Red Knee Tarantula
Species Description

The Mexican Red Knee Tarantula (Brachypelma hamorii) stands as the most iconic and recognizable tarantula species worldwide. For decades, this stunning spider has served as the ambassador species for tarantula keeping, introducing countless enthusiasts to the hobby through its striking appearance, docile nature, and frequent appearances in movies and media.

The taxonomic history of this species includes significant recent revision. For many years, the pet trade Mexican Red Knee was identified as Brachypelma smithi. However, detailed research in 2017 revealed that the tarantulas commonly kept in the hobby are actually B. hamorii, while B. smithi represents a separate, less common species from a different region of Mexico. This distinction matters primarily for scientific accuracy and breeding programs.

Common names include Mexican Red Knee, Red Knee Tarantula, Mexican Redknee, and occasionally Orange Knee Tarantula. The name references the distinctive bright orange-red coloration on the leg joints (patellae), which creates the species' characteristic banded appearance. Some keepers simply call them Red Knees or by the scientific abbreviation B. hamorii.

The genus Brachypelma contains numerous Mexican tarantula species, many sharing similar care requirements and beginner-friendly temperaments. Close relatives include the Mexican Redleg (B. emilia), Mexican Fireleg (B. boehmei), and Curly Hair Tarantula (Tliltocatl albopilosus, formerly Brachypelma). Beginning keepers sometimes confuse these related species, though each has distinguishing characteristics. All Brachypelma species face collection pressure and legal protection, making captive-bred specimens essential.

The Mexican Red Knee Tarantula presents one of the most visually striking appearances in the tarantula world. Adults reach a legspan of 5-6 inches, with robust, stocky bodies characteristic of terrestrial Brachypelma species. Their substantial build and bold coloration make them impressive display animals.

The base coloration consists of deep black to dark brown covering the carapace, abdomen, and leg segments. This dark background provides dramatic contrast for the species' namesake feature—brilliant orange to red-orange bands at the patellae (knee joints) of each leg. Additional orange coloration appears at the junction of other leg segments, creating an overall banded appearance. The carapace often displays a lighter tan to peachy border around the edges.

The abdomen is covered in dark setae (hairs) with a velvety black appearance. Like all New World tarantulas, Mexican Red Knees possess urticating hairs on their abdomen—specialized defensive bristles that can be kicked at threats. These microscopic barbed hairs cause irritation to skin and mucous membranes but pose no serious danger to humans.

Sexual dimorphism becomes apparent at maturity. Males develop distinctly different coloration, often appearing more muted with tan or brownish tones replacing the deep black of females. Mature males also develop tibial hooks on their front legs—small clasping structures used during mating—and emboli (reproductive structures) on their pedipalps. Males have noticeably longer legs relative to body size and slimmer builds overall.

Females maintain the bold coloration throughout their lives, becoming more vibrant with each successive molt. They possess stockier builds with larger abdomens, particularly when well-fed or carrying eggs. Size differences become substantial, with adult females significantly outmassing males of the same legspan.

Juvenile Mexican Red Knees appear as miniature versions of adults but with less intense coloration. The characteristic red-orange bands develop gradually through successive molts. Very young spiderlings may show only hints of the adult pattern, with colors becoming progressively more vivid as they grow. Full adult coloration develops over several years of maturation.

Mexican Red Knee Tarantulas have earned their reputation as the quintessential beginner tarantula through consistently docile, predictable behavior. Among the many tarantula species available, few match the calm temperament that has made this species famous. Their easygoing nature allows handling that would stress or provoke defensive responses in most other tarantula species.

The typical Mexican Red Knee displays remarkable tolerance for disturbance. When approached, they often remain motionless rather than fleeing or displaying defensive postures. Even during cage maintenance or rehousing, most individuals move slowly and deliberately rather than bolting or striking. This predictability makes them comfortable to work with, particularly for newcomers to tarantula keeping.

Defensive behaviors, when displayed, typically involve threat postures—raising the front legs and exposing the fangs—rather than actual aggression. Most Mexican Red Knees will exhaust these warning displays before considering a bite. Their primary defense against persistent threats involves kicking urticating hairs from their abdomen, creating a cloud of irritating bristles. This defense is unpleasant but not dangerous, causing skin irritation and potentially eye or respiratory irritation if contacted.

