Monocentropus balfouri Care Guide

Socotra Island Blue Baboon

Revision Date: March 2025

Introduction

Monocentropus balfouri, commonly known as the Socotra Island Blue Baboon, is a striking Old World terrestrial species endemic to Socotra Island off the coast of Yemen. Renowned for its vivid blue and orange coloration, this tarantula stands out among Old World species despite lacking urticating hairs. While its overall temperament is relatively mellow for an Old World tarantula, it is fast and can bolt when startled. Notably, this species also exhibits an unusual communal tendency under the right conditions, making it an intriguing choice for intermediate keepers looking to explore group housing with proper experience.

Quick Species Snapshot

• Scientific Name: Monocentropus balfouri

• Common Name: Socotra Island Blue Baboon

• Type: Terrestrial, Opportunistic Burrower

• Category: Old World

• Endemic Location: Socotra Island (off the coast of Yemen)

• Body Length: Approximately 2.5” (7 cm)

• Diagonal Leg Span (DLS): Up to 7” (18 cm)

• Urticating Hairs: No

• Growth Rate: Slow

• Life Expectancy:

  • Females: 12–14 years

  • Males: 3–4 years

• Recommended Experience Level: Intermediate

What Makes Monocentropus balfouri So Special?

The Socotra Island Blue Baboon is admired for its stunning blue and orange coloration—a true visual delight among Old World tarantulas. Despite being an Old World species (and therefore lacking urticating hairs), it still exhibits a fast, defensive escape response if disturbed. Remarkably, this species can be kept communally when introduced early, a rarity among Old World tarantulas. Its natural, slow growth and relatively moderate size, combined with unique communal tendencies, make it an intriguing project for experienced hobbyists looking to expand their collection.

Taxonomy, Etymology & Natural Environment

Monocentropus balfouri, commonly known as the Socotra Island Blue Baboon Tarantula, is one of the most sought-after Old World species due to its stunning blue coloration, communal tendencies, and hardy nature. Described by Pocock in 1897, this species belongs to the Theraphosidae family and is endemic to Socotra Island, Yemen, an isolated landmass known for its unique and highly adapted wildlife.

The genus name Monocentropus comes from Greek, meaning "single spur", possibly referencing a morphological feature of this genus. The species name balfouri honors Sir Isaac Bayley Balfour, a Scottish botanist who contributed to the study of the flora and fauna of Socotra Island.

Natural Range & Habitat

M. balfouri is endemic to Socotra Island, an isolated ecosystem off the coast of Yemen. Socotra is characterized by arid, rocky landscapes, sparse vegetation, and extreme environmental conditions, with hot temperatures and seasonal rainfall. Unlike many baboon tarantulas that prefer deep burrows, M. balfouri often inhabits rock crevices, natural shelters, and shallow burrows, using silk to reinforce and modify its surroundings.

The island’s dry climate and fluctuating humidity make M. balfouri highly adaptable to low-moisture environments, thriving in conditions that would be challenging for other species. In captivity, this species does not require high humidity, making it relatively easy to care for compared to more moisture-dependent tarantulas.

Behavior & Temperament

Despite being an Old World species, Monocentropus balfouri is notoriously unique due to its communal tendencies. Unlike most tarantulas, which are highly solitary, M. balfouri has been observed coexisting peacefully in groups, even sharing burrows and tolerating each other during feeding. This makes it one of the few tarantulas capable of communal setups, though careful monitoring is still required.

While M. balfouri is not considered overly defensive, it is fast, reclusive, and will defend itself if provoked. Like other baboon species, it lacks urticating hairs, relying instead on its speed and potent venom for defense. Bites are reported to be painful but not medically significant, though they should still be avoided.

This species is also a heavy webber, often carpeting its enclosure in thick layers of silk, which adds to its appeal as a display tarantula.

Housing & Substrate – Semi-Arboreal 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.

• 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" Tarantula Cube, 8" Tarantula Cube, or Medium Cuboid) that is at least 3–4× the tarantula’s leg span.

• Substrate: Fill the enclosure 1/3 to 1/2 full with Terra Aranea by The Bio Dude. This depth allows for effective burrowing and minimizes 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 and include vertical branches, cork bark pieces, or small fake plants as web anchors to facilitate natural web tunnel construction.

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 still considering escape risks).

• Substrate: Fill the enclosure 1/3 to 1/2 full with Terra Aranea by The Bio Dude to provide ample depth for burrowing while reducing fall distance.

• Additional Features: Include a secure hide (preferably a half cork bark round), a shallow water dish, and tasteful decorations such as vertical branches or cork bark pieces leaned diagonally. Ensure the enclosure is a horizontal rectangle (wider than it is deep) with secure ventilation and a tight, secure lid to prevent escapes.

Note: "Semi‑arboreal" is not an official behavioral classification but rather a descriptive term used in the hobby to design enclosures that allow a tarantula to display some climbing and web anchoring behavior without exposing it to dangerous falls. For semi‑arboreal species, the enclosure is typically a square or horizontal rectangle rather than a tall arboreal setup. This design minimizes fall distance and risk of injury. Never use an arboreal enclosure for a species that is not truly arboreal.

