Pterinochilus murinus Care Guide: OCF, RCF, BCF and DCF — The Complete OBT Setup (2026)

Pterinochilus murinus — the Orange Baboon Tarantula, universally known in the hobby as the OBT — is one of the most widely kept Old World terrestrials and one of the most reliably defensive tarantulas you will encounter. Native to a broad range across eastern and southern Africa, this compact, fast-moving species builds elaborate silk tube systems, feeds aggressively, and will strike at perceived threats with very little provocation. Four distinct color forms exist: OCF (Orange Color Form), RCF (Rufescens Color Form), BCF (Brown Color Form), and DCF (Dwarf Color Form). Care requirements are nearly identical across all four. What differs is coloration, origin locality, and to a minor degree, adult size in the DCF.

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The Four Color Forms of Pterinochilus murinus

The designation of color forms in P. murinus reflects genuine locality and morphological variation across the species' wide African range. It is not purely a collector distinction — OCF and RCF specimens from different localities look noticeably different and were collected from different regions. Care is the same for all four.

Form	Appearance	Origin	Notes
OCF	Vivid orange with boldly striped abdomen	Usambara region, Tanzania	Most visually striking form; what most hobbyists picture when they hear "OBT"
RCF	Burnt orange to rufescent brown	Widespread across range	Most common form in the hobby; quintessential OBT coloration
BCF	Brown with warm orange tones	Southern Africa	Less common in trade; care identical to OCF/RCF
DCF	Smaller; brownish-orange	Specific southern African localities	Stays smaller than other forms at maturity; same care requirements

Species Overview and Natural Habitat

P. murinus occupies one of the widest ranges of any tarantula species, found across Angola, Zambia, Zimbabwe, Tanzania, and South Africa. In the wild it inhabits dry savanna, rocky scrubland, and open woodland — building silk-lined tube retreats under rocks, in root systems, or directly in the soil. These retreat systems are maintained and expanded over years. The spider ambushes prey from the tube entrance and retreats instantly when threatened.

This origin across dry African landscapes sets the baseline for care: low humidity, dry substrate, a permanent burrow or hide, and good cross-ventilation. The species name "murinus" (meaning mouse-grey) is something of a misnomer given how vivid the OCF coloration is — the name predates the recognition of distinct color forms.

The OBT nickname, standing for both "Orange Baboon Tarantula" and the less polite "Orange Bitey Thing," captures two accurate truths: it is a visually striking species, and it will bite. The alternative nickname "Pterror" makes the same point. The reputation is well-earned. This is not a species that tolerates being unsettled, and unlike many defensive tarantulas that posture or retreat before striking, P. murinus frequently skips both steps.

Is Pterinochilus murinus Right for You?

What Enclosure Does Pterinochilus murinus Need?

P. murinus is primarily terrestrial but highly active. Adults construct elaborate silk tube systems throughout the enclosure — given enough substrate and a hide, they will web the entire space into a functional retreat. Width and floor space matter. The enclosure does not need to be tall, but it does need a very secure lid. P. murinus actively tests enclosure edges and will find any gap.

Stage	Minimum enclosure	Notes
Sling (under 1")	6–8 oz deli cup	Cross-ventilated, dry substrate, damp corner
Juvenile (1–3")	4"W x 4"D x 6"H	2–3" substrate; small cork hide; webbing will fill enclosure
Sub-adult (3–4")	8"W x 8"D x 8"H	3–4" substrate; full cork hide; secure lid critical
Adult (4"+)	12"W x 12"D x 10"H	4–5" substrate; deep hide; expect full-enclosure web system

How to Set Up a Pterinochilus murinus Enclosure (Step by Step)

1. Use dry substrate: coco fibre and organic topsoil mix at 60/40. The substrate should be dry throughout except for one lightly moistened bottom corner. No standing moisture at the surface.
2. Add 4–5 inches of substrate for adults. P. murinus may burrow, may not — it depends on the individual. Substrate depth supports both options and allows the tube web to anchor at depth.
3. Place a cork tube or half-log hide against one wall, partially buried. The spider will use this as the anchor point for its web system and primary retreat. Do not rearrange this once established.
4. Add a shallow water dish near the hide. Change weekly. Keep it on the dry side of the enclosure, not under the hide.
5. Verify the lid is secure before introducing the spider. A binder clip on each side of a mesh lid is standard practice. P. murinus will push against a loose lid consistently until it finds a gap.
6. Introduce the spider and leave it alone. It will web within 24–48 hours and establish its tube system within the first week. Do not rearrange the enclosure once the spider has established its web.

Temperature and Humidity for Pterinochilus murinus

P. murinus originates from dry African savannas and scrubland. It is a dry-climate species. The most common care mistake with P. murinus is keeping it too moist — sustained high humidity causes respiratory stress and substrate mould in a species adapted to arid conditions.

Parameter	Ideal	Acceptable	Avoid
Daytime temperature	75–85°F (24–29°C)	70–88°F	Below 65°F / above 90°F
Night temperature	70–78°F (21–26°C)	68–80°F	Sustained below 65°F
Ambient humidity	40–60% RH	35–65% RH	Above 70% sustained
Substrate surface	Dry to the touch	Barely dry	Damp or moist surface
Misting frequency	One corner every 2–3 weeks	When water dish runs dry	Regular whole-enclosure misting

How to Feed Pterinochilus murinus

P. murinus is an aggressive, reliable feeder. It will typically strike at prey from the tube entrance or rush out to take it. Always use long tongs — this species strikes at movement, and fingers in or near the enclosure during feeding are a serious bite risk. Pre-killed prey is safer for slings. Adults will take live prey confidently. Remove uneaten prey within 24 hours.