Bites from Mexican Red Knees are exceptionally rare in captive situations. Their venom, while effective against prey, produces only mild effects in humans comparable to a bee sting. No serious medical consequences have been documented, though individual reactions vary. The species' extreme reluctance to bite makes envenomation a minimal concern for most keepers.

Activity patterns follow a primarily nocturnal schedule. During daylight hours, Mexican Red Knees typically remain hidden in burrows or retreats. As evening approaches, they often position themselves at burrow entrances, waiting for prey. Night brings the most activity, with hunting, exploration, and occasionally wandering if hungry. In captivity, they may adapt to some daytime activity, particularly at feeding times.

The species earns the affectionate nickname pet rock from experienced keepers due to extended periods of complete inactivity. Hours or even days may pass with no visible movement. This sedentary lifestyle represents normal, healthy behavior rather than a problem. Activity increases around feeding and after molting, with females particularly active when searching for mates during breeding season.

Stress indicators include excessive hiding, refusal to eat for extended periods outside normal pre-molt fasting, constant pacing, and repeated threat displays. Well-adjusted Mexican Red Knees eventually adopt favorite positions in their enclosure, often returning to the same spot consistently.

Housing a Mexican Red Knee Tarantula requires understanding their terrestrial, burrowing nature. Unlike arboreal species, these tarantulas need horizontal space rather than climbing room. A 10-gallon aquarium or specialized terrestrial tarantula enclosure measuring approximately 12x12x12 inches provides adequate space for adults. Larger enclosures are acceptable but unnecessary—tarantulas do not require extensive territory.

Enclosure height deserves careful consideration. Mexican Red Knees cannot fly or jump safely from heights, and falls present serious injury risk. Their heavy bodies and relatively fragile abdomens rupture easily upon impact with hard surfaces. Maximum height should limit potential falls to 1.5-2 times the tarantula's legspan. Filling excess vertical space with deep substrate accomplishes this while providing burrowing opportunity.

Substrate selection is critical for this burrowing species. Coconut fiber, peat moss, or a mixture with topsoil works excellently. Depth should reach 4-6 inches minimum, allowing the tarantula to excavate to its preference. Some individuals dig extensive burrows while others merely create shallow scrapes. Maintain the lower substrate layers slightly moist while keeping the surface dry to prevent issues while providing humidity gradients.

Temperature requirements fall within a comfortable range of 70-85°F, with the species tolerating normal room temperature in most homes without supplemental heating. If heating is necessary, under-tank heat pads placed on one side create a thermal gradient. Never position heat sources directly above the enclosure or use heat rocks, which can cause burns. Temperature stability matters more than achieving specific numbers.

Humidity should remain moderate at 60-70%, easily maintained through substrate moisture and a water dish. Misting is rarely necessary and can create overly damp conditions that promote bacterial and fungal growth. The water dish serves as the primary humidity source while providing drinking water. Ensure the dish is shallow enough to prevent drowning—tarantulas can drown in just a few centimeters of water.

Hide provision is essential for reducing stress. Cork bark, half-buried flower pots, or commercial reptile hides work well. Position hides to allow the tarantula to feel secure while remaining somewhat visible for observation. Many keepers provide one hide near the warm side and one on the cooler side, allowing thermoregulation while remaining hidden.

Ventilation requirements are moderate but important. Stagnant, overly humid air promotes mold and respiratory issues. Enclosures should have adequate airflow through screened lids or ventilation holes without creating drafts. Cross-ventilation—holes on opposite sides—provides better airflow than top-only ventilation.

Secure lids are absolutely essential. Tarantulas are skilled escape artists, and even small gaps may allow passage. Ensure all screen lids fit tightly and any ventilation holes are too small for the tarantula to squeeze through. Lost tarantulas face dehydration and injury risks in household environments.

Maintenance involves removing uneaten prey within 24 hours, spot-cleaning waste, and changing water regularly. Full substrate changes are needed only every 6-12 months unless contamination occurs. Never use pesticides, scented products, or chemicals near tarantula enclosures.

Mexican Red Knee Tarantulas are opportunistic insectivores that readily accept a variety of prey items in captivity. Their enthusiastic feeding response and willingness to eat make them among the easiest tarantulas to feed. In the wild, they consume whatever appropriately-sized invertebrates wander near their burrow entrances.

