Keeper timer setting
T5 UVB: one hour later on, one hour earlier off
ON: 1 hour after the daylight lights come on.
OFF: 1 hour before the daylight lights go off.
October: daylight 11.7 h; T5 UVB 9 h 42 m per day.
The T5 runs for two hours less than the total photoperiod. Example: daylight 08:00-20:00 means UVB 09:00-19:00. Keep the monthly UVI strength as listed beneath the tube. Existing care values 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
Replace the blanket UVI 5-7 default with an optional adult T5 patch at UVI 4-6, aiming initially around 5. This is a moderate working choice within published exposure guidance, not proof that 5-7 is harmful or a measured optimum for every Cyclura. Published UV-Tool assignments vary even within the genus; no trial was found that makes UVI 7 a necessary default.
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: Inferred genus-level working range. 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 ยท Muryn, Baines and Dishman (2026), Reptile Lighting Guide V10
October management
Selected automatically using the Netherlands date
Expected emergence from late-June/July clutches
Acklins Bight, The Bahamas - coastal scrub, limestone cays and sandy dune nesting habitat
28-30 CDay air
23-25 CNight
42-46 CBasking
4-6T5 UVI*
11.7 hPhotoperiod
9 h 42 mT5 UVB duration
65-80 / 78-89%RH day / night*
Peak rainfall / stormsRain / mist
6Food days/week
Annual schedule
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| Month | Day air | Night | Basking | T5 UVI* | Photoperiod | T5 UVB duration | RH day / night* | Rain / mist | Food days/week | Seasonal management |
|---|---|---|---|---|---|---|---|---|---|---|
| January | 25-27 C | 21-23 C | 41-45 C | 4-6 | 10.9 h | 8 h 54 m | 58-70 / 72-82% | Dry-season maintenance; light AM mist 2-3x/wk | 5 | Cooler, drier phase; keep adults lean |
| February | 25-27 C | 21-23 C | 41-45 C | 4-6 | 11.4 h | 9 h 24 m | 57-69 / 72-82% | Dry; localized moist refuge only | 5 | Dry-season conditioning; broad browse variety |
| March | 25-28 C | 21-23 C | 42-46 C | 4-6 | 12.0 h | 10 h | 56-69 / 72-82% | Driest period; avoid chronic enclosure wetness | 5 | Seasonal warm-up; no brumation |
| April | 26-29 C | 22-24 C | 42-46 C | 4-6 | 12.7 h | 10 h 42 m | 58-72 / 74-84% | Dry-to-wet transition | 5-6 | Increase feeding quality; prepare deep nest zone |
| May | 27-30 C | 23-25 C | 43-47 C | 4-6 | 13.2 h | 11 h 12 m | 62-76 / 76-86% | Rain pulses increase | 6 | Probable courtship/mating period |
| June | 28-31 C | 24-26 C | 43-47 C | 4-6 | 13.5 h | 11 h 30 m | 64-78 / 78-88% | Warm; regular rain pulses | 6-7 | Mating / gravid females; late-June nesting begins |
| July | 29-31 C | 24-26 C | 43-47 C | 4-6 | 13.3 h | 11 h 18 m | 65-80 / 78-89% | Warm wet season; moderate rain | 6-7 | Primary oviposition; females may dig multiple test burrows |
| August | 29-31 C | 24-26 C | 43-47 C | 4-6 | 12.9 h | 10 h 54 m | 66-80 / 79-90% | Wet/storm season | 6 | Incubation; female recovery |
| September | 29-31 C | 24-26 C | 42-46 C | 4-6 | 12.2 h | 10 h 12 m | 66-81 / 79-90% | Wet/storm season | 6 | Late incubation; stabilize nest moisture |
| October | 28-30 C | 23-25 C | 42-46 C | 4-6 | 11.7 h | 9 h 42 m | 65-80 / 78-89% | Peak rainfall / storms | 6 | Expected emergence from late-June/July clutches |
| November | 27-29 C | 22-24 C | 41-45 C | 4-6 | 11.1 h | 9 h 6 m | 62-76 / 75-86% | Rainfall easing | 5-6 | Juvenile growth; transition toward dry phase |
| December | 26-28 C | 21-23 C | 41-45 C | 4-6 | 10.8 h | 8 h 48 m | 59-72 / 73-84% | Drier transition | 5 | Seasonal reset; reduce rain, not drinking water |
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
Replace the blanket UVI 5-7 default with an optional adult T5 patch at UVI 4-6, aiming initially around 5. This is a moderate working choice within published exposure guidance, not proof that 5-7 is harmful or a measured optimum for every Cyclura. Published UV-Tool assignments vary even within the genus; no trial was found that makes UVI 7 a necessary default.
Habitat
Restricted to cays in the Bight of Acklins, The Bahamas; exposed coastal scrub and limestone with sandy beachfront dunes used for nesting.
Heat and UVB
Use a broad 41-47 C basking-surface working target and UVI 4-6 at the main basking area, with cooler air and immediate deep shade.
Diet
Primarily herbivorous. Prioritize calcium-rich browse, leafy weeds, flowers, fibrous vegetables and cactus; animal matter should remain occasional rather than routine.
Breeding
Mating is probably May-June. Field work shows nesting begins in late June and continues into early July.
Nesting
Females may excavate up to seven test burrows. Natural final burrows are about 69-235 cm long with egg chambers 14-40 cm below the surface.
Clutch
Observed clutches contain 2-5 eggs; mean about 3.1. Eggs average about 55.5 x 30.2 mm and 27.1 g.
Incubation
The IUCN husbandry manual lists 30 C. A precise taxon-specific duration is not established; field literature presumes about 85-90 days.
Status
Cyclura rileyi nuchalis is listed as Endangered by the IUCN SSC Iguana Specialist Group; Cyclura rileyi is CITES Appendix I.