Mexican Red-Knee Tarantula (Brachypelma hamorii) Care Sheet
Quick Facts
Common Name: Mexican Red-Knee Tarantula
Scientific Name: Brachypelma hamorii
Family: Theraphosidae
Native Range: Mexico
Adult Leg Span: Approximately 12–15 cm (5–6 in)
Lifestyle: Terrestrial, opportunistic burrower
Activity: Primarily crepuscular/nocturnal
Diet: Invertebrates
Growth Rate: Slow
Temperament: Generally calm but individuals vary
Defence: Urticating hairs; may also adopt a threat posture or bite
Lifespan: Females can live 20–30+ years; males have considerably shorter adult lifespans
Experience Level: Beginner to intermediate
Introduction
The Mexican Red-Knee Tarantula (Brachypelma hamorii) is one of the best-known tarantulas in captivity.
Its striking black body and orange-red markings on the legs have made it an iconic species within the hobby.
It is a terrestrial tarantula native to Mexico and is generally slow-moving and relatively defensive only when disturbed.
However, describing any tarantula as completely “docile” can be misleading. Individual temperament varies, and even normally calm animals can react defensively.
Like other New World terrestrial tarantulas, Brachypelma hamorii possesses urticating hairs on the abdomen which can be released when threatened.
The species is exceptionally slow-growing compared with many other commonly kept invertebrates.
Females can live for decades, making this a surprisingly long-term commitment.
Taxonomy – B. hamorii vs B. smithi
The Mexican Red-Knee has a complicated history within the reptile and invertebrate hobby.
For many years, numerous spiders maintained and sold as:
Brachypelma smithi
were actually:
Brachypelma hamorii
Modern taxonomic work has confirmed that B. hamorii and B. smithi are separate species.
Both remain valid species.
Because of the long history of misidentification, older books, websites and captive records may incorrectly identify B. hamorii as B. smithi.
Colour pattern alone should not always be regarded as sufficient for definitive identification.
Natural Range & Habitat
Brachypelma hamorii is native to Mexico.
It inhabits seasonally dry environments rather than permanently wet tropical rainforest.
Wild individuals utilise burrows and natural retreats which provide protection from:
- Temperature extremes
- Predators
- Dehydration
- Disturbance
Burrows also create a more stable microclimate than the exposed surface environment.
This is important when designing a captive enclosure.
Mexican Red-Knees require access to a secure retreat and suitable substrate rather than an exposed enclosure containing only a thin layer of decorative material.
Size
Adult Mexican Red-Knees commonly achieve a leg span of approximately:
12–15 cm (5–6 inches)
Females generally become heavier-bodied and substantially longer-lived than males.
Growth is relatively slow.
Spiderlings may take several years to develop into mature animals, with growth rate influenced by:
- Temperature
- Feeding
- Sex
- Genetics
- Individual variation
Fast growth should not be regarded as a husbandry objective.
Lifespan
One of the most important considerations before acquiring this species is its longevity.
Females can potentially live:
20–30 years or more
under suitable captive conditions.
Males have much shorter lifespans.
After reaching sexual maturity, males typically live for a relatively limited period compared with females.
A young female Mexican Red-Knee can therefore represent a commitment comparable to many long-lived reptiles.
Enclosure
Mexican Red-Knees are terrestrial tarantulas.
Floor space is considerably more important than height.
For an adult, an enclosure approximately:
30 × 30 × 30 cm
can provide suitable accommodation when properly furnished.
A somewhat larger enclosure can also be used provided that:
- The spider can easily locate prey
- Suitable cover is available
- Fall distances remain safe
- Environmental conditions remain appropriate
Excessive enclosure height should be avoided.
A heavy-bodied terrestrial tarantula can be seriously injured or killed by a relatively short fall.
The distance between the top of the substrate and enclosure roof should therefore be kept modest.
The enclosure must be secure but well ventilated.
Substrate
Provide a deep layer of substrate.
Approximately:
10–15 cm
is suitable for an adult enclosure, with additional depth beneficial where enclosure design permits.
Suitable substrate can include mixtures of:
- Coco fibre
- Chemical-free topsoil
- Reptile/invertebrate-safe soil
- Excavator-type soil mixtures
The substrate should be sufficiently compacted to support excavation.
