Mexican west-coast rattlesnake — Fact Sheet

Crotalus basiliscus · Mexican west-coast rattlesnake

📋 At a glance


Adult size	120-200 cm
Lifespan	Approximately 18-25 years
Taxonomy	Monotypic species in the C. molossus complex
Origin	Pacific slope and adjacent uplands of western Mexico
Activity	Crepuscular; terrestrial and low-climbing
Difficulty	Expert institutional display animal
Legal	CITES: not listed; EU: Annex D; endemic to Mexico and NOM-059 `Pr`; local law applies

🏠 Enclosure

Minimum adult space: 200 x 100 x 100 cm; larger individuals need more.
Use a locked secondary room, two full-size lockable shifts, protected service access and clear inspection lanes.
Bolt low shelves/branches and support heavy décor from the base. Eliminate falls, crush points and blind servicing areas.
Never free-handle. Two trained adults with assigned roles attend every primary opening.

💡 Lighting and 🌡️ temperature

Bright visible light for 11-13 hours; optional measured Ferguson Zone 1 UVB with full shade.
Basking surface: 32-35°C
Ambient: 25-30°C
Cool retreat: 22-25°C
Night: 20-24°C
Do not apply generic brumation to animals without precise locality.

💧 Humidity and water

Ambient 45-65% with ventilation; local shedding retreat 60-75% and modest provenance-led wet-season change.
Keep surfaces able to dry; provide a heavy bowl of clean water through protected access.

🐁 Feeding

Moderate frozen-thawed whole prey every 14-28 days, adjusted to size, season and body condition.
Avoid power feeding and live rodents. Lock the snake away before retrieving refused prey.

🩺 Health and emergency warnings

Watch for obesity, respiratory signs, retained shed, mites, oral disease, burns, abrasions and weak décor.
A bite from any age is a hospital emergency. Call emergency services/poison control, keep still and remove constricting items.
No tourniquet, cutting, suction, ice, shock, massage or home antivenom. Keep rehearsed bite and escape plans.