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

Temperature & Humidity

• Temperature: Maintain ambient temperatures between 68°F and 76°F (20°C to 24°C).

• Humidity: Aim for moderate humidity. Ensure the substrate remains moist in the lower layers for effective burrowing while allowing the top layers to dry out between waterings to prevent mold.

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.

Breeding Monocentropus balfouri in Captivity

Breeding Monocentropus balfouri (Socotra Island Blue Baboon) in captivity is both rewarding and challenging, given their unique behaviors and communal tendencies. With meticulous preparation and understanding of their natural history, enthusiasts can successfully propagate this remarkable species.

Sexual Maturity & Pairing

• Male Maturity: Males typically reach maturity within 2–3 years, developing longer legs and bulbous pedipalps for sperm transfer.

• Female Maturity: Females generally mature around 3–4 years, achieving a robust size indicative of reproductive readiness.

• Pre-Pairing Preparation: We should ensure the female is well-fed before introducing the male to minimize the risk of cannibalism. Given their communal nature, M. balfouri often exhibit less aggression during pairing compared to other tarantula species.

Mating Process

• Introduce the male into the female’s enclosure during the evening or nighttime when tarantulas are more active.

• The male will typically perform courtship behaviors, such as tapping or drumming, to signal his presence.

• If receptive, the female may respond with similar behaviors or remain still, allowing the male to approach and attempt copulation.

• After successful mating, the male can often remain in the enclosure without immediate risk, but monitoring is advised to ensure safety.

Egg Sac Production

• If fertilized, the female may produce an egg sac approximately 4–8 weeks after mating.

• Maintain temperatures around 75–80°F (24–27°C) with humidity levels between 65–75%, ensuring adequate ventilation to prevent mold growth.

• An egg sac can contain a substantial number of eggs, with reports indicating clutches ranging from 20 to 40 eggs.

Egg Sac Handling (Optional)

• Unlike some tarantula species, M. balfouri exhibits maternal care, with females tending to their offspring. It is often beneficial to leave the egg sac with the mother to allow natural rearing.

• Spiderlings (slings) will typically emerge within 6–8 weeks and remain with the mother for an extended period, during which she may provide food for them.

Raising Spiderlings

• M. balfouri spiderlings exhibit a medium growth rate and thrive in communal settings.

• Provide enclosures with sufficient substrate to accommodate their burrowing behavior and include structures for web attachment.

• Feed them appropriately sized prey, such as pinhead crickets or flightless fruit flies, every 2–3 days to support healthy development.

Challenges & Considerations

• Communal Behavior: M. balfouri is one of the few tarantula species known to thrive in communal setups. However, careful monitoring is essential to ensure all individuals are feeding well and exhibiting normal behaviors.

• Environmental Sensitivity: Maintaining proper humidity levels is crucial, as spiderlings are particularly susceptible to desiccation.

• Temperament: While generally less defensive than other Old World species, M. balfouri can be fast and reclusive. Caution is advised during maintenance to avoid stress or escape.

Final Thoughts

There’s no other tarantula quite like Monocentropus balfouri. That electric blue coloration, the intricate web tunnels, and the ability to live communally make them one of the most fascinating species in the hobby. Watching a mother tend to her slings is an experience that sets this species apart from the rest. If you’re looking for a truly unique tarantula with stunning colors and incredible behavior, M. balfouri is an absolute must-have.

Additional Recommendations:
For enclosures, consider Tarantula Cribs with the affiliate code TTC10 for a 10% discount, and use Terra Aranea by The Bio Dude for substrate. For purchasing tarantulas online, check out Spider Shoppe (use code TTC10 for 10% off). Also, visit the Dealer & Discounts section on my website for a curated list of recommended dealers and discount codes.

Additional Scientific Information

• Size & Growth:
  Monocentropus balfouri has a relatively small body length (~2.5 inches) but can achieve an impressive leg span of up to 7 inches. Its slow growth rate means that it may take several years to reach full adult size, with females living 12–14 years and males only 3–4 years.

• Ecological Role:
  Native to the isolated ecosystem of Socotra Island, this species plays a unique role in controlling insect populations in arid, rocky environments. Its opportunistic burrowing helps aerate the soil and contributes to nutrient recycling.

• Behavioral & Social Insights:
  Although many Old World tarantulas are solitary, M. balfouri has been observed living communally under the right conditions. This communal behavior is rare among Old World species and can offer fascinating insights into their social dynamics when introduced early.

• Handling & Welfare:
  With no urticating hairs to rely on for defense, M. balfouri primarily uses speed and, occasionally, biting as its defensive mechanisms. Due to their fast movement and potential territoriality in communal setups, minimal handling is recommended. Extra caution is advised when cleaning enclosures or rehousing individuals.

(For further reading, consult recent publications in the Journal of Arachnology and ZooKeys for detailed ecological and taxonomic studies on Old World Theraphosidae.)