Stage	Prey item	Frequency
Sling	Fruit flies, pinhead crickets (pre-killed)	Every 4–5 days
Juvenile	Small crickets, small dubia roaches	Every 5–7 days
Sub-adult	Medium crickets, medium dubia	Every 7–10 days
Adult	Adult dubia roaches, adult crickets	Every 10–14 days
Pre-molt / Post-molt	None — remove all prey immediately	Resume 14+ days post-molt

Watering Pterinochilus murinus

A shallow water dish should be available at all times. Change weekly. P. murinus drinks, particularly in the first 24 hours after a molt. The water dish will often get incorporated into the web system — that is normal. Access it for cleaning with long tongs, not fingers. In addition to the water dish, lightly moisten one substrate corner every 2–3 weeks to maintain moisture availability at depth without raising surface humidity.

Sling and Juvenile Pterinochilus murinus Care

Slings are defensive from the moment they are born — do not be surprised if a 1/4" sling tries to bite tongs during a deli cup change. Use forceps or tongs for all interactions from day one. Cross-ventilated deli cup with dry substrate and a pre-moistened bottom corner. Offer pre-killed prey every 4–5 days. Growth rate is moderate — P. murinus grows faster than some Old World species but slower than New World prolific growers like Psalmopoeus. Slings web actively from the first week and will establish small tube systems in the deli cup.

Molting — What to Expect

Pre-molt signs: prey refusal lasting several weeks, abdomen darkening, heavy silking of the burrow or tube entrance, sometimes completely sealing the hide with thick silk.

During molt: do not open the enclosure under any circumstances. Remove all live prey from the water dish area if accessible. P. murinus molts inside its tube system and may not be visible during the process at all.

Post-molt: wait at least 14 days before offering any food. The fangs of an Old World species require full hardening before feeding resumes. The spider will begin to expand its web again before it is ready to feed — web activity resuming is not a signal that feeding can start.

Handling and Temperament — Safety First

Despite the significant hazard profile, P. murinus is a deeply rewarding keeper species for experienced hobbyists. Its web behavior is impressive to observe, its feeding response is dramatic, and the OCF coloration in particular is genuinely extraordinary. The key is respecting what the animal actually is and maintaining consistent safe handling practices on every single interaction.

Common Health Problems

Issue	Signs	Action
Dehydration	Shrunken, wrinkled abdomen	Refill water dish; moist one substrate corner
Humidity stress	Lethargy, mould in web, surface wandering	Improve ventilation; let substrate dry out fully
Dysecdysis	Incomplete shed, stuck exuviae	Lightly mist one corner; do not force
Extended prey refusal	Weeks-long refusal with plump abdomen	Normal pre-molt behavior; check temperature
Escape attempt	Spider at lid edges repeatedly	Secure lid with binder clips immediately

Frequently Asked Questions About Pterinochilus murinus

What does OBT stand for?

OBT stands for "Orange Baboon Tarantula" — and also, colloquially, "Orange Bitey Thing." Both names are accurate. The abbreviation emerged in online hobby communities and stuck because it captures both the species' appearance and its temperament in three letters.

Which color form should I get — OCF or RCF?

The OCF (from the Usambara region of Tanzania) is more visually striking — vivid orange with bold striping. The RCF is slightly more muted in color but widely considered the "classic" OBT look and is more commonly available. Both have identical care requirements and identical temperament. Get whichever is available to you or whichever coloration you prefer. Do not choose based on assumptions about temperament — all forms are equally defensive.

Can Pterinochilus murinus be handled?

No. This is one of the few tarantulas where the recommendation is absolute rather than situational. P. murinus moves faster than most keepers can react to, strikes without warning, and has medically significant Old World venom. There are no urticating hairs to provide a warning signal before a bite. The risk-to-reward ratio of attempting to handle this species is not acceptable.

Is Pterinochilus murinus a good display tarantula?

Yes, actually — with some caveats. Once established in its enclosure, P. murinus is often visible at the tube entrance in the evening and during feeding. Its web system is impressive and worth observing. The OCF coloration is spectacular when the spider is visible. The caveat is that heavy webbing can reduce visibility significantly over time as the spider layers silk across the front of the enclosure.

How fast does Pterinochilus murinus grow?

Moderate growth rate for an Old World species. Expect 12–18 months from a 1/4" sling to 2 inches under optimal conditions (76–82°F, feeding every 5–7 days). Adults are reached at 3–5 years depending on sex — males mature faster and die significantly sooner than females.

Does Pterinochilus murinus burrow or web?

Both. P. murinus builds elaborate silk tube and funnel web systems throughout the enclosure, anchored to the hide and substrate surface. It may or may not excavate under the substrate — that depends on the individual and enclosure setup. The defining behavior is the heavy webbing, which distinguishes it visually from most other terrestrials in the hobby.

↓ Download the Free Pterinochilus murinus Care Sheet (PDF)

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Written by FLPD · Updated June 2026. For informational use only. Verify local legality before acquiring. Not CITES listed.