Giant horned lizard (Phrynosoma asio)
Iguanas · Difficulty: Beginner with some knowledge
Key facts and care guidance for Giant horned lizard (Phrynosoma asio) (origin: South-western Mexico). Adult size around 12–18 cm. Life expectancy 5–10 years. The values below are carefully researched guidance.
Short answers
Giant horned lizard: How big does the enclosure need to be?
120×60×60 cm for a group.
Giant horned lizard: What temperature does it need?
Daytime 27–33 °C, basking spot Basking spot 42–48 °C, at night 15–20 °C.
Giant horned lizard: Does it need UVB lighting?
UVB: Essential (UVB 10.0–12.0).
Giant horned lizard: How long do they live?
Life expectancy: 5–10 years.
Giant horned lizard: Is it suitable for beginners?
Partly – manageable with some prior knowledge (difficulty: Beginner with some knowledge).
Climate
- Daytime temperature
- 27–33 °C
- Night temperature
- 15–20 °C
- Basking spot
- Basking spot 42–48 °C
- Humidity
- 30–50 %
- UVB
- Essential (UVB 10.0–12.0)
Enclosure
- Minimum size
- 120×60×60 cm for a group
- Substrate
- A sand-loam mix they can dig in, with stone slabs, roots and a few twigs
Feeding
- Food
- Crickets, house crickets, roaches and locusts, dusted regularly with calcium and vitamins
- Feeding interval
- adults 3×/week
Key facts
- Adult size
- 12–18 cm
- Life expectancy
- 5–10 years
- Origin
- South-western Mexico
- Protection status
- Not listed under CITES
- Brumation
- A cooler rest of 8–12 weeks at 10–15 °C
- Cohabitation
- Keeping them singly is least stressful. Horned lizards are sedentary loners; for this rare species there is barely any research on male fighting. For breeding, put one male with one or two females temporarily and separate them again at signs of stress.
Notes
The largest species in the genus. Here too: without ants there is no keeping it long term.
Do you keep this species?
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Related species
- Mountain horned lizard (Phrynosoma orbiculare) – Expert
- Regal horned lizard (Phrynosoma solare) – Beginner with some knowledge
- Greater short-horned lizard (Phrynosoma hernandesi) – Beginner with some knowledge
- Coast horned lizard (Phrynosoma coronatum) – Beginner with some knowledge
- Round-tailed horned lizard (Phrynosoma modestum) – Beginner with some knowledge
- Texas horned lizard (Phrynosoma cornutum) – Expert
- Desert horned lizard (Phrynosoma platyrhinos) – Beginner with some knowledge
- Aliniger anole (Anolis aliniger) – Beginner with some knowledge
What you need to start
To keep Giant horned lizard (Phrynosoma asio) you typically need: a suitable enclosure (120×60×60 cm for a group), substrate (A sand-loam mix they can dig in, with stone slabs, roots and a few twigs), a heat source with a thermostat, UVB lighting, thermometer and hygrometer, a water dish and hides. You will find equipment in the Reptoria marketplace.
The complete, interactive care database is in the Reptoria app.
Last updated: 5 November 2026 · Editor: Reptoria editorial team · Sources include: https://en.wikipedia.org/wiki/Giant_horned_lizard, https://reptile-database.reptarium.cz/species?genus=Phrynosoma&species=asio, Reptile Database Phrynosoma asio (Raya-García 2014, Herpetological Review 45: 330, „crepuscular and nocturnal activity“ als Einzelbeobachtung); Afsar et al. 2018, Ecologica Montenegrina 19 (führt P. asio unter nächtlichen Beobachtungen bei überwiegend tagaktiven Echsen). Haltungsfelder (Sonnenplatz 42–48 °C, UVB zwingend) waren schon tagaktiv
All values are non-binding guidance and do not replace expert advice. Research thoroughly from several sources before acquiring and keeping an animal, and observe the applicable law (species and animal protection in particular).