Extremely loose, fluffy substrate is less useful for a burrowing terrestrial tarantula.
Avoid:
- Cedar
- Chemically treated soil
- Fertilised compost
- Sharp gravel
- Calcium sand
- Permanently saturated substrate
The enclosure should generally remain relatively dry, although some moisture can be maintained in part of the lower substrate.
Spiderlings require somewhat greater attention to moisture because they dehydrate more rapidly than large adults.
Hide
Every Mexican Red-Knee should have access to a secure retreat.
Suitable hides include:
- Cork bark
- Half-buried cork tubes
- Artificial caves
- Other dark, stable retreats
Partially burying a piece of cork bark can provide the beginning of a burrow which the spider can enlarge itself.
The hide should be large enough for the tarantula to enter comfortably but secure enough to provide a sense of enclosure.
Do not continually disturb or excavate a spider simply because it spends long periods hidden.
Extended periods inside a burrow are completely normal.
Temperature
Mexican Red-Knees do not require extreme heat.
A general temperature range of approximately:
20–25°C
works well for most established animals.
Slight natural variation between day and night is acceptable.
Normal indoor room temperatures are therefore often adequate.
Temperatures should not be deliberately pushed excessively high in an attempt to accelerate growth.
If supplementary heating is genuinely necessary because the room is too cold, it should warm the environment gently rather than creating a dangerously hot surface.
Heating
Direct heating of a tarantula enclosure is usually unnecessary in a normally heated home or reptile room.
Avoid:
- Heat rocks
- Uncontrolled heat mats
- High-powered basking lamps
- Heating the entire enclosure excessively
Tarantulas cannot thermoregulate in the same manner as a basking reptile.
If additional room heating is required, heating the room itself is generally preferable.
Where external enclosure heating must be used, it should be carefully thermostatically controlled and positioned so that the spider can retreat away from it.
Never place uncontrolled heating beneath the entire enclosure.
Humidity & Moisture
Mexican Red-Knees should not be maintained in permanently wet tropical conditions.
Rather than attempting to maintain a precise humidity percentage, concentrate on providing:
- A water dish
- Good ventilation
- Mostly dry surface substrate
- Some access to moisture in deeper substrate
- Appropriate moisture for spiderlings
Allowing a portion of the substrate to remain slightly moist can create a useful moisture gradient.
The surface can generally remain substantially drier.
Constant misting is unnecessary and can create excessively damp, stagnant conditions.
Good ventilation is extremely important.
Water
Fresh water should be available at all times.
Provide a shallow water dish.
The dish should be:
- Easy for the spider to access
- Stable
- Kept clean
- Refilled regularly
Tarantulas will not drown simply because an appropriately shallow water dish is present.
Placing sponges or cotton wool in the water is unnecessary and can encourage bacterial growth.
Spiderlings too small for a conventional water bowl can be managed with appropriately scaled hydration methods until they are large enough to use a small dish safely.
Lighting
Special reptile lighting is not required.
Tarantulas do not require:
- UVB lighting
- Basking lamps
- Bright specialist lighting
Normal ambient room lighting can provide an appropriate day/night cycle.
Avoid placing the enclosure in:
- Direct sunlight
- Strong heat-producing light
- Locations exposed to excessive temperature fluctuations
Direct sunlight through glass can cause an enclosure to overheat rapidly.
Furnishings
A relatively simple enclosure is usually best.
Suitable furnishings include:
- Cork bark
- A secure hide
- Artificial plants
- Small amounts of leaf litter
- Other lightweight decorative material
Avoid heavy rocks or decorations that could collapse onto a burrowing spider.
All furnishings should be positioned securely.
The enclosure should not contain sharp objects capable of damaging the spider’s abdomen.
Feeding
Mexican Red-Knees are predatory invertebrates.
Suitable captive prey includes:
- Crickets
- Locusts
- Dubia roaches
- Other appropriately sized captive-bred roaches
- Mealworms
- Superworms for appropriately sized adults
- Other suitable feeder insects
A varied diet is beneficial.
Adult tarantulas generally require much less food than many new keepers expect.
A healthy adult may be offered approximately:
1–2 appropriately sized prey items every 7–14 days
depending upon prey size and the spider’s body condition.
Juveniles can be fed somewhat more frequently.
