Mexican Red Knee Tarantula

Brachypelma hamorii Care Guide

The Mexican Red Knee Tarantula

Revision Date: March 2025

Introduction

Alright, today we’re talking about Brachypelma hamorii (formerly B. smithi), also known as the Mexican Red Knee Tarantula. This species is one of the most iconic tarantulas in the hobby. With its striking black and orange coloration and calm demeanor, it’s a go-to species for many enthusiasts. Whether you’re new to the hobby or just looking for a reliable starter, this tarantula is an excellent choice thanks to its relatively easy care requirements and docile nature.

Quick Species Snapshot

• Scientific Name: Brachypelma hamorii

• Common Names: Mexican Red Knee Tarantula

• Type: Terrestrial

• Native Range: Mexico (primarily along the western coast south of Guadalajara)

• Size: Approximately 5.5” diagonal leg span (about 14 cm)

• Growth Rate: Medium – Slow

• Life Expectancy: Females 25-30 years / Males around 10 years

• Experience Level: Beginner

What Makes B. hamorii So Special?

The Mexican Red Knee Tarantula is beloved for its striking appearance, vivid black with contrasting bright orange markings on the legs give it a unique, memorable look. Known for its calm and docile temperament, it’s often the first tarantula many hobbyists encounter. Its relatively forgiving care requirements make it a perfect choice for beginners, while its impressive lifespan ensures that it can be a long-term addition to your collection.

A Species at Risk

While Brachypelma hamorii is popular in the pet trade, it’s important to note that habitat loss in Mexico has affected wild populations. Additionally, this species has been subject to smuggling in the past. For these reasons, it’s best to acquire captive-bred specimens from reputable breeders.

Natural Habitat & What That Means for Enclosure Setup

In the wild, the Mexican Red Knee is found in the drier savannas and scrublands of Mexico, where temperatures can range from warm and dry to cooler and slightly humid in higher altitudes. In captivity, mimicking this environment by providing a substrate deep enough for burrowing is key. A setup that allows for some variation, such as a slightly moist area alongside a drier zone, can help your tarantula regulate its temperature and humidity levels naturally.

Housing & Substrate – Terrestrial Setup

Spiderlings

• Enclosure Size:
  Use a small acrylic enclosure (e.g., Sling Crib, 3" Tarantula Cube, Small Slider Crib, Small Cuboid, Terrestrial Sling Crib, Slider Crib Mini, or Cuboid Mini) that is no smaller than three times the tarantula’s leg span. We recommend enclosures by Tarantula Cribs for their proven quality and safety.

• Substrate:
  Fill at least 2/3rds of the enclosure with Terra Aranea by The Bio Dude.

• Humidity:
  Maintain a slightly damp substrate (but not swampy) by offering a small water dish or gently dripping water on one corner about once a week.

Juveniles

• Enclosure Size:
  Use a medium enclosure (e.g., Medium Slider Crib, 6" or 8" Tarantula Cube, or Medium Cuboid) that is at least 3–4× the tarantula’s leg span.

• Substrate:
  Fill the enclosure 1/2 to 2/3 full with Terra Aranea by The Bio Dude. This depth ensures ample space for burrowing while minimizing the risk of injury from falls.

• Humidity:
  Keep the substrate mostly dry with a full water dish; occasionally overflow one corner to create a slightly damp area.

• Additional Features:
  Provide a half cork bark round for a secure hide.

Adults

• Enclosure Size:
  Use a large enclosure (e.g., Large Slider Crib, 12" Cube Switch, 12" Cube, 18" Cube, or Terrestrial XL) that is at least 3× the tarantula’s leg span (ideally 4× for enhanced natural behavior, while considering escape risks). Enclosures by Tarantula Cribs are highly recommended.

• Substrate:
  Fill the enclosure 1/2 to 2/3 full with Terra Aranea by The Bio Dude to provide sufficient depth for burrowing while reducing the risk of falls.

• Additional Features:
  Include a secure hide (preferably a half cork bark round) and a shallow water dish. Ensure the enclosure is a horizontal rectangle (wider than it is deep) with secure ventilation and a tight, secure lid to prevent escapes.

Note:
The general rule of thumb for tarantula enclosures is that the enclosure should be no smaller than three times the tarantula’s leg span for spiderlings, 3–4× for juveniles, and 3–4× for adults. This ensures ample space for natural burrowing while minimizing fall risk. Remember, tarantulas are escape artists, so always verify that ventilation holes, lids, and gaps are too small for your tarantula to squeeze through. They can and will climb glass and other smooth surfaces.

Affiliate: Please use Tarantula Cribs (affiliate code TTC10) and Terra Aranea by The Bio Dude for substrate.

Temperature & Humidity

• Temperature: Around 70-78°F (21-25°C) — standard room temperatures are usually ideal.

• Humidity: Moderate; try to keep a portion of the substrate slightly damp and ensure the water dish is consistently filled.

Feeding Schedule

Spiderlings

• Frequency:
  Feed twice a week.

• Prey:
  Offer small prey such as flightless fruit flies, confused flour beetles, or pre-killed tiny crickets/roach nymphs. Remove any uneaten prey after 24 hours. increase the size of the prey as the spider grows. Prekill any prey that is over 2/3 the size of the sling. For more detailed information on feeding spiderlings, watch this video: How To Feed Spiderlings & Scorplings (Baby Tarantulas & Scorpions)

• Post-Molt:
  Wait 24–48 hours after a molt before feeding. Ensure that the tarantula’s fangs are solid black and its exoskeleton is not soft or shiny.

