Southern Pacific Rattlesnake — Fact Sheet

Crotalus helleri · Southern Pacific Rattlesnake

📋 At a glance

🏠 Enclosure

• Indoor locked enclosure inside secondary room containment.
• Minimum 180 x 90 x 90 cm for one adult; house singly.
• Full-body positively lockable shift, two-step locks and neonate-proof gaps.
• 8-12 cm compactable mineral soil/sand; disposable substrate during at least 90 days quarantine.
• Avoid unstable rocks, sharp wire, aromatic wood and deep uninspectable clutter.
• Protected contact only; two trained adults and communications at every opening.

🪨 Enclosure furniture

• Snug warm and cool refuges plus ventilated humid shed hide.
• Anchored rock-textured shelf or cork and low visual cover.
• Clear inspection lane, protected feeding/service port and stable water bowl.
• Lamp cages and wiring outside primary containment or behind locked guards.

💡 Lighting

• UVB recommended, not mandatory: measured Ferguson Zone 2 over part of the warm zone.
• Linear UVB plus bright white visible light; retain complete shade.
• Replace lamps by manufacturer guidance and verify with a meter.
• 10-14 hours seasonally; full darkness at night.

🌡️ Temperature

• Basking spot: 30-33 °C

• Warm zone: 23-28 °C

• Cool zone: 19-23 °C

• Night: 15-21 °C

• Coastal, inland and montane lines need different seasonal timing.

• Measure air and surface; thermostat, guard and independently alarm heat.

• Never use unguarded heat rocks or remove the cool retreat.

💧 Humidity & water

• Ambient 40-60%; 60-75% in one ventilated shed refuge.
• Fresh water permanently through protected access.
• Avoid permanent dampness and condensation, even for coastal provenance.
• Persistent soaking or poor shed → review heat, mites, hydration and disease.

🐁 Diet

Feed freely:

• Appropriately sized frozen-thawed mice; juveniles every 7-14 days.

In moderation:

• Small rats for large adults every 14-28 days, based on weight and condition.

Avoid:

• Live rodents, oversized meals, frequent feeding and loose feeding tubs.

Supplements:

• None routinely with complete whole vertebrate prey.

💤 Brumation

• Only healthy, established, documented adults in a managed breeding programme.
• After fasting and gut clearance, cool gradually to 8-14 °C under professional review.
• Never cool juveniles, new arrivals, gravid, thin, dehydrated or ill snakes.
• Do not apply a mountain programme automatically to lowland Baja stock.

🩺 Health — warning signs

• Persistent cool-hide use or restless escape behaviour → overheating.
• Thick body and poor muscle definition → obesity.
• Incomplete shed or concentrated urates → dehydration or illness.
• Bubbles, wheeze or open-mouth breathing → respiratory disease.
• Oral lesions, mites or abnormal faeces → stomatitis or parasites.
• Burn/crush injury → inadequate heat guard or unstable décor.

Secure behind the shift and use an experienced reptile veterinarian; envenomation requires immediate hospital care and no home treatment.