Spiderlings can receive appropriately sized small prey more regularly.
Feeding schedules should be adjusted according to:
- Abdomen condition
- Age
- Growth
- Temperature
- Prey size
- Premoult behaviour
Tarantulas can go for surprisingly long periods without eating.
A refusal to feed is not automatically an emergency.
Body Condition & Overfeeding
The abdomen provides useful information about body condition.
A severely shrunken abdomen can indicate dehydration or poor condition.
Conversely, an excessively large abdomen increases the potential consequences of a fall or abdominal injury.
Do not continually feed an adult simply because it accepts food.
Slow-growing Brachypelma species do not require constant heavy feeding.
Premoult
Tarantulas periodically moult their exoskeleton in order to grow.
Signs that a Mexican Red-Knee may be approaching a moult include:
- Refusing food
- Reduced activity
- Increased hiding
- Increased webbing
- Darkening of the abdomen
- A dark bald patch on the abdomen
- Sealing the entrance to its retreat
Premoult can last for a considerable period.
Do not disturb a spider that has sealed itself inside a burrow.
Moulting
During moulting, the tarantula will commonly lie on its back.
This is normal.
A tarantula lying on its back should not be assumed to be dead.
Do not:
- Turn it over
- Touch it
- Move it
- Attempt to assist the moult
- Offer live prey
The process can take several hours.
Following the moult, the new exoskeleton and fangs are extremely soft.
The spider must be allowed to harden before feeding resumes.
For a large adult, waiting approximately:
7–14 days
before offering food is generally appropriate.
Smaller juveniles may harden more quickly.
Any uneaten live prey should be removed immediately because feeder insects can injure a vulnerable moulting tarantula.
Urticating Hairs
Mexican Red-Knees possess defensive urticating hairs on the abdomen.
When threatened, the spider may use its hind legs to kick these hairs into the air.
The hairs can cause:
- Skin irritation
- Itching
- Rash
- Eye irritation
- Respiratory irritation
Contact with the eyes can be particularly serious.
Avoid placing your face close to the enclosure when disturbing substrate or carrying out maintenance.
Wash your hands after enclosure maintenance.
If urticating hairs enter the eyes or cause significant respiratory symptoms, seek appropriate medical attention.
Defensive Behaviour
Although Brachypelma hamorii is often described as calm, individual temperament varies.
A threatened animal may:
- Retreat
- Kick urticating hairs
- Raise its front legs
- Display its fangs
- Strike
- Bite
A threat posture should be respected.
Do not deliberately provoke defensive behaviour for photographs or entertainment.
Handling
Routine handling is not recommended.
This is not primarily because Brachypelma hamorii is exceptionally aggressive.
The greatest danger during handling may actually be to the tarantula.
A terrestrial tarantula has a relatively delicate abdomen.
A fall from human hand height can rupture the abdomen and may be fatal.
Handling also exposes the keeper to:
- Urticating hairs
- Defensive bites
- Unexpected rapid movement
Tarantulas do not require handling for socialisation or psychological wellbeing.
For enclosure maintenance or transfers, using a suitable catch cup is safer for both the spider and keeper.
Venom & Bites
Like almost all tarantulas, Brachypelma hamorii possesses venom used to subdue prey.
A defensive bite is possible.
Bites from this species are not generally regarded as medically significant in healthy adults, but reactions can vary.
Any bite should be cleaned appropriately.
Seek medical advice if significant pain, swelling, allergic-type symptoms or other concerning effects occur.
The absence of severe venom does not make deliberately handling or provoking the animal appropriate.
Sexing
Adult males and females become increasingly different as they mature.
Mature males develop reproductive structures including:
- Emboli on the pedipalps
- Tibial hooks/apophyses characteristic of mature males in this group
- A more slender overall appearance
Females generally remain heavier-bodied.
The most reliable method of sexing immature animals is examination of a suitable moult, particularly the internal abdominal area for female spermathecae.
External ventral sexing can sometimes provide an indication but is less definitive.
Housing Individually
Mexican Red-Knees should be housed individually.
They are not social animals.
Cohabitation creates a risk of:
- Stress
- Injury
- Cannibalism
Even males and females should only be introduced deliberately for breeding and under appropriate supervision.
Cleaning
Tarantula enclosures generally require relatively little disturbance.
