Brumation: What It Is and When to Worry
A reptile that stops eating in autumn is either brumating or ill, and telling the two apart is the whole skill.
What it is
Brumation is a reptile's response to shortening days and falling temperatures: appetite drops, activity falls away, and the animal spends long periods hidden. Unlike mammalian hibernation the animal is not unconscious. It will surface, move about and drink, then go back under.
Which species, and when
Temperate species are the ones that do it meaningfully: many North American colubrids, Russian and Hermann's tortoises, bearded dragons to a variable degree. Tropical species generally do not, or show only a mild seasonal dip. If a strictly tropical animal stops eating in winter, brumation is a weaker explanation than it first appears.
Telling it from illness
This is the part that matters. Brumation is a slowdown in a healthy animal: weight holds roughly steady, the animal is alert when disturbed, and there are no other signs. Illness looks different. Continued weight loss, sunken eyes, lethargy that does not lift when the animal is warmed, discharge from nose or mouth, or abnormal stools all point away from brumation. Weigh weekly and write it down; a trend is far more informative than an impression.
Doing it safely
Let the animal empty its gut before temperatures drop, because undigested food in a cold reptile can rot. Keep water available the entire time. Weigh weekly. Do not brumate an animal that went into autumn underweight, recently ill, or very young, and when in doubt about any of that, ask a reptile vet first.
Common questions
Is my reptile brumating or sick?
Weight is the clearest discriminator. A brumating animal holds roughly steady and is alert when roused. Continued weight loss, lethargy that persists once warmed, sunken eyes, or any discharge point to illness and justify a vet visit.
Do bearded dragons brumate?
Many do, to a variable degree, and it is normal. It commonly starts in autumn and the animal may hide and refuse food for weeks. Keep water available, weigh weekly, and treat ongoing weight loss as a reason to see a vet rather than to wait.
Should I stop feeding a brumating reptile?
Let it empty its gut before temperatures fall, because food left in a cold digestive system can rot rather than digest. After that the animal will generally refuse food anyway. Water stays available throughout.
How long does brumation last?
Commonly weeks to a few months depending on species and conditions. Duration alone is not the warning sign; weight trend is.
Sources
Related reading
all husbandry fundamentals · common mistakes · finding a reptile vet