Species keeper protocol

Iguana iguana sanctaluciae

Saint Lucia Horned Iguana
A Saint Lucia-specific protocol for the native horned iguana lineage. Taxonomy is debated: Reptile Database / ITWG retain Iguana iguana sanctaluciae, while some authors use Iguana insularis sanctaluciae.

Day ambient28-31 CWarm year-round; no cold brumation

Basking surface37-41 CBroad basking zone with cooler shaded retreats

Humidity72-88 / 85-95%Drier Dec-May, wetter Jun-Nov; maintain airflow

Breeding cueWet-season recoverySaint Lucia Forestry identifies Feb-May as nesting season

Keeper timer setting

T5 UVB: one hour later on, one hour earlier off

During active care — ON: 1 hour after daylight starts.
OFF: 1 hour before daylight ends.

During hibernation / full brumation: T5 UVB OFF (0 hours). In transition months, keep UVB off while dormant and use the active timer only once the animal is warmed and active.

October: daylight 12.0 h; T5 UVB 10 h.

The active T5 duration is the photoperiod minus two hours. Example: daylight 08:00–20:00 means UVB 09:00–19:00. Follow the monthly UVI strength measured beneath the tube and provide access to shade. This timing rule does not introduce hibernation for species whose schedule has only a mild or active winter rest. If an older combined heat / UV column is present, the new T5 UVB duration column governs UVB timing; existing heat settings are preserved.

UVI beneath the optional T5 tube

Working exposure target

October target at normal back height

UVI 4-6directly under the tube when it is on

The retained range remains a provisional captive working target. No new species-specific result was found that clearly requires a numerical change. Retaining it is not certification of an experimentally established optimum.

Your measuring point

Measure at the animal's normal back height directly beneath the brightest accessible part of the T5 strip, positioned toward the middle/back. The animal can enter and leave this area freely.

Keep a lower-UVI gradient and fully covered refuges near UVI 0. This is the optional exposure area, not the average across the cage.

Use a UV Index meter, such as a Solarmeter 6.5/6.5R. Warm the tube for about 30 minutes; keep reflector, guards and mesh in place. Raise or lower the fixture within its manufacturer's minimum-distance guidance, then recheck the reading and every higher accessible surface.

Evidence level: Provisional retention. These are working recommendations, often inferred; exact species optima and seasonal UV dose usually have not been measured. Log lamp-on time and animal behaviour as well as UVI.

Baines et al. (2016), UV-Tool · Muryn, Baines and Dishman (2026), Reptile Lighting Guide V10

October management

Selected automatically using the Netherlands date

Wet-season recovery

Saint Lucia north-east dry forest and coastal corridor; warm year-round with a Dec-May dry season and Jun-Nov wet season

