🐾 LandCare difficulty: IntermediateLegal complexity: Medium
Mexican red-knee tarantula
Brachypelma hamorii · also called Mexican red-knee tarantula, red knee, Mexican redknee, true red-knee
Mexican red-knee tarantulas are slow-moving, docile New World tarantulas long popular in the U.S. pet trade. They are CITES Appendix II — captive-bred individuals are legal but international and interstate movement is documented.
Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.
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Quick facts
| Size | Adult leg span 5–6 inches; females larger and longer-lived than males. |
| Lifespan | 15–25 years |
| Social needs | solo |
| Native region | Western Mexico (Pacific coast) |
| Origin | New World |
| Climate | ⛅ Subtropical |
| Family | Theraphosidae |
| Genus | Brachypelma |
Part of the Tarantulas
Theraphosid spiders kept as low-maintenance display invertebrates. New World species are generally docile with mild venom but bear irritating urticating hairs, while Old World species lack those hairs but tend to be fast, defensive, and have more potent (though rarely life-threatening) venom.
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Habitat & space requirements
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Habitat & enclosure
The Mexican red knee is a terrestrial, burrowing tarantula best kept in a single-occupant terrarium that prioritizes floor space over height — a tall enclosure invites dangerous climbing falls. A widely used rule of thumb is an enclosure several times the spider's leg span in each horizontal dimension, with low height. Provide a deep layer of substrate such as coconut fiber, peat, or a soil mix so the spider can burrow and feel secure, plus a hide and a shallow water dish.
This is an arid-to-semi-arid species from Mexico, so humidity needs are modest; most keepers maintain a fairly dry enclosure with a water dish, lightly raising moisture (for example during a molt) rather than keeping it damp. Overly wet conditions are a common husbandry mistake that can cause health problems. Room-temperature ranges typical of a home are generally suitable; avoid extremes.
Security and stability matter more than gadgets: a snug-fitting, well-ventilated lid (tarantulas can escape and climb), a stable substrate for burrowing, and minimal disturbance produce a calm, healthy spider. Tarantulas are display-and-observe animals, not interactive ones.
Substrate
Use 3-5 inches of slightly moist coconut fiber, peat, or topsoil that supports occasional burrowing while staying mostly on the drier side. Keep one area lightly damp and let the rest dry, reflecting their semi-arid scrubland origins.
Equipment & setup
A 5-10 gallon terrestrial enclosure at 75-82F works well, with room heat sufficient and no UVB required; a side-mounted thermostatted mat can be used only in cold rooms. Provide a cork-bark hide and a filled shallow water dish, avoiding under-tank heaters directly below the animal.
Diet
Mexican red knee tarantulas are insectivores fed appropriately sized live feeder insects such as crickets, dubia roaches, and similar, with prey generally no larger than is sensible for the spider's size. Feeding frequency varies widely by age and individual; spiderlings eat more often, while adults of this slow-growing species often eat sparingly and may fast for extended periods, which is normal.
Provide a shallow water dish with fresh water; tarantulas drink. Remove uneaten prey, especially before and during molts, because feeder insects can stress or even injure a vulnerable molting spider. A tarantula in premolt (often darker, sluggish, and refusing food) should simply be left alone and not fed until well after the molt hardens.
The common mistakes are overfeeding, leaving live prey in with a non-feeding or molting spider, and worrying unnecessarily about a healthy adult's long fasts. When in doubt about prolonged refusal with other signs of illness, an invertebrate-experienced or exotic veterinarian can advise.
Behavior & temperament
The Mexican red knee is prized for a famously docile, calm temperament, which is a major reason it is recommended as a beginner-friendly tarantula. It tends to move slowly and, when disturbed, is more likely to retreat to its burrow than to act defensively, though individuals vary and young spiders can be skittish.
Like other New World tarantulas, it defends itself primarily with urticating hairs — fine barbed hairs it can kick off the abdomen that irritate skin and are especially hazardous to eyes and airways — rather than relying on a significant bite. Handling is generally discouraged: it stresses the spider, risks a fatal fall from even a short height, and exposes the keeper to urticating hairs. This is an animal to watch, not to cuddle.
