Mexican Beaded Lizard — Fact Sheet

Heloderma horridum · Mexican Beaded Lizard

Full care guide and sources

📋 At a glance

🏠 Enclosure

One adult needs at least 200 x 100 x 100 cm; larger individuals need enough additional room to turn, travel and use every thermal zone. Use 15-25 cm of compactable soil, clay and sand, with leaf litter and one deep humid retreat. 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: 21-25 °C
• Night: 19-23 °C

💧 Humidity and water

Use 40-65% RH as a working range and provide a sheltered microclimate around 65-80% 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 rodents, quail, chicks and occasional eggs. Large adults become obese easily. Use modest whole-prey meals, body-condition records and longer intervals outside the active season. 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 horridum 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, heat stress, dehydration, rostral abrasion, bacterial dermatitis, oral trauma and reproductive disease. 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.