The staple captive diet consists of commercially raised feeder insects. Crickets represent the most common and readily available option, providing good nutrition and appropriate size ranges. Dubia roaches offer excellent nutrition with less odor and noise than crickets. Other suitable prey includes mealworms, superworms, hornworms, and occasional waxworms as treats. Variety benefits nutritional completeness.

Prey size should approximate the tarantula's body length—roughly the distance from chelicerae to spinnerets—or slightly smaller. Oversized prey may injure the tarantula, particularly during vulnerable post-molt periods. Undersized prey is safe but requires offering multiple items to satisfy nutritional needs. Err toward smaller rather than larger when uncertain.

Feeding frequency varies with age and size. Spiderlings and juveniles require more frequent feeding to support rapid growth—every 3-5 days works well for young specimens. Sub-adults can be fed weekly, while adults may only require feeding every 1-2 weeks. Watch the abdomen size as a guide: a healthy tarantula maintains a plump but not overly distended abdomen roughly the size of the carapace.

Pre-killed prey is acceptable and sometimes preferable. Crushing the head of feeder insects before offering eliminates any risk of prey injuring the tarantula. This approach is particularly advisable during post-molt periods when the tarantula's exoskeleton remains soft. Some keepers exclusively use pre-killed prey without issues.

Gut-loading feeder insects significantly improves nutritional value. Feed crickets and roaches nutritious foods—vegetables, fruits, and commercial gut-load products—for 24-48 hours before offering them to your tarantula. The nutrients in the prey's gut transfer to the tarantula, providing vitamins and minerals not present in the insects themselves.

Fasting periods are normal and should not cause alarm. Mexican Red Knees commonly fast for extended periods before molting, sometimes refusing food for weeks or even months. Adult females may fast for 2-3 months pre-molt without concern. Never force feed or leave live prey with a fasting tarantula—remove uneaten insects after 24 hours.

Water provision is essential despite their desert-adjacent origins. A shallow water dish should always be available and refreshed every few days. Tarantulas drink by pressing their chelicerae into the water surface. Some keepers observe their tarantulas submerging part of the body during drinking. The water dish also contributes to enclosure humidity.

Avoid wild-caught insects, which may carry parasites or pesticide residues. Never feed fireflies, which are toxic to tarantulas. Vertebrate prey like pinky mice is unnecessary and potentially dangerous—the nutritional value does not justify the risks of injury from struggling prey or obesity from fatty foods.

Mexican Red Knee Tarantulas rank among the longest-lived invertebrates kept as pets, with female lifespans reaching 25-30 years under optimal care. Males live significantly shorter lives, typically 5-10 years, dying within months to a year or two after maturing. This dramatic lifespan difference between sexes means that female Mexican Red Knees represent multi-decade commitments comparable to dogs or cats. Healthy specimens display plump abdomens, responsive behavior, good feeding response outside of fasting periods, and intact, glossy exoskeletons. Veterinary care for tarantulas is extremely limited, with few practitioners experienced in arachnid medicine. Prevention through proper husbandry remains the only practical health management approach.

With proper care, Mexican Red Knee Tarantulas provide decades of fascinating observation and rewarding keeping. Their hardiness and tolerance for minor husbandry inconsistencies make serious health problems uncommon when basic needs are met. The keys to success include maintaining consistent moderate humidity, providing clean conditions, ensuring water access, and never disturbing molting individuals. When questions arise, experienced tarantula keeping communities provide excellent support. These long-lived animals reward patient keepers with impressive longevity and the privilege of observing natural behaviors rarely seen in more demanding pets.

Mexican Red Knee Tarantulas rank among the most handleable tarantula species, though handling should still be approached with care and respect for the animal's nature. Their calm temperament and predictable behavior have made them handling favorites, but understanding proper techniques and limitations remains essential for the safety of both keeper and tarantula.

The fundamental handling technique involves allowing the tarantula to walk onto a flat hand rather than grabbing or lifting. Approach slowly from the front where the tarantula can see you. Gently guide the spider forward with a soft brush or your other hand. Let it walk onto your palm at its own pace. Cup your hands loosely, allowing the tarantula to move freely while preventing falls.

