With the country caught in the most severe heatwave since 2022, some of us nutty herpetoculturists are asking the same question: what do we do with our animals during this time?
Penny and I have a rule at home—if ambient temperatures start creeping above 30°C, we begin stripping systems back.
Heat sources? Off if safe to do so. Additional lighting? Reduced or removed where appropriate. Anything generating unnecessary warmth gets reconsidered.
Our logic is fairly simple: most of our enclosures are designed to retain heat, not lose it. Wooden vivariums in particular are remarkably good at trapping warmth and once ambient temperatures climb high enough, every bulb, ballast and fitting starts contributing to the problem.
This mindset comes from experience… and one slightly annoyed bearded dragon.
Back in 2006—the famously brutal July heatwave—I had a considerably smaller collection and considerably more confidence than knowledge. Logically (or so I thought), I switched off thermostats and heating but left the old T8 UV running so my bearded dragon, Fella, could still get his light.
Turns out UV tubes also generate heat.
The enclosure sat at just over 39°C.
Fella spent the day gaping dramatically before I opened the doors and got hit by what felt like opening an oven. My usually sedentary dragon launched himself out, disappeared under the sofa and made his opinion of my husbandry abundantly clear.
I left him there overnight.
He survived. My pride did not.
We live and learn.
These days—with frequent reminders from Penny—we approach heatwaves differently. We remove unnecessary heat input and prioritise preventing overheating over maintaining perfect routines.
And after years of doing this across everything from isopods and mantids to false chameleons, cresties and bearded dragons, we’ve had no measurable issues.
Because sometimes the best husbandry decision is accepting that your carefully engineered setup was built for February, not for Britain pretending to be southern Spain.
Heatwave Husbandry: General Principles
Heat stress develops faster than many keepers expect.
Most reptiles and amphibians can tolerate short-term changes far better than prolonged overheating with no escape option.
A few practical adjustments can make a significant difference:
Create thermal escape zones
Animals should always have access to cooler areas.
- Increase shaded areas.
- Add hides on cooler sides of enclosures.
- Improve airflow where appropriate.
- Avoid direct sunlight through windows (glass turns vivs into greenhouses alarmingly quickly).
If your enclosure normally runs gradients, heatwaves often flatten those gradients entirely—monitor both warm and cool ends.
Reduce unnecessary heat production
Not every species requires full normal schedules during extreme heat.
Depending on species and room temperature:
- Reduce photoperiod slightly.
- Switch off supplemental heat if ambient temperatures remain within acceptable ranges.
- Consider reducing high-output LEDs or additional lighting if enclosure temperatures climb.
UV provision becomes more species dependent.
Many reptiles tolerate short interruptions or shortened exposure periods better than prolonged overheating, but species with higher UV requirements should ideally still receive access during cooler parts of the day if practical.
Hydration becomes husbandry
Fresh water should be checked more frequently than normal.
For species that drink droplets:
- Mist during cooler morning or evening periods.
- Avoid soaking enclosures continuously.
- Monitor humidity separately from hydration.
High humidity plus high heat can become more stressful than heat alone for some species.
Frogs: The Heatwave Panic Club
If reptiles dislike heatwaves, many frogs actively campaign against them.
Most commonly kept frogs tolerate stable warmth reasonably well but struggle with sustained spikes and stagnant air.
Useful interventions include:
- Increasing ventilation while maintaining appropriate humidity.
- Offering additional cool retreats through dense planting or shaded hides.
- Misting during cooler periods rather than repeatedly all day.
- Monitoring water quality more closely—warmer water degrades faster.
Signs of overheating may include:
- Remaining permanently submerged.
- Unusual daytime exposure.
- Loss of appetite.
- Restlessness or repeated attempts to escape.
For temperate and montane species especially, prevention matters more than emergency cooling.
No amphibian appreciates being accidentally turned into soup.
Axolotls: The Cold-Water Specialists
Axolotls deserve special mention because heatwaves can become genuinely dangerous very quickly.
Unlike many reptiles, axolotls are adapted to cooler water and prolonged temperatures above preferred ranges can rapidly increase stress, reduce oxygen availability and contribute to disease risk.
Practical measures:
- Keep tanks away from windows.
- Reduce room temperature if possible.
- Increase surface movement for oxygen exchange.
- Float sealed bottles of chilled water for gradual cooling if necessary.
- Use aquarium fans or dedicated chillers where available.
Avoid dramatic temperature crashes.
Slow, controlled reductions are safer than repeatedly swinging temperatures up and down.
Heat-stressed axolotls may show:
- Reduced feeding.
- Increased floating.
- Curled gills.
- Excessive movement or lethargy.
If your axolotl looks annoyed, assume it’s warmer than it wants to be.
Final Thoughts
Heatwaves are one of the few times where “business as usual” can become the wrong decision.
Your enclosure doesn’t know it’s summer.
Your thermostat doesn’t know the UK has temporarily become the surface of Mercury.
Watch the animal, monitor enclosure temperatures independently of set points, and don’t be afraid to temporarily adjust routines.
Missing a normal day of heating or lighting is usually far less risky than allowing an enclosure to quietly cook.
And if your reptile runs out of the viv and disappears under the sofa…
that may be useful feedback.
On a final note and in-keeping with our herpetology based work and experience - heatwave adjustments are species-specific and not a replacement for normal environmental requirements.
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