Ceratogyrus marshalli Care Guide

The Straight Horned Baboon Tarantula

Revision Date: March 2025

Introduction

Ceratogyrus marshalli, commonly known as the Straight Horned Baboon Tarantula, is a striking Old World fossorial species native to Zimbabwe, Mozambique, and surrounding regions. It is instantly recognizable due to its unique foveal horn, which stands straight up from the carapace, giving it a menacing yet fascinating appearance. Like other members of the Ceratogyrus genus, this species is an obligate burrower and thrives in deep substrate where it can construct intricate tunnel systems.

This species is not for beginners due to its defensive temperament, strong venom, and lightning-fast movements. However, for experienced keepers looking to add a fascinating African fossorial species to their collection, C. marshalli is an excellent choice.

Quick Species Snapshot

• Scientific Name: Ceratogyrus marshalli

• Common Name: Straight Horned Baboon Tarantula

• Type: Fossorial (Obligate Burrower)

• Category: Old World

• Native Range: Zimbabwe, Mozambique

• Size: Up to 5” (13 cm) DLS

• Growth Rate: Medium to Fast

• Life Expectancy: Females 13–15 years / Males 2–4 years

• Experience Level: Intermediate

• Urticating Hairs: No

• Venom Potency: Strong (painful bite, symptoms include muscle cramping, nausea, and headaches)

Taxonomy, Etymology & Natural Environment

Ceratogyrus marshalli, commonly known as the Straight-Horned Baboon Tarantula, is a striking Old World species belonging to the Harpactirinae subfamily of tarantulas, which are native to Africa. This species is particularly recognizable due to the distinctive foveal horn that protrudes from the top of its carapace, a feature unique to the Ceratogyrus genus. Originally described in 1897 by British arachnologist Reginald Innes Pocock, C. marshalli is one of the more well-known species within the genus and is highly sought after by experienced tarantula keepers due to its bold personality, speed, and defensive nature.

The genus name Ceratogyrus is derived from the Greek words "keratos", meaning "horned," and "gyros", meaning "round" or "curved," referring to the distinctive carapace protrusions found in species of this genus. The species name marshalli honors Sir Guy Anstruther Knox Marshall, an entomologist and naturalist known for his contributions to African insect research.

Behavior & Temperament

Like many Old World tarantulas, C. marshalli is fast, defensive, and prone to standing its ground when threatened. While it may not be as defensive as some Asian arboreal species like Poecilotheria or Ornithoctoninae tarantulas, it will not hesitate to throw up a threat posture or deliver a bite if provoked. Unlike New World species, it lacks urticating hairs, meaning its primary defenses are its speed, venom, and strong fangs.

Although bites from C. marshalli are not considered medically significant to humans, they are reported to be painful, causing localized swelling, muscle cramping, and discomfort for several hours. Due to its bold nature, quick movements, and potent venom, this species is not recommended for beginners and is best suited for keepers with experience handling Old World tarantulas.

Adaptability & Captive Care

Despite its defensive nature, C. marshalli is a hardy and adaptable species in captivity. It thrives in a dry, well-ventilated enclosure with deep substrate for burrowing. Unlike tropical species, it does not require high humidity levels, and excessive moisture can lead to health issues. Instead, it prefers a semi-arid setup with occasional misting or a water dish for hydration.

Thanks to its striking appearance, unique horned carapace, and fascinating burrowing behaviors, Ceratogyrus marshalli has become a prized species among experienced tarantula enthusiasts. However, its speed, defensiveness, and potent venom make it a species that demands respect and careful husbandry.

Natural Range & Habitat

Ceratogyrus marshalli is native to Zimbabwe, Botswana, and parts of South Africa, where it thrives in dry, open savannas and scrublands. This species is a fossorial tarantula, meaning it spends most of its life in deep burrows that it excavates in loose, sandy soil. These burrows provide protection from the extreme heat and occasional heavy rains characteristic of its native environment. Unlike some arboreal or opportunistic burrowers, C. marshalli is a true obligate burrower, meaning a deep substrate is essential for its well-being in captivity.

The foveal horn found on C. marshalli and other Ceratogyrus species has been the subject of speculation among researchers and hobbyists. While its exact function is still debated, some theories suggest it may aid in structural reinforcement of the carapace, serve a sensory function, or assist with thermoregulation in hot environments. Regardless of its purpose, this feature makes C. marshalli one of the most recognizable African tarantulas in the hobby.