28-31 CDay ambient

24-25 CNight

37-41 CBasking

4-6T5 UVI*

12.0 hPhotoperiod

10 hT5 UVB duration

72-88 / 85-95%RH day / night*

Frequent rain; ventilateRain / mist

7Food days/week

Annual schedule

Scroll sideways on smaller screens

Month	Day ambient	Night	Basking	T5 UVI*	Photoperiod	T5 UVB duration	RH day / night*	Rain / mist	Food days/week	Seasonal management
January	27-30 C	22-24 C	38-41 C	4-6	11.5 h	9 h 30 m	55-70 / 70-80%	Light AM mist 3x/wk	6	Dry season; courtship / mating
February	27-30 C	22-24 C	38-41 C	4-6	11.8 h	9 h 48 m	50-68 / 68-78%	Light mist; offer nest	6	Nesting season begins
March	28-31 C	23-24 C	38-42 C	4-6	12.1 h	10 h 6 m	50-65 / 68-78%	Dry upper areas; moist nest	6	Gravid females / active nesting
April	28-31 C	23-25 C	38-42 C	4-6	12.4 h	10 h 24 m	55-70 / 70-82%	Light mist; deep moist nest	5-6	Main nesting / post-lay care
May	28-31 C	24-25 C	38-42 C	4-6	12.6 h	10 h 36 m	58-72 / 72-84%	Rain gradually increasing	6-7	Late nesting / recovery
June	29-31 C	24-26 C	38-42 C	4-6	12.8 h	10 h 48 m	65-80 / 80-90%	Daily AM rain/mist	7	Wet season begins; incubation
July	29-31 C	24-26 C	38-42 C	4-6	12.8 h	10 h 48 m	68-82 / 82-92%	Daily rain/mist	7	Incubation / early hatch window
August	29-31 C	24-26 C	38-42 C	4-6	12.6 h	10 h 36 m	70-85 / 84-94%	Rain/mist 1-2x/day	7	Wet season / hatchlings / growth
September	29-31 C	24-26 C	38-42 C	4-6	12.3 h	10 h 18 m	70-85 / 84-94%	Rain/mist 1-2x/day	7	Wet season / juvenile growth
October	28-31 C	24-25 C	37-41 C	4-6	12.0 h	10 h	72-88 / 85-95%	Frequent rain; ventilate	7	Wet-season recovery
November	28-30 C	23-25 C	37-41 C	4-6	11.7 h	9 h 42 m	68-84 / 82-92%	Frequent showers	6-7	Wet phase easing
December	27-30 C	22-24 C	37-41 C	4-6	11.5 h	9 h 30 m	60-75 / 75-85%	Rain reduced; AM mist	6	Drying trend / breeding onset

Keeper notes

Use measured gradients and animal behaviour, not single thermostat readings

T5 UVI measurement

Measure UVI at normal back height directly beneath the brightest accessible part of the optional T5 strip. Place the strip toward the middle/back with free access to and away from it; preserve a gradient into fully covered refuges near UVI 0. These numbers describe the exposure area, not the whole enclosure or a daily average.

UVI review

Taxonomy / provenance

Reptile Database and the IUCN SSC Iguana Specialist Group Taxonomy Working Group retain Iguana iguana sanctaluciae. Some recent authors use Iguana insularis sanctaluciae. Preserve pedigree carefully because hybridization with introduced iguanas is a major threat on Saint Lucia.

Natural habitat

Native animals are now concentrated in Saint Lucia's north-east deciduous tropical dry forest and coastal corridor, often near ravines and streams. Grande Anse and Louvet are important nesting landscapes.

Enclosure

Large and arboreal. For one adult use about 200 x 120 x 200 cm or larger; room-scale housing is strongly preferred for breeding adults. Provide heavy trunks, broad shelves, visual barriers and deep sandy-soil nesting substrate.

Heat and UVB

Use about 27-31 C daytime air, 22-26 C nights and a broad 38-42 C basking surface. A measured UVI around 4-6 at the main basking zone is a practical target, with shaded retreats below UVI 1.

Humidity and seasonality

No brumation. Model the Saint Lucia dry season Dec-May and wetter Jun-Nov period mainly through rain/mist frequency. Keep drinking water and a humid refuge available even in the dry phase.

Diet

Adults should be overwhelmingly herbivorous: diverse calcium-rich greens, safe browse, leaves and flowers daily, fibrous vegetables, and smaller amounts of fruit. Avoid routine animal protein.

Breeding

Saint Lucia Forestry identifies February-May as the nesting season. A practical cycle is Nov-Dec conditioning, Dec-Feb courtship/mating, Feb-May gravid females and nesting, with incubation and hatching extending into the wetter season.

Nesting / incubation

Provide 45-60+ cm of compactable sandy-soil substrate before females are visibly gravid. Published native Saint Lucia data give a mean clutch of about 23 eggs from 14 clutches. Species-specific incubation trials are scarce; start around 28.5-30 C using general green-iguana experience and refine from your own proven line data.

Conservation warning

Do not mix sanctaluciae with iguanas of uncertain provenance if conservation-value purity matters. Adult males can be highly territorial. Watch females for persistent digging, straining or failure to lay.