FAQ: Heating & Lighting for reptiles

UVB rays let a reptile produce vitamin D3 in its skin, and without it calcium is not absorbed and the bones weaken. Diurnal lizards and turtles need UVB, while some nocturnal species need less, so always check your species’ requirements.

A thermostat switches the heater on and off or dims it based on a probe reading, so the terrarium does not get too hot or too cold. Without one a heat mat or ceramic heater can overheat a surface and burn the reptile.

A basking lamp creates one warm spot in the terrarium where the reptile warms itself as if in the sun. Reptiles do not produce their own body heat, so without such a spot they cannot digest food properly or keep their immune system working.

The wattage depends on the terrarium size and height, the room temperature and the temperature your species needs. Small terrariums often manage with a weaker bulb, larger or tall ones need a stronger one, and the final choice is made by measuring the temperature at the basking spot.

Halogen bulbs are brighter and create a more concentrated hot spot, so they often heat more efficiently than incandescent bulbs of the same wattage. Both types work for a basking spot; what matters most is that the wattage suits the terrarium and is controlled by a thermostat.

The distance depends on the lamp’s wattage and the species’ needs, so set it by measuring the temperature where the reptile actually lies. The reptile must not be able to touch the bulb, and the basking rock or branch should sit at a height where the surface does not get too hot.

The bulb must go into a heat-resistant, usually ceramic, socket, and if the reptile can reach it, it should be covered with a protective mesh guard. An exposed bulb can badly burn a reptile, especially climbing species and snakes.

Basking bulbs and ceramic heaters get very hot, and a plastic socket can deform or even melt from the heat. A ceramic socket withstands high temperatures and is safer, so when choosing a fixture check the maximum wattage it allows.

It is a hood with a reflective inner surface that directs the lamp’s light and heat downward onto the basking spot. With a reflector the same bulb heats more efficiently and less heat is wasted to the sides.

No, a basking lamp should only run during the day, usually about 10–14 hours depending on the species and season. Light at night disturbs the reptile’s sleep, so if the night temperature drops too low, a heater that gives no light is used instead.

A plain incandescent bulb heats in much the same way, but energy-saving LED or fluorescent household bulbs give off almost no heat and are unsuitable for heating. Dedicated basking bulbs usually have a narrower beam that creates a clearer hot spot.

Bulbs often fail because of water drops on hot glass, frequent switching by a simple on/off thermostat, knocks, or an unsuitable socket. To make a bulb last longer, mist the terrarium while it is off and choose a dimming thermostat.

Red and blue night bulbs used to be popular, but it is now accepted that reptiles can see this light and it may disturb their sleep. For night heating, a source that gives off no light is a better choice, such as a ceramic heater or a heat mat on a thermostat.

It is a bulb that gives off heat, visible light and UVB at the same time. It is handy for large or tall terrariums, but it cannot be controlled by a dimming thermostat, and the distance to the reptile must follow the manufacturer’s instructions.

Mercury vapour lamps should not be run through a dimming or frequently switching thermostat, because they need to cool before re-striking and wear out faster. With them, temperature is adjusted by changing the distance or the wattage, and the hours by a timer.

T5 tubes are thinner and give stronger UVB that reaches further, so they suit taller terrariums. T8 tubes are weaker and are more often used in smaller terrariums or where the reptile can get close to the lamp.

The percentage shows what share of the lamp’s output is UV and roughly matches a species’ needs. Lower-percentage lamps are meant for shade-loving or rainforest species, higher ones for desert lizards that bask in strong sun in the wild.

Bearded dragons are desert lizards, so they are usually given a stronger T5 tube of about 10–14% spanning part of the terrarium’s length. It is important that the UVB reaches the basking spot while the terrarium still has a shaded zone.

Leopard geckos are active at dusk, so they were long kept without UVB and given vitamin D3 with their food. A low-output UVB lamp with shaded areas is now increasingly recommended because it can be beneficial; ask a vet about supplements.

Many snakes can manage without UVB if they eat whole prey, but more and more keepers install a low-output UVB lamp because it is closer to natural conditions. Leave plenty of shade and hides so the snake can choose how much light it gets.