Orange Baboon Spider, OBT (Orange Bitey Thing), Mombasa Golden Starburst, Usambara Starburst Spider
Pterinochilus murinus
Theraphosidae (Tarantulas), Order Araneae. Key features: Mygalomorph (downward-facing fangs) and thick, sclerotized bodies.
Physical Description
A medium-sized tarantula with a robust, heavily sclerotized body. It is covered in dense, fuzzy setae (hairs) and has a distinct starburst pattern on its cephalothorax. The abdomen is oval and lacks urticating hairs, unlike New World tarantulas.
Size Estimate
The specimen appears to be a juvenile to sub-adult based on its size relative to the enclosure. Adults reach a body length of 2 inches (5 cm) and a leg span of 4 to 6 inches (10-15 cm).
Coloration & Markings
Displaying the 'UMV' (Usambara Mountain Variant) characteristic vivid orange-red or golden-yellow coloration. It features a dark radiating 'starburst' pattern on the carapace and a series of dark pits and chevrons on the abdomen.
Web Type
Not a traditional orb weaver; it produces prolific amounts of thick, opaque silk. In captivity and the wild, it creates extensive tunnel systems or sheet-like retreats that line its burrow or shelter.
Eye Arrangement
Small eye tubercle located at the front-center of the carapace containing eight eyes clustered closely together, typical of the Theraphosidae family.
Leg Characteristics
Thick, powerful legs covered in long, sensitive setae. They lack leg bands but have darker rings at the joints. The legs are designed for explosive speed rather than long-distance travel.
Venom & Safety Information
Venom Information
Possesses medically significant cytotoxic and neurotoxic venom. While rarely life-threatening to healthy adults, the venom is much more potent than that of New World tarantulas, causing intense localized pain.
Medical Significance
Moderate to High. Bites result in extreme pain, swelling, muscle cramping, and potentially systemic effects such as nausea or fever. Seek medical attention if breathing is affected or if symptoms are severe.
Safety Recommendations
Never handle this species. Use long tongs for maintenance. If relocation is necessary, use the 'cup and cardboard' method with extreme caution. Bites should be treated with ice and elevation; monitor for allergic reactions.
Habitat & Behavior
Habitat & Range
Native to Central, Southern, and Eastern Africa (including Kenya, Tanzania, and Zimbabwe). They are highly adaptable, found in scrublands, savannas, and sometimes human dwellings.
Behavior & Temperament
Renowned for a highly defensive temperament. They do not have urticating hairs, so they rely on speed and a high-potency bite. They frequently perform 'threat displays,' rising on hind legs and slapping with front legs.
Diet & Prey
Opportunistic carnivores. They eat crickets, roaches, grasshoppers, and occasionally small lizards or mice. They utilize an ambush strategy, rushing from their silk retreats to grab passing prey.
Seasonal Activity
Active year-round in tropical climates, but peak mating typically occurs during the transition between dry and rainy seasons when males wander to find females.
Description
The Orange Baboon Spider is a stunning but formidable African tarantula. Widely known in the hobby as the 'OBT,' it is cherished for its brilliant 'golden flame' coloration but respected for its lightning-fast reflexes and uncompromising defensive posture. Unlike many spiders, it is a master architect, filling its living space with intricate, beautiful white silk tunnels.
Key Features
Electric orange color, starburst pattern on the cephalothorax, 'baboon' leg pads, and the absence of urticating hairs combined with high speed and defensive behavior.
Similar Species
Pterinochilus chordatus (Kilimanjaro Mustard Baboon) which is duller/greyer, and Harpactira pulchripes (Golden Blue Leg Baboon) which has distinct blue legs.
Life Cycle
Females produce an egg sac containing 75-150 eggs within a silk hammock. Spiderlings grow rapidly due to high metabolisms. Males live 3-4 years; females can live up to 12-15 years.
Ecological Importance
Critical apex predator within the micro-ecosystem, providing natural pest control for large insect populations and serving as a food source for larger birds and mammals.
Conservation Status
Not currently listed by the IUCN. They are common in their range, though habitat destruction can impact local populations; they are also heavily traded in the exotic pet market.
Interesting Facts
The nickname 'OBT' (Orange Bitey Thing) was coined by hobbyists as a warning of their temperament. These spiders are 'Old World,' meaning they evolved in Africa/Asia and lack the defensive 'itching' hairs found on American species.
Photography Tips
Photograph through the clear enclosure with a macro lens to capture the starburst pattern. Use a soft light source to avoid glare on the plastic and reveal the fine texture of the orange setae.
Identified: 2026-07-06T20:12:01.617133