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 targetOctober 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 / adult recovery
Grenadines, southern Lesser Antilles; warm seasonal island climate with a pronounced Jan-May dry season and wetter Jun-Dec period
28-31 CDay ambient
24-25 CNight
37-41 CBasking
4-6T5 UVI*
12.0 hPhotoperiod
10 hT5 UVB duration
70-85 / 84-94%RH day / night*
Frequent rain; ventilate wellRain / 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 | 23-24 C | 38-41 C | 4-6 | 11.5 h | 9 h 30 m | 55-70 / 70-80% | Light AM mist 3x/wk | 6-7 | Dry season; reproductive conditioning |
| February | 27-30 C | 23-24 C | 38-41 C | 4-6 | 11.8 h | 9 h 48 m | 50-68 / 70-80% | Light AM mist 3x/wk | 6-7 | Courtship / mating; watch males |
| March | 28-31 C | 23-25 C | 38-42 C | 4-6 | 12.1 h | 10 h 6 m | 50-65 / 68-78% | Dry upper surfaces; humid nest | 6-7 | Gravid females / nest preparation |
| April | 28-31 C | 24-25 C | 38-42 C | 4-6 | 12.4 h | 10 h 24 m | 55-70 / 72-82% | Light mist; deep moist nest | 6-7 | Main nesting window; April wild nesting recorded |
| May | 28-31 C | 24-25 C | 38-42 C | 4-6 | 12.6 h | 10 h 36 m | 58-72 / 75-84% | Rain slowly increasing | 7 | Late dry season / post-lay 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 | Likely hatch window / growth |
| 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 / browse abundant |
| 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 | 70-85 / 84-94% | Frequent rain; ventilate well | 7 | Wet season / adult recovery |
| November | 28-30 C | 23-25 C | 37-41 C | 4-6 | 11.7 h | 9 h 42 m | 65-82 / 80-90% | Frequent showers | 6-7 | Wet phase easing |
| December | 27-30 C | 23-24 C | 37-41 C | 4-6 | 11.5 h | 9 h 30 m | 60-75 / 75-85% | Rain reduced; AM mist | 6-7 | 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
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.
Taxonomy / provenance
Reptile Database and the 2025 IUCN SSC Iguana Taxonomy Working Group retain Iguana iguana insularis. Some recent authors use Iguana insularis insularis. Preserve exact island origin and pedigree because introgression with introduced green iguanas occurs on some islands.
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 nest substrate.
Heat and UVB
Use about 27-31 C daytime air, 23-26 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 Grenadines dry season Jan-May and wetter Jun-Dec period mainly through rain/mist frequency. Keep a humid refuge and drinking opportunities even during the dry phase.
Diet
Adults should be overwhelmingly herbivorous: varied calcium-rich greens, safe browse, leaves and flowers daily, fibrous vegetables and a smaller amount of fruit. Avoid routine animal protein.
Breeding
Wild nesting by Grenadines insularis-type iguanas was documented in April on Carriacou. A practical cycle is Dec-Jan conditioning, Jan-Mar courtship/mating, Mar-Apr gravid females and nesting, then incubation into the wet season.
Nesting / incubation
Provide 45-60+ cm deep compactable sandy-soil substrate before females are visibly gravid. Species-specific incubation trials are limited; use green-iguana baselines cautiously: often 10-30 eggs and about 90-120 days. Start around 28.5-30 C with stable moisture and good gas exchange.
Conservation warning
Do not mix breeding animals of uncertain provenance if conservation-value purity matters. Adult males can be highly territorial. Watch females for persistent digging, straining or failure to lay.