snakes usually overwinter, which prevents them from falling asleep. Once persistent subzero temperatures set in and the ground freezes, the region’s snakes will go into hibernation until spring,”
the Ministry of Ecology and Nature Management of the Moscow Region explained.
Which snakes live in the region — and why they matter
Three snake species inhabit the Moscow region; all appear on the region’s Red Book and therefore receive legal protection:
- Common adder (the only venomous species in the region), recognizable by its zigzag dorsal pattern.
- Grass snake (non-venomous), usually identified by two yellowish spots on the head.
- Coronella (a rare, shy species), which favors dry sunny clearings and forest edges.
“All three snake species play important ecological roles: they control rodent populations and serve as prey for raptors,”
noted biologist Ekaterina Pakhomova.
How this year’s cycle compares to the norm
Normally snakes begin to slow down in late September and seek winter shelters in October, entering full dormancy by November. In 2025, the cycle has shifted: reptiles continue to hunt into November, remain on the surface through October and November, and may only enter hibernation late — possibly after the first sustained frost.
Practical safety tips if you meet a snake this autumn
- Do not try to catch or handle the snake. Reptiles rarely attack unless provoked.
- Avoid the area where the snake rests and give it space to retreat.
- Do not kill snakes — they are protected by law.
- Report unusually late snake activity to your local Ministry of Ecology office.
- Watch household pets closely; warm weather increases the chance of encounters in gardens and yards.
Additional notes and historical context
Interesting facts: snakes sometimes hibernate in groups of up to several dozen individuals; their body temperature depends entirely on ambient conditions; and coronella can remain in dormancy up to seven months without feeding.
In central Russia, snakes traditionally enter hibernation from late September. Similar hibernation disruptions occurred only twice before — in 2013 and 2020, both years with anomalously warm autumns. Ecologists warn that such events are becoming more frequent as the climate warms, producing later seasonal transitions across the region.
