Gila Monster — Fact Sheet
Heloderma suspectum · Gila Monster
📋 At a glance
| Adult size | 45-56 cm |
| Lifespan | 20-30 years |
| Activity | Crepuscular |
| Difficulty | Expert |
| Legal | CITES: Appendix II; EU: Annex B; local rules still apply |
🏠 Enclosure
One adult needs at least 180 x 90 x 75 cm; larger individuals need enough additional room to turn, travel and use every thermal zone. Use 12-20 cm of compactable mineral soil and sand with a slightly damp lower layer beneath one hide. Paper is safer during quarantine.
🪨 Substrate and furnishings
All furnishings must be fixed, visible during an animal count and compatible with the shift route. Avoid adhesive décor, sharp mesh, unstable rocks or branches, aromatic wood and inaccessible cavities. Each opening needs an independent mechanical lock and neonate-proof ventilation.
💡 Lighting
Provide 10-12 hours of broad visible light and complete darkness at night. Low-output UVB may be offered as a measured Ferguson Zone 2 opportunity, with full shade at the same temperature. Whole-prey nutrition does not make intense UVB appropriate.
🌡️ Temperature
- Basking spot: 32-35 °C
- Daytime air: 24-29 °C
- Cool zone: 20-24 °C
- Night: 18-22 °C
💧 Humidity and water
Use 30-50% RH as a working range and provide a sheltered microclimate around 60-75% during shedding. Humidity must not mean a continuously wet floor. Let exposed surfaces dry, preserve airflow and judge the setup by hydration, clean sheds and skin condition.
Supply a stable bowl of fresh water from a protected service point. Persistent condensation, sour substrate, mould or wet ventral skin indicates excessive moisture or inadequate ventilation.
🪳 Feeding
Offer whole mice, small rats, quail chicks and eggs used sparingly. Adults store fat readily; weigh monthly and reduce meal size or frequency before the tail and abdomen become excessively thick. Use feeding tongs only after the animal is secured in a known position; never hand-feed or leave live vertebrate prey unattended.
Whole prey normally supplies calcium and vitamins without dusting. Regurgitation, repeated refusal or weight change requires a review of prey size, temperature, disturbance and disease rather than repeated feeding attempts.
☠️ Safety
Heloderma suspectum has a medically important venomous bite. Human Heloderma cases include severe pain, swelling, vomiting, weakness and dangerously low blood pressure. These lizards may hold on after biting, adding tissue injury; symptoms and severity cannot be predicted from the wound alone. Work only through secure barriers and a trained protected-contact procedure.
Every bite needs immediate emergency medical assessment. Call emergency services, identify the animal as Heloderma and follow their instructions; do not delay help to catch or transport the lizard. Do not use improvised flame, chemicals or cutting to release it. There is no specific Heloderma antivenom: hospital care addresses the wound, pain, blood pressure and other complications. Keep emergency contacts and the scientific name accessible before any enclosure work.
🩺 Health — warning signs
Important risks include obesity, overheating, dehydration, claw or snout abrasion, retained shed around toes, and oral injury. Refusal or immobility alone is not a diagnosis. Secure the animal before investigation, verify recorded temperatures and humidity, and arrange protected examination by an experienced reptile veterinarian. Never attempt hands-on home restraint or treatment.