Remove:
- Uneaten prey
- Prey remains
- Mould
- Contaminated substrate
- Other waste
Water dishes should be cleaned regularly.
A complete substrate replacement is not required on an arbitrary frequent schedule if the enclosure remains clean and healthy.
Unnecessary complete enclosure changes can destroy established burrows and cause stress.
Spot cleaning is generally preferable.
Health
Healthy tarantulas generally display:
- Appropriate body condition
- Coordinated movement
- Normal feeding or fasting patterns
- Successful moulting
- Normal use of their retreat
Potential problems include:
Dehydration
Possible signs include a shrunken abdomen, weakness or abnormal posture.
Provide access to clean water and ensure environmental conditions are appropriate.
Moulting Problems
Dysecdysis can occasionally occur.
Never attempt to pull a tarantula from its old exoskeleton without specialist guidance.
Abdominal Injury
Falls can rupture the abdomen.
This is one of the main reasons excessive enclosure height and routine handling should be avoided.
Mites & Pests
Small organisms within an enclosure are not automatically parasitic mites.
However, unusual organisms attached directly to the spider, particularly around the mouthparts, should be investigated.
DKS-Like Neurological Signs
Uncoordinated movement, abnormal leg positioning or inability to walk normally requires specialist assessment.
Veterinary treatment of tarantulas is specialised, so where professional help is required, seek a veterinarian or experienced exotic invertebrate specialist familiar with arachnids.
Breeding
Breeding Brachypelma hamorii should only be attempted by keepers familiar with tarantula reproductive behaviour.
A mature male can be introduced carefully to a receptive mature female.
The enclosure should provide sufficient space for the male to retreat.
Courtship involves characteristic tapping and vibratory behaviours.
The male uses his specialised pedipalps to transfer sperm to the female.
Breeding introductions must be supervised because females can attack or consume males.
The pair should be separated following mating.
Egg Sac
Following successful mating, a female may eventually construct an egg sac.
Reproductive timing can vary considerably.
The female may become extremely defensive while guarding the sac.
Disturbance should be kept to a minimum.
Egg sacs can contain hundreds of eggs, although reproductive success and numbers vary substantially.
Incubation and artificial management of tarantula egg sacs are specialist breeding subjects and should be researched thoroughly before breeding is attempted.
Spiderling Care
Spiderlings require appropriately scaled accommodation.
Small ventilated containers can work well provided they are secure.
Spiderlings require:
- Suitable moisture
- Good ventilation
- Appropriately sized prey
- Secure hiding opportunities
- Stable temperatures
Very small spiderlings are more vulnerable to dehydration than established adults.
Suitable prey may include:
- Small cricket nymphs
- Tiny roach nymphs
- Fruit flies
- Pieces of freshly killed larger prey where appropriate
As the spider grows, the enclosure should be upgraded gradually.
Avoid placing a tiny spiderling into an excessively large enclosure where monitoring feeding and hydration becomes difficult.
Conservation & Trade
Brachypelma tarantulas are subject to international wildlife-trade controls.
Captive-bred animals should always be preferred.
Responsible acquisition helps reduce pressure on wild populations and provides the keeper with an animal of known captive origin.
Potential owners should ensure that acquisition, sale and movement comply with any applicable wildlife-trade regulations.
Summary
The Mexican Red-Knee Tarantula is one of the most iconic species maintained in the invertebrate hobby.
Successful husbandry centres around:
- A terrestrial rather than tall enclosure
- Deep, compactable substrate
- A secure retreat
- Safe fall distances
- Moderate temperatures
- Good ventilation
- Mostly dry surface conditions
- Permanent access to fresh water
- Appropriate feeding without overfeeding
- Respect for premoult and moulting behaviour
- Individual housing
- Minimal unnecessary disturbance
- Avoidance of routine handling
The key principle is that Brachypelma hamorii is a slow-growing terrestrial burrowing tarantula, not a display animal that needs constant feeding, misting or handling.
When maintained appropriately, females can live for decades and make fascinating long-term captive invertebrates.
Important: This care sheet provides general husbandry guidance. Individual animals may require adjustments according to age, size, sex and condition. Tarantulas should be handled only when necessary, and significant health concerns should be discussed with a veterinarian or experienced specialist familiar with exotic invertebrates.