Handling sessions should be brief—5-10 minutes maximum—and conducted close to the ground or over a soft surface. The greatest risk during handling is falling. A Mexican Red Knee falling even a short distance onto a hard floor can suffer fatal abdominal rupture. Always handle while seated with the tarantula close to your lap or a padded surface. Never walk around while holding a tarantula.

Urticating hairs represent the primary defensive mechanism of New World tarantulas including Mexican Red Knees. When stressed, they kick these barbed bristles from their abdomen with their hind legs. Contact with skin causes itching and irritation; contact with eyes or respiratory passages is more serious. Wash hands after handling and avoid touching your face. If hair-kicking occurs, gently return the tarantula to its enclosure—it is communicating that handling should end.

Certain situations require avoiding handling entirely. Pre-molt tarantulas—identifiable by darkened coloration, refusal to eat, and lethargy—should never be handled. Post-molt specimens need 1-2 weeks for their exoskeleton to fully harden before handling is safe. After feeding, wait at least 24 hours before handling to prevent regurgitation. Defensive individuals displaying threat postures are clearly communicating they do not want to be handled.

The molting process itself requires special care regardless of handling. When a tarantula flips onto its back, it is beginning to molt—not dying. Never disturb or right a molting tarantula. The process can take hours, and any disturbance can cause fatal complications. Increase humidity in the enclosure and ensure no live prey remains. After molting, the tarantula will right itself when ready. Post-molt individuals appear pale and soft, darkening and hardening over several days to weeks.

Many experienced keepers limit or avoid handling entirely, preferring observation. Mexican Red Knees do not benefit from or enjoy handling—they merely tolerate it. Stress from frequent handling can shorten lifespan and trigger defensive hair-kicking that leaves bald patches. The choice to handle should prioritize the tarantula's wellbeing over the keeper's desire for interaction.

Mexican Red Knee Tarantulas represent an ideal first tarantula for committed keepers willing to research proper care. Their hardiness, docile nature, and tolerance for beginner mistakes have earned them their reputation as the quintessential starter species. However, potential keepers should understand what tarantula ownership actually entails before acquiring these impressive animals.

Time commitment is minimal once the enclosure is established. Daily responsibilities include checking water and observing the spider's condition—perhaps 5 minutes total. Feeding occurs only weekly or biweekly. Enclosure maintenance requires occasional spot-cleaning and periodic substrate changes. Those seeking interactive, high-engagement pets should look elsewhere, but those appreciating quiet observation will find these spiders rewarding.

Financial investment varies considerably. Captive-bred spiderlings cost $50-100, while larger juveniles and adults command $100-300 or more depending on size and sex. Females cost significantly more due to their dramatically longer lifespans. Initial enclosure setup runs $50-150 for quality housing, substrate, hides, and accessories. Ongoing costs are minimal—feeder insects represent the primary recurring expense.

The multi-decade lifespan of female Mexican Red Knees demands serious consideration. A female acquired as a spiderling may live 25-30 years—longer than many dogs or cats. This commitment requires planning for the animal's care through life changes, moves, and decades of future circumstances. Male lifespans of 5-10 years present less daunting commitment but still require dedicated care.

Family suitability depends on household members' comfort with spiders. Mexican Red Knees pose minimal danger—their mild venom produces only localized reactions comparable to bee stings, and bites are extremely rare. Urticating hairs cause temporary skin irritation. Children should be supervised during any interaction and educated about proper handling techniques and fall risks. Households with severe arachnophobia may find tarantula presence stressful regardless of the animal's containment.

Legal considerations apply to Mexican Red Knees as CITES-listed species. International trade requires permits, and only captive-bred specimens should be purchased. Some jurisdictions regulate tarantula ownership—verify local laws before acquiring. Reputable breeders provide documentation of captive-bred origin.

Realistic expectations should center on appreciation rather than interaction. Tarantulas do not recognize owners, seek affection, or form bonds. They are display animals that happen to tolerate occasional handling. The reward comes from observing natural behaviors, witnessing molts, maintaining an impressive specimen, and potentially breeding these fascinating creatures. Those expecting pet-like interaction will be disappointed, while those fascinated by invertebrates will find decades of enjoyment.