Juveniles

• Frequency:
  Feed every 7–10 days.

• Prey:
  Provide 2–3 small to medium crickets or a medium Dubia roach.

• Feeding Guidelines:

  • If the abdomen is thinner than the widest part of the carapace, feed more prey more often.

  • If the abdomen is wider than the carapace, feed less prey, less often.
    This strategy helps prevent obesity, which can lead to molting complications or increase the risk of an abdomen rupture from even a small fall.

• Post-Molt:
  Wait 3–7 days after a molt before feeding, ensuring that the tarantula’s fangs are solid black and its exoskeleton is fully hardened.

Adults

• Frequency:
  Feed every 2–3 weeks (or as needed).

• Prey:
  Offer 4–5 large crickets or one large Dubia roach.

• Feeding Guidelines:

  • If the abdomen is thinner than the carapace’s widest part, increase feeding frequency.

  • If the abdomen is wider than the carapace, reduce feeding frequency.
    This is crucial to avoid obesity, which can interfere with proper molting or cause dangerous issues such as an abdomen rupture.

• Post-Molt:
  Wait 5–10 days after a molt before feeding, ensuring that the tarantula’s fangs are solid black and its exoskeleton is fully hardened.

Behavior & Temperament

The Mexican Red Knee is well-known for its calm and docile demeanor. Although they can be a bit skittish when young, they generally retreat into their burrow when disturbed rather than displaying aggression. Their venom is not medically significant, and while their urticating hairs might cause mild irritation if disturbed, they are considered very beginner-friendly. Their active burrowing behavior and occasional reclusive periods make them excellent display animals.

Breeding Brachypelma hamorii in Captivity

Breeding Brachypelma hamorii (Mexican Red Knee Tarantula) is a slow but rewarding process due to their long maturation period and selective mating behavior. As a CITES-protected species, captive breeding is essential to maintain healthy populations in captivity while ensuring that wild specimens remain undisturbed.

Sexual Maturity & Pairing

• Male Maturity: Males mature in 4–7 years, developing tibial hooks and enlarged pedipalps for sperm transfer.

• Female Maturity: Females take significantly longer, often 8–12 years, before they are fully mature and receptive.

• Pre-Pairing Preparation: We should ensure the female is well-fed before pairing to reduce defensive responses. Some breeders also recommend increasing humidity slightly before pairing to simulate seasonal breeding triggers.

Mating Process

• Introduce the male at night, when both tarantulas are naturally more active.

• The male will drum on the substrate to signal his presence.

• If receptive, the female may drum back or remain still, allowing the male to lift her with his tibial hooks and insert his emboli.

• Once mating is complete, the male should be removed immediately, as B. hamorii females can become defensive afterward.

Egg Sac Production

• If fertilization is successful, the female will begin producing an egg sac 4–6 months after mating.

• Maintain temperatures around 72–78°F (22–25°C) with humidity levels of 60–70% to support egg sac development.

• The egg sac typically contains 400–800 eggs, though clutch size can vary.

Egg Sac Handling (Optional)

• Some breeders prefer to pull the egg sac after 30–45 days for artificial incubation.

• If left with the mother, 1st instar spiderlings will emerge in 8–10 weeks, molting into 2nd instar within 3–4 weeks.

Raising Spiderlings

• Once the spiderlings reach 2nd instar, we should separate them into individual enclosures.

• Feed them pinhead crickets, flightless fruit flies, or small roaches every 3–4 days.

• Maintain moderate humidity while allowing part of the enclosure to dry out between mistings to prevent mold growth.

Challenges & Considerations

• Female selectiveness: Some females may reject males outright, requiring multiple introductions before successful pairing.

• Long maturation time: With slow growth rates, breeding B. hamorii requires years of patience and commitment.

• Male lifespan: Males typically do not live beyond a year after maturing, so breeding attempts should be made as soon as possible.

Since Brachypelma hamorii is a CITES-protected species, it is critical that we prioritize captive breeding efforts over wild collection. By continuing to breed this species in captivity, we help ensure a stable, self-sustaining population while reducing the demand for wild-caught specimens. Every successful breeding project strengthens the future of this species in both the hobby and conservation efforts.

Final Thoughts

The Brachypelma hamorii is one of the most iconic tarantulas in the hobby for a reason. With their striking red knees, long lifespan, and generally calm temperament, they make a fantastic choice for keepers of all experience levels. While they may grow slowly, the wait is well worth it, these spiders thrive in captivity when provided with the right setup, making them a joy to observe for decades.

By focusing on captive-bred specimens, we ensure that wild populations stay where they belong, in the wild. With B. hamorii being a CITES-protected species, it’s up to us as keepers and breeders to do our part in maintaining sustainable captive populations. If you’re lucky enough to own one of these beauties, you’re caring for a piece of tarantula history, and that’s something truly special.

With proper care, patience, and respect for their natural behaviors, Brachypelma hamorii will reward you with a lifetime of enjoyment. Whether you're new to the hobby or a seasoned keeper, this species is a must-have for any collection.

Additional Recommendations:
For enclosures, you might consider Tarantula Cribs with affiliate code TTC10 for a 10% discount, and I suggest using Terra Aranea by The Bio Dude for substrate. For purchasing tarantulas online, a great option is Spider Shoppe — just use code TTC10 for 10% off. Also, check out the Dealer & Discounts section on my website for a list of other recommended dealers with discount codes.