even where it may not appear to be absolutely
essential.
There is a large range of commercially-available UV
globes, tubes and fixtures, and their suitability will
depend on the species being kept and the type of
enclosure the reptile is housed in. It is important to
select the most appropriate type of UV light, as well
as ensuring that it is positioned and set up in the
correct way to benefit the animal most effectively.
A UV gradient?
Reptile keepers should be familiar with the need to
provide a temperature gradient within enclosures
that allows their animals to change position in order
to increase or decrease body temperature. It is
equally important to provide captive reptiles with a
lighting gradient in the form of different strengths of
UV light inside their enclosure. A lighting gradient
should range from maximum UVB exposure for the
particular species being kept (at or near the basking
spot), through to full shade where the animal can
completely retreat from light and UV rays.
In the wild, UV light interacts with and bounces off
objects such as trees, plants and even water,
providing animals with varying degrees of UV
exposure. Even a crepuscular or nocturnal species
that spends much of the day hidden in a burrow or
crevice may receive some UV that is refracted from
objects within its immediate surroundings. An artifi-
cial UV gradient can be created by careful position-
ing of UV lights (again, in association with the bask-
ing spot), as well as incorporating plenty of foliage
Above: this enclosure features several raised areas
where the animal can bask in proximity to the
compact UV light and heat light, as well as other
structures and furnishings to provide shade.
Image by Sam Dessen.
(real or artificial), hides, logs and other furnishings.
It is also important to ensure that your reptile is
provided with a day/night cycle, with all UV lights set
on timers to run for approximately 10-12 hours each
day.
UV strength.
Artificial sources of UV light are generally only
effective to a short distance from the light fitting,
after which the output or strength of UV diminishes
significantly. This is therefore also an important
consideration in positioning your UV lights; for
example, tall or very long enclosures may require
the installation of multiple lights, or a more powerful,
high-output source to ensure the animals are receiv-
ing adequate UV. Elevated basking spots, such as
pieces of timber or artificial rocks, can allow a reptile
to bask closer to the sources of heat and UV light,
whilst also being very natural for many species. It is
important to note that UV light is 100% filtered
through glass, perspex and plastic, and can be
filtered by up to 50% through the mesh lids on
reptile enclosures. Many fluorescent tube housings
designed for aquarium use come fitted with a plastic
lens, and it is important that you remove this if you
intend to use the device in conjunction with a UV
tube.