Orange Baboon Spider, OBT (Orange Bitey Thing), Mombasa Golden Starburst, Usambara Orange Baboon
Pterinochilus murinus
Theraphosidae (Tarantulas), Order Araneae. Subfamily Harpactirinae (Baboon Spiders)
Physical Description
A medium-sized heavy-bodied tarantula covered in thick, bristly setae (hairs). The cephalothorax features a distinct starburst pattern radiating from the fovea, while the abdomen is oval-shaped and densely hairy. Unlike New World tarantulas, they lack urticating hairs.
Size Estimate
Body length typically 4-6 cm; leg span ranges from 10-15 cm (4 to 6 inches). The specimen in the image appears to be a juvenile or sub-adult based on proportions.
Coloration & Markings
Best known for its vivid orange or golden coloration (the 'RCF' or Red Colour Form), though several color variants exist (grey, brown, olive). The dorsal side features a characteristic dark 'starburst' pattern on the carapace and a series of dark spots and chevrons on the abdomen.
Web Type
Heavy, sheet-like silk tunnels and retreats. They are prolific webbers that create complex nurseries of thick white silk incorporating substrate and moss for camouflage.
Eye Arrangement
Small ocular tubercle located at the front-center of the carapace containing eight eyes arranged in a compact group, typical of Theraphosidae.
Leg Characteristics
Thick, powerful legs designed for speed and burrowing. Covered in sensory hairs with dark tarsal claws. They typically lack the contrasting banding found in some other baboon spiders but may show faint markings on the joints.
Venom & Safety Information
Venom Information
Possesses potent medically significant venom (neurotoxic properties). While not considered lethal to healthy humans, the bite is exceptionally painful and more severe than that of most New World tarantulas.
Medical Significance
Moderate to High danger. A bite often results in intense local pain, swelling, muscle cramping, and sometimes systemic effects like nausea or dizziness. Medical attention should be sought if an allergic reaction or severe muscle spasms occur.
Safety Recommendations
This is not a 'handling' spider. Use long forceps for cage maintenance and never attempt to touch. If found in a home (as an escapee), use the 'cup and cardboard' method with extreme caution, as they are incredibly fast and can climb smooth surfaces.
Habitat & Behavior
Habitat & Range
Native to Central, East, and Southern Africa (including Angola, Burundi, Tanzania, Kenya). Found in scrublands and dry forests. They are highly adaptable, living as opportunistic burrowers or semi-arboreal residents.
Behavior & Temperament
Renowned for its extremely defensive and skittish temperament (hence the hobbyist nickname 'Orange Bitey Thing'). It does not hesitate to throw a threat posture, striking the ground or the intruder with its front legs, and is very fast.
Diet & Prey
Generalist carnivore. Preys on insects like crickets, roaches, and grasshoppers. Larger adults can occasionally take small vertebrates like lizards or pinky mice in the wild.
Seasonal Activity
Active year-round in tropical climates, with increased movement and mating activity typically following the onset of rainy seasons.
Description
The Orange Baboon Spider is a vibrant, sun-colored tarantula that stands as one of the most iconic Old World species in the arachnid world. Wrapped in its distinctive 'starburst' markings, it is a master architect, transforming its environment into a fortress of thick, crystalline silk. While visually stunning, it is a formidable predator and highly defensive, acting as a sentinel of the African shrublands.
Key Features
Vivid orange/golden hairs, black 'starburst' radial pattern on the carapace, presence of heavy silk webbing, and a lack of urticating hairs.
Similar Species
Pterinochilus chordatus (Kilimanjaro Mustard Baboon), which has more muted brown/grey tones, and Harpactira pulchripes (Golden Blue Leg Baboon), which has distinct blue legs.
Life Cycle
Females can live up to 12-15 years, while males are shorter-lived (3-4 years). After mating, females produce an egg sac containing 75-150 spiderlings. Spiderlings grow rapidly through frequent molts.
Ecological Importance
Acts as an essential apex invertebrate predator, controlling populations of various insects. It also serves as a food source for larger animals like centipedes, birds, and small mammals.
Conservation Status
Not evaluated by the IUCN. Generally considered common in its range, though local populations can be affected by the exotic pet trade and habitat loss.
Interesting Facts
Despite having no urticating hairs to flick at predators, it uses its speed and potent venom for defense. It is one of the few tarantulas that is widely distributed across a massive geographic range in Africa, leading to several distinct color variations.
Photography Tips
Photograph through the enclosure glass or from a safe distance using a macro lens. Focus on the 'starburst' pattern on the head. Avoid using high-intensity flashes which may startle the spider into a defensive strike or flight.
Identified: 2026-07-06T18:40:33.269361