A bite is possible if the spider is cornered or mishandled; for this species the venom is considered mild (comparable for most people to a bee sting), but allergic reactions and the mechanical injury of fangs are reasons enough to avoid provoking one. Calm, hands-off keeping suits both spider and owner.
Health
Tarantulas are remarkably long-lived: females of this species can live for decades (often cited around 25 to 30 years), while males live far shorter lives, typically only several years and usually dying not long after maturing. Adopting one — especially a female — is genuinely a long-term commitment.
Most health problems are husbandry-related. Overly wet enclosures, falls from height (a ruptured abdomen from a fall is frequently fatal), retained or problematic molts, and dehydration are the main concerns. Molting is a vulnerable time: a spider on its back is molting, not dying, and must be left completely undisturbed and unfed until its new exoskeleton hardens. Parasites and fungal issues can occur, often tied to poor conditions.
Preventive themes are appropriate (generally dry) humidity with a water dish, deep secure substrate, low enclosure height to prevent falls, minimal handling, and patience around molts and natural fasting. Specialized invertebrate veterinary care exists but is uncommon; an exotic veterinarian can advise where illness is suspected. This entry is general guidance only.
Tips, DIY & hacks
This iconic, long-lived and docile species is an excellent beginner display tarantula but is a slow grower, so be patient. They readily kick urticating hairs when stressed, so minimize handling and disturbance, and a half-buried cork tube gives them the secure retreat they favor.
Origin & history
The Mexican red knee tarantula (Brachypelma hamorii) is native to the Pacific-facing scrublands and forests of western Mexico. Long one of the most iconic tarantulas in the world — its striking black body with orange-red leg 'knees' made it a film and pop-culture staple — it became enormously popular in the pet trade.
That popularity, plus habitat pressures, led to conservation concern, and Brachypelma tarantulas are protected under CITES, with trade regulated to curb unsustainable wild collection; captive breeding now supplies most hobby animals. Taxonomic revisions split the classic 'Brachypelma smithi' of older literature, so the animal long sold under that name is, for many specimens, properly B. hamorii — a frequent source of naming confusion in care guides.
Anecdotes & owner lore
Community experience and cultural notes — not veterinary advice. Every animal is an individual; treat these as colour, not care instructions.
If you've ever seen a 'scary' tarantula in a movie, there's a good chance it was a Mexican red knee — its bold orange-and-black coloring and unflappable, slow-moving temperament made it the go-to 'actor' for films and photo shoots, including memorable appearances in classic spy and adventure movies. Ironically, the spider Hollywood cast as a menace is one of the gentlest in the hobby.
Keepers are endlessly charmed by tarantula quirks: the dramatic, motionless molt (every new owner's first heart-stopping moment, convinced their pet has died, before it emerges glossy and brand-new), the way these spiders 'redecorate' by webbing and moving substrate, and the long, contemplative fasts that can last weeks. The species' decades-long lifespan means a red knee acquired in childhood can still be around in adulthood, and hobbyists speak of individual spiders with real affection despite never laying a (safe) finger on them.
Common ailments
- Dehydration — common
- Fall injury (abdominal rupture) — common — A leading husbandry-related cause of death in terrestrial tarantulas; keep enclosure height low and avoid handling.
- Molting complications — common
Legality (US)
Educational only. Confirm current rules with your state wildlife agency or local authority before acquiring an animal.
- US — Regulated — Brachypelma hamorii is on CITES Appendix II — international commercial trade requires permits. U.S. captive-bred individuals are legal to own and trade domestically.
Reviewed and signed off by: KinStation Editorial - pre-launch draft (pending DVM review)
Sources
- Brachypelma hamorii (Mexican redknee tarantula) — Wikipedia (wiki)
- Brachypelma hamorii care sheet — The Tarantula Collective (care guide)
- Mexican Red Knee Tarantula Caresheet — The Bio Dude (care guide)
- Cover image — Wikimedia Commons — Brachypelma hamorii (Mexican red-knee tarantula; file under former name B. smithi), via en.wikipedia.org/wiki/Brachypelma_hamorii (wiki)