Husbandry of tortoises and other reptiles (Merck): temperature gradient, UVB, humidity
Source: Merck Veterinary Manual article "Management and Husbandry of Reptiles" (first-hand, retrieved 2026-07-29 via curl, HTML stripped to plain text). All bullets are exact verbatim substrings of the cited source_file and C1-substring verified.
Husbandry parameters (apply to tortoises/chelonians)
Temperature requirements shown are air temperature gradients. In general, basking temperatures should be 5°C warmer, whereas at night these temperatures should fall by 5°C.broad-spectrum lighting (UVB 290–300 nm) essential; NS, no special lighting requirements, although broad-spectrum lighting is still recommended because it is likely to have health benefits.Humidity is seldom directly controlled, although the advent of dedicated humidifiers and sprinkler systems makes this practical.
> Most nonbreeding pet snakes and aquatic turtles are best maintained as single pets, because trauma while feeding is common in groups. > Depending on geographical location, large tropical tortoises and crocodilians kept outside will require some form of heated house during colder periods. > However, UVB light (290–300 nm) is especially important for most diurnal lizards and chelonians for vitamin D 3 synthesis and calcium regulation . > Higher humidity levels have always been regarded as essential for many tropical species (eg, chameleons); however, high humidity microclimates are also often critical for many arid species (eg, tortoises, leopard geckos) to decrease shell pyramiding and dysecdysis. > Feeding insects a nutritionally complete diet high in calcium and dusting the insects with a high-calcium reptile supplement (eg, calcium carbonate) immediately before offering them to a reptile is required to prevent nutritional deficiencies in reptiles (see common leopard gecko and box turtle images). > Box turtle ( Terrapene spp) Image Box turtles are a common pet species but may require a license in areas where they are endemic. > African spurred or sulcata tortoise ( Centrochelys sulcata ) Image African spurred tortoises are commonly kept as pets; however, they require calcium-fortified, fibrous plant-based diets and broad-spectrum lighting. > However, \u003cb \u003eUVB light (290–300 nm) is especially important for most diurnal lizards and chelonians for vitamin D\u003c/b\u003e\u003csub \u003e3\u003c/sub\u003e\u003cb \u003e synthesis and calcium regulation\u003c/b\u003e. > Higher humidity levels have always been regarded as essential for many tropical species (eg, chameleons); however, \u003cb \u003ehigh humidity microclimates are also often critical for many arid species\u003c/b\u003e (eg, tortoises, leopard geckos) to decrease shell pyramiding and dysecdysis. > They are docile and require broad-spectrum lighting and calcium-fortified invertebrate and plant-based foods.\u003c/p\u003e\u003c/div\u003e\",\"XlinkXrefDescription\":\"\u003cspan id=\\\"v112871044\\\" class=\\\"anchor\\\" \u003e\u003c/span\u003e\u003cdiv class=\\\"para\\\" \u003e \u003cp \u003eBox turtles are a common pet species but may require a license in areas where they are endemic. > They are docile and require broad-spectrum lighting and calcium-fortified invertebrate and plant-based foods.\u003c/p\u003e\u003c/div\u003e","XlinkXrefDescription":"\u003cspan id=\"v112871044\" class=\"anchor\" \u003e\u003c/span\u003e\u003cdiv class=\"para\" \u003e \u003cp \u003eBox turtles are a common pet species but may require a license in areas where they are endemic.
Most nonbreeding pet snakes and aquatic turtles are best maintained as single pets, because trauma while feeding is common in groups.Depending on geographical location, large tropical tortoises and crocodilians kept outside will require some form of heated house during colder periods.However, UVB light (290–300 nm) is especially important for most diurnal lizards and chelonians for vitamin D 3 synthesis and calcium regulation .Higher humidity levels have always been regarded as essential for many tropical species (eg, chameleons); however, high humidity microclimates are also often critical for many arid species (eg, tortoises, leopard geckos) to decrease shell pyramiding and dysecdysis.Feeding insects a nutritionally complete diet high in calcium and dusting the insects with a high-calcium reptile supplement (eg, calcium carbonate) immediately before offering them to a reptile is required to prevent nutritional deficiencies in reptiles (see common leopard gecko and box turtle images).Box turtle ( Terrapene spp) Image Box turtles are a common pet species but may require a license in areas where they are endemic.African spurred or sulcata tortoise ( Centrochelys sulcata ) Image African spurred tortoises are commonly kept as pets; however, they require calcium-fortified, fibrous plant-based diets and broad-spectrum lighting.However, \u003cb \u003eUVB light (290–300 nm) is especially important for most diurnal lizards and chelonians for vitamin D\u003c/b\u003e\u003csub \u003e3\u003c/sub\u003e\u003cb \u003e synthesis and calcium regulation\u003c/b\u003e.Higher humidity levels have always been regarded as essential for many tropical species (eg, chameleons); however, \u003cb \u003ehigh humidity microclimates are also often critical for many arid species\u003c/b\u003e (eg, tortoises, leopard geckos) to decrease shell pyramiding and dysecdysis.They are docile and require broad-spectrum lighting and calcium-fortified invertebrate and plant-based foods.\u003c/p\u003e\u003c/div\u003e\",\"XlinkXrefDescription\":\"\u003cspan id=\\\"v112871044\\\" class=\\\"anchor\\\" \u003e\u003c/span\u003e\u003cdiv class=\\\"para\\\" \u003e \u003cp \u003eBox turtles are a common pet species but may require a license in areas where they are endemic.They are docile and require broad-spectrum lighting and calcium-fortified invertebrate and plant-based foods.\u003c/p\u003e\u003c/div\u003e","XlinkXrefDescription":"\u003cspan id=\"v112871044\" class=\"anchor\" \u003e\u003c/span\u003e\u003cdiv class=\"para\" \u003e \u003cp \u003eBox turtles are a common pet species but may require a license in areas where they are endemic.