Spider-tailed Horned Viper

🔤 Taxonomy

Pseudocerastes urarachnoides was described in 2006 and remains an accepted species. Its modified tail is a prey lure, not an attached arthropod. Keep its identity separate from P. persicus and P. fieldi, whose venom biology differs markedly.

📌 Description

An approximately 50-80 cm, rough-scaled ambush viper with an enlarged tail tip surrounded by elongated scales. Tail damage compromises a specialized feeding structure. Secure rocky cover and unobstructed lure movement matter more than an elaborate sand display. Captive longevity remains uncertain; speculative multi-decade estimates should not be presented as established.

The active-season values below are provisional management starting points, not demonstrated physiological optima or safety limits. Enclosure dimensions are practical recommendations for one adult; increase them for a larger individual. Confirm the plan with an experienced reptile veterinarian and retain locality records.

📋 Quick reference

Care point	Provisional active-season target
Adult length	50-80 cm
Enclosure, one adult	120 × 70 × 70 cm
Ambient air	24-28°C
Basking surface	32-35°C
Cool retreat	21-24°C
Night air	18-22°C
Relative humidity	30-50%
Adult meals	14-21 days

☠️ Venom

Experimental studies show strong procoagulant and cell-damaging activity, substantially different from the neurotoxic profile of P. fieldi. Human outcomes are poorly documented; potentially serious bleeding, clotting disturbance and tissue injury must be anticipated. No species-specific antivenom was identified in the reviewed BfN report, and cross-neutralization cannot be assumed.

Treat every bite as an emergency, including an apparently dry bite. Move away, call emergency services, keep the person still, remove rings and support the limb without compression. Do not cut, suck, ice or tourniquet the wound, and do not catch the snake. Follow poison-centre instructions. Agree a receiving hospital and antivenom access before acquisition; treatment belongs in hospital.

🌍 Distribution

Western Iran, including Ilam, Kermanshah and Khuzestan, and adjacent eastern Iraq. Records include rocky Zagros foothills and gypsum-rich terrain. Iran-only accounts predate the Iraqi records. The Mehran-area climate point illustrates regional seasonality, not a known occupied crevice.

Native-range context; shaded countries do not imply continuous occupation

🌡 Climate across the native range

Regional outdoor normals show seasonality, not enclosure settings. These representative settlement coordinates are not exact snake localities.

Mehran region — Iran

View location on Google Maps

Month	Min °C	Mean °C	Max °C	RH %
January	5.5	10.1	14.9	67
February	6.4	11.8	17	62
March	10.5	16.8	22.5	48
April	15.9	23.2	29.2	37
May	22	30.1	36.3	22
June	27.2	35.3	41.7	14
July	30	37.7	44	14
August	29.7	37.5	44	14
September	25.4	33.1	40	16
October	20	26.8	33.2	26
November	12.2	17.4	22.8	51
December	7.4	12	16.9	65

Weather data by Open-Meteo.com · CC BY 4.0 · Monthly normals calculated by Herpeton Academy from daily archive values.

⚖️ Legal status

CITES Appendix II and EU Annex B. International trade requires the appropriate export or re-export documents and, for EU entry, the required import permit. Retain evidence of lawful parental stock and captive-breeding history; an invoice saying “captive bred” alone is not enough.

The Bern Convention is not the principal trade framework for this wholly Asian native range; do not infer exemption from national protection.

Legal review: 17 September 2026. National capture, possession, registration, breeding, sale and transport rules may be stricter. Verify permits before transfer and keep invoices, breeder identity, parentage and import records. Trade status does not itself authorize keeping a venomous snake.

🤌 Husbandry

Keep Pseudocerastes urarachnoides individually in a locked enclosure within an access-controlled venomous-reptile room. Secondary containment and a lockable shift compartment should permit water changes and cleaning only after the animal has been isolated and visually accounted for. Free-handling is unacceptable. Prepare written bite and escape plans, trained backup cover and a veterinary arrangement before acquisition.

Quarantine for at least 90 days as a working minimum, longer when the veterinarian advises. Use separate tools and a simple enclosure; record feeding, sheds, faeces and body condition. Arrange parasite screening for uncertain-origin animals or abnormal stools. Weigh only through an established protected-contact procedure.

