Orange Baboon Tarantula, OBT, Mombasa Golden Starburst, Usambara Orange Baboon, Orange Bitey Thing
Pterinochilus murinus
Theraphosidae (Tarantulas), Order Araneae. Characterized by dense urticating-hairless bodies and heavy build.
Physical Description
A robust, medium-sized tarantula with a heavily sclerotized exoskeleton. The body is covered in dense, sensory setae (hairs). From the image, the cephalothorax is broad and the abdomen appears rounded. They lack the urticating hairs found in New World tarantulas, relying instead on speed and venom.
Size Estimate
Adult body length is approximately 4-6 cm, with a total leg span reaching 10-15 cm (4-6 inches). This specimen looks to be a sub-adult or adult based on the leg thickness.
Coloration & Markings
Bright orange to golden-yellow overall coloration (likely the RCF or 'Red Color Form'). A distinct starburst pattern is typically visible on the carapace (cephalothorax), with small black dots or 'chevrons' visible on the abdomen in better lighting.
Web Type
Extensive heavy silken tube webs and sheeting. This species is a prolific webber, often encasing its entire habitat in thick, white silk for security and vibration detection.
Eye Arrangement
Small ocular tubercle located at the front of the carapace containing eight eyes in a tight cluster; however, they rely more on substrate vibrations and wind currents than vision.
Leg Characteristics
Thick, powerful legs with darker 'socks' or tarsal tips. The legs are covered in stiff setae. They possess double claws at the tips and specialized pads (scopulae) for climbing smooth surfaces.
Venom & Safety Information
Venom Information
Neurotoxic venom that is significantly more potent than most common pet spiders. Bites cause intense localized pain, swelling, muscle cramping, and potentially systemic effects like racing heart or dizziness.
Medical Significance
Medically significant but not considered lethal to healthy humans. Symptoms include extreme pain and muscle spasms that can last for days. No antivenom exists; treatment is symptomatic (pain relief/muscle relaxants).
Safety Recommendations
Never attempt to handle this spider. Use long tongs for maintenance in enclosures. If one is found, use a 'cup and card' method with extreme caution, as they are faster than most expect. Seek medical help for bite-induced heart palpitations.
Habitat & Behavior
Habitat & Range
Native to Central, Southern, and Eastern Africa (including Kenya, Tanzania, and Zimbabwe). They are found in scrublands, dry forests, and rocky areas.
Behavior & Temperament
Infamous for a highly defensive temperament. When threatened, they often perform a 'threat posture' (rearing up and slapping). They are exceptionally fast and prone to biting if cornered rather than fleeing.
Diet & Prey
Opportunistic carnivores. In the wild, they eat insects (crickets, roaches, grasshoppers), other arachnids, and occasionally small lizards or mice. They hunt via ambush from their silken retreats.
Seasonal Activity
Active year-round in tropical climates, with activity peaks often aligning with the rainy season when prey is more abundant and males wander to find mates.
Description
The Orange Baboon Tarantula is a striking but formidable Old World species. Known for its vibrant sunset coloration and defensive nature, it is a favorite among experienced tarantula keepers but is not recommended for beginners.
Key Features
Bright orange coloration, starburst pattern on the carapace, heavy silken webbing, and the absence of urticating hairs (only found on New World species).
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 can live up to 12-15 years; males have much shorter lifespans (3-4 years). They produce 75-150 eggs in a silken sac. Spiderlings are very mobile and grow rapidly with frequent molts.
Ecological Importance
Acts as an apex invertebrate predator in its native scrublands, effectively controlling populations of herbivorous insects and smaller arachnids.
Conservation Status
Not currently evaluated by the IUCN. Generally common in its range, though habitat destruction can impact local populations.
Interesting Facts
Its nickname 'OBT' officially stands for Orange Baboon Tarantula, but keepers jokingly call it the 'Orange Bitey Thing' due to its extreme defensiveness. It is an Old World species, meaning it lacks the defensive hairs of Americas-based spiders.
Photography Tips
Shoot through clear enclosures if possible to avoid escapes. Use a macro lens from a distance to capture the starburst pattern on the head. Avoid using high-intensity flashes as it may trigger a defensive response.
Identified: 2026-07-06T20:46:36.563448