Species keeper protocol

Cyclura cornuta

Hispaniolan Rhinoceros Iguana / Rhinoceros Rock Iguana
A large Endangered Hispaniolan rock iguana. Keep intense basking and UV with broad thermal choice, a drier cool-season phase, plant-dominant feeding and a deep diggable nest zone. Breeding timing varies by locality across Hispaniola.

Day air28-31 CWarm seasonal ambient temperature with cooler retreats

Basking surface43-47 CBroad local basking zone; not whole-enclosure air temperature

UVI under T5UVI 4-6At normal back height; covered refuges near UVI 0

SeasonHatchling growth; SW nesting may continueClassic cycle: May mating, June laying; locality can shift timing

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 target

October 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 · Muryn, Baines and Dishman (2026), Reptile Lighting Guide V10

October management

Selected automatically using the Netherlands date

Hatchling growth; SW nesting may continue

Hispaniola - xeric limestone, dry forest, scrub and lowland woodland

28-31 CDay air

24-26 CNight

43-47 CBasking

4-6T5 UVI*

11.7 hPhotoperiod

9 h 42 mT5 UVB duration

64-80 / 78-90%RH day / night*

Wet phase easingRain / mist

6Food days/week

Annual schedule

Scroll sideways on smaller screens

Month	Day air	Night	Basking	T5 UVI*	Photoperiod	T5 UVB duration	RH day / night*	Rain / mist	Food days/week	Seasonal management
January	26-28 C	21-23 C	42-46 C	4-6	11.0 h	9 h	52-65 / 68-80%	Drier phase; light AM mist 2-3x/wk	5	Dry-season maintenance; lean body condition
February	26-29 C	21-23 C	42-46 C	4-6	11.5 h	9 h 30 m	52-66 / 68-80%	Drier phase; light AM mist	5	Condition adults; increase browse diversity
March	27-30 C	22-24 C	43-47 C	4-6	12.0 h	10 h	55-68 / 70-82%	Dry-to-wet transition	5-6	Warm-up; territorial activity may increase
April	28-31 C	23-25 C	44-48 C	4-6	12.5 h	10 h 30 m	58-72 / 72-84%	Rain pulses increase	6	Courtship conditioning; nest zone ready
May	29-32 C	24-26 C	44-48 C	4-6	13.0 h	11 h	62-76 / 75-87%	Wet-season onset / regular rain pulses	6-7	Primary mating month in classic Hispaniolan data
June	29-32 C	25-27 C	44-48 C	4-6	13.2 h	11 h 12 m	64-78 / 76-88%	Wet; regular rain	6-7	Primary oviposition month; monitor gravid females
July	29-32 C	25-27 C	44-48 C	4-6	13.0 h	11 h	64-80 / 78-90%	Warm wet phase	6-7	Incubation / female recovery
August	29-32 C	25-27 C	44-48 C	4-6	12.7 h	10 h 42 m	64-80 / 78-90%	Warm wet phase	6-7	Incubation; maintain stable nest moisture
September	29-31 C	25-27 C	43-47 C	4-6	12.2 h	10 h 12 m	66-82 / 80-92%	Wet / storm season	6-7	Hatching in classic cycle; some SW populations begin nesting
October	28-31 C	24-26 C	43-47 C	4-6	11.7 h	9 h 42 m	64-80 / 78-90%	Wet phase easing	6	Hatchling growth; SW nesting may continue
November	27-30 C	23-25 C	42-46 C	4-6	11.2 h	9 h 12 m	58-72 / 72-84%	Rain reduces	5-6	Transition toward drier season
December	26-29 C	22-24 C	42-46 C	4-6	10.9 h	8 h 54 m	54-68 / 70-82%	Drier phase	5	Seasonal reset; no brumation

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

Habitat

Native to Hispaniola; especially associated with xeric rocky limestone, dry forest and scrub, though it also occurs in some moist lowland habitats.

Heat and UVB

Use a broad 42-48 C basking-surface working target and UVI 4-6 at the main basking zone, with substantial cooler air and immediate deep shade.

Diet

Primarily herbivorous: calcium-rich leaves, weeds, browse, flowers and fibrous vegetables with modest fruit. Field studies confirm heavy plant use including cactus fruit.

Breeding

The IUCN husbandry manual gives mating in May and oviposition in June, but southwest Dominican Republic field populations have nested around mid-Sep to mid-Oct.

Nesting

Provide a very deep compactable soil/sand nest zone. The husbandry manual describes a tunnel about 1 m long ending in a chamber large enough for the female to turn around.

Clutch

Up to 34 eggs are reported, averaging about 17.4 in the husbandry manual. Incubation around 31 C for approximately 85 days is a strong captive starting point.

Status

Cyclura cornuta is listed as Endangered by the current IUCN SSC Iguana Specialist Group assessment and is CITES Appendix I.

Locality caution

Breeding timing varies across Hispaniola. If exact locality or established breeding history is known, shift seasonal cues to the animals rather than forcing this generic calendar.