Housing & Substrate – Fossorial Setup

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Spiderlings

• Enclosure Size: OG Sling Crib, 3” Tarantula Cube, 4” Tarantula Cube

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

• Humidity: Keep the substrate slightly damp, but not swampy. Provide a tiny water dish if space allows or drip water onto webbing weekly.

Juveniles

• Enclosure Size: Crib 360-4” Fossorial, 5” Hex Crib, 6” Tarantula Cube, 8” Cube

• Substrate: Fill ½ to ¾ of the enclosure with Terra Aranea by The Bio Dude to support deep burrowing.

• Humidity: Let part of the substrate dry out while keeping one corner slightly damp by overflowing the water dish occasionally.

• Additional Features: Cork bark or dried leaves as web anchors.

Adults

• Enclosure Size: 8” Hex Crib, Crib 360-8” Fossorial, 12” Tarantula Cube, 18” Tarantula Cube

• Substrate: Fill at least ½–¾ of the enclosure with Terra Aranea by The Bio Dude.

• Additional Features: A deep burrow setup is essential. I like to add some branches or plants so they can web up around their burrow entrance as well.

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Temperature & Humidity

• Temperature: 70–80°F (21–27°C)

• Humidity: 50–60%

• Ventilation: Ensure good airflow to prevent stale conditions.

• Water Dish: Keep one filled and overflow occasionally to maintain a moisture gradient.

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 Ceratogyrus marshalli in Captivity

Breeding Ceratogyrus marshalli (Straight-Horned Baboon Tarantula) can be a rewarding yet high-risk process due to their fast growth rate, defensive nature, and unpredictable behavior toward mates. This species is known for its large egg sacs and rapid development, making captive breeding an excellent way to maintain sustainable populations in the hobby while ensuring that wild populations remain undisturbed.

Sexual Maturity & Pairing

• Male Maturity: Males mature quickly, usually within 2–3 years, developing tibial hooks and enlarged pedipalps for sperm transfer.

• Female Maturity: Females take 3–4 years to reach reproductive maturity, which is relatively fast compared to many other species.

• Pre-Pairing Preparation: We should ensure the female is well-fed before pairing to minimize defensive responses. Slightly increasing humidity before introduction may help encourage receptivity.

Mating Process

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

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

• If receptive, the female will either 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 C. marshalli females are extremely defensive and will often attack the male if left unsupervised.

Egg Sac Production

• If fertilized, the female will begin producing an egg sac 4–6 weeks after mating, which is quicker than many species.

• Maintain temperatures around 75–82°F (24–28°C) with humidity levels of 60–70%, ensuring proper ventilation to prevent mold.

• The egg sac typically contains 100–300 eggs, making it one of the more productive fossorial species.

Egg Sac Handling (Optional)

• Some breeders choose to pull the egg sac after 30–40 days for artificial incubation.

• If left with the mother, 1st instar spiderlings will emerge in 6–8 weeks, molting into 2nd instar within 3–4 weeks.

Raising Spiderlings

• C. marshalli spiderlings are fast-growing and hardy, making them relatively easy to raise.

• Provide deep substrate for burrowing, along with a secure hide to encourage natural behaviors.

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

Challenges & Considerations

• Extreme defensiveness: C. marshalli females are highly defensive, making mating risky for the male. Quick removal post-mating is critical.

• Fast growth rate: This species matures quickly, which is beneficial for breeding projects but requires timely pairings before males expire.

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

With their impressive straight-horned carapace and bold personality, Ceratogyrus marshalli is a standout species in the hobby. By prioritizing captive breeding efforts, we can help protect wild populations while ensuring that keepers have access to well-adjusted, healthy specimens. Every successful breeding project strengthens the future of this fascinating tarantula and promotes ethical, sustainable keeping practices.

Final Thoughts

Ceratogyrus marshalli is one of the most recognizable fossorial tarantulas due to its prominent straight foveal horn. While not the most colorful species, its unique appearance, impressive burrowing behavior, and voracious feeding response make it an exciting addition to any collection. However, its defensive nature and potent venom make it unsuitable for beginners.

Compared to C. darlingi, which has a rearward-curving horn, C. marshalli’s straight horn gives it an even more striking look. Both species share similar burrowing behaviors and defensive tendencies, though C. marshalli tends to be more confrontational when disturbed.

For keepers looking for a distinctive African fossorial species that embodies the classic “pet hole” experience with occasional bold feeding displays, C. marshalli is an excellent choice.

Additional Recommendations

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