Do leopard geckos need UVB?

Why the old answer was "no"

Leopard geckos are crepuscular - most active at dawn and dusk - so they are not as dependent on UVA and UVB as diurnal species. For years that was translated into a flat "leopard geckos do not need UVB", and the species was kept successfully under that assumption for decades.

The current position in the guidance we cite is that this is partially true and increasingly outdated: mounting evidence shows that when UVB is offered, leopard geckos and other nocturnal species will bask under it and benefit from it. There is published work on the question in the Journal of Herpetological Medicine and Surgery. So the honest answer is not "no" and it is not "they will die without it" - it is that low-level UVB is a real improvement to quality of life and health.

The dose, which is the part that matters

Light is not only about UVB

Even setting UVB aside, leopard geckos need a day and night cycle. Having a light on during the day helps regulate that cycle, which supports mental health and stimulates appetite. The published photoperiod is 14 hours in summer, 12 hours in winter, simulating the seasonal change. A smart timer synced to local sunrise and sunset handles it, and the guidance suggests bringing the UVB on shortly after sunrise rather than simultaneously.

Occasional daytime basking is normal, not a sign of a problem - many nocturnal species have been observed basking.

What not to do

• Do not use a desert lamp at a de-rated distance. A ShadeDweller-class lamp is purpose-built for this zone; improvising with a 10.0 lamp further away gives you a target you cannot predict.
• Do not put the lamp behind glass or plastic. It blocks UVB entirely.
• Do not use a colored night bulb for supplemental heat. Reptiles see the light and it disrupts the sleep cycle; a ceramic heat emitter in a guarded fixture is the alternative.