💡 Lighting

Provide about 12-14 hours of visible light during the active season, with darkness at night and shaded retreats. A species-specific UVB requirement has not been demonstrated. If low-level UVB is used, measure exposure and retain complete shade; do not infer lamp strength from desert photographs. Guard lamps and wiring against contact.

🌡 Heating and temperature

Begin with air at 24-28°C, a local basking surface at 32-35°C, a cool retreat at 21-24°C and night air at 18-22°C. These are cautious working bands, not tolerance limits. Measure air, surface and cool-hide temperatures separately. Thermostat-control heating; check the room during summer because a thermostat cannot cool hot air.

Seasonal cooling requires a documented, locality-specific plan for healthy, established adults. Do not cool new arrivals, thin, sick or gravid animals, or copy an adult breeding cycle onto juveniles. Outdoor monthly normals are not brumation instructions.

💧 Humidity and water

Use 30-50% relative humidity as an initial management band, with ventilation and a mostly dry resting surface. Provide a small locally moist retreat during shedding without wetting the whole enclosure. Offer clean drinking water continuously in a stable, shallow bowl, serviced through the protected system. Dry habitat does not mean absence of water. Persistent condensation or repeated retained sheds needs review; never peel skin or force soaking.

🌿 Enclosure and decoration

Use at least the practical 120 × 70 × 70 cm layout in the table and allow the snake to stretch fully. Check door gaps, vents and cable holes against the smallest animal housed. Fix rocks directly to the enclosure base so excavation cannot undermine them; retain clear sightlines to shift doors. Avoid sharp gravel, aromatic wood and unstable piles. Remove waste after securing the snake.

Use about 5-8 cm of compacted sandy soil with fixed smooth stones and low branches, leaving room for the tail lure. Avoid narrow abrasive gaps that can trap the tail. Paper facilitates quarantine; a moist retreat supports shedding without wetting the entire rocky layout.

🐁 Feeding

Bird-luring behaviour is documented, but the BfN husbandry review reports acceptance of mice and chicks. Verify the individual’s reliable diet before acquisition. Offer appropriately sized thawed whole prey, no wider than the body; do not use wild birds. Juvenile feeding refusal needs professional assessment, not amateur force-feeding.

The table gives an initial adult feeding interval of 14-21 days; adjust portions and timing to weight trend and condition. Deliver food through the collection’s protected feeding system. Avoid live rodents and substrate-coated food; dehydration, low temperatures and oversized meals increase regurgitation and impaction concerns. Whole prey normally needs no routine calcium or vitamin dusting. Do not improvise supplementation or force-feeding.

🥚 Breeding

The BfN review reports reproductive maturity around four years and 70 cm, clutches of 8-10 eggs, and hatching after about 50 days at 30°C. These are reported breeding outcomes, not guaranteed targets for every line. Confirm sex professionally and provide a moist laying retreat. Seasonal cycling and neonatal containment must be planned before any introduction.

Breeding adds exposure risk. Prepare separate, escape-proof neonatal housing before pairing, avoid permanent cohabitation, and retain parentage, dates, meals and transfer records. Only breed when lawful placements and competent staff are available.

🩺 Common problems

Overheating: repeated escape attempts or unusual exposed resting require immediate measurement of the cool retreat.
Dysecdysis and dehydration: review drinking access and the moist refuge; repeated problems need veterinary assessment.
Respiratory infection or stomatitis: wheezing, bubbles or oral discharge require prompt professional care.
Dermatitis, impaction, obesity and parasites: dirty wet bedding, substrate ingestion, excessive feeding or persistent weight loss need correction and diagnosis. Do not use automatic deworming or home restraint.

📌 Conclusion

The spider-tailed viper belongs only in a collection able to protect the tail, verify Annex B provenance and support difficult neonates. Documented captive reproduction does not resolve the limited clinical knowledge of its venom.

📚 Sources and further reading

ReptiFiles was checked first on 17 September 2026; no species-specific guide was found. Numerical recommendations are separated from directly reported breeding outcomes. Historical care reports are not current medical instructions.