Giant Funnel-web Spider, Japanese Funnel-web Spider, Okinawa Funnel-web Spider
Macrothele gigas
Macrothelidae (Funnel-web Spiders), Order Araneae. Characterized by long, prominent spinnerets and impressive size.
Physical Description
A large, robust mygalomorph spider. It features a glossy black or deep brown cephalothorax and a velvet-textured, slightly hairy abdomen. The chelicerae (fangs) are powerful and strike downwards (orthognath). It possesses long, finger-like posterior spinnerets adapted for weaving dense silk.
Size Estimate
Body length typically ranges from 25 to 45mm. The leg span can reach up to 100-120mm in large adult females. This specimen appears to be an adult.
Coloration & Markings
Predominantly dark brown to jet black. The cephalothorax often has a sleek, metallic or obsidian sheen. The abdomen is typically a matte dark brown, sometimes showing a lighter, yellowish or golden hue due to fine hairs (setae) as seen in this specimen.
Web Type
Builds an extensive, dense funnel-shaped web. The web is non-sticky but extremely tough, usually constructed in rock crevices, tree roots, or embankments, with a retreat at the back.
Eye Arrangement
8 eyes grouped closely together on a small tubercle at the front of the cephalothorax, typical of mygalomorphs, providing basic light and motion detection.
Leg Characteristics
Thick, powerful legs designed for bursts of speed. They are covered in fine sensory hairs and lack the intricate banding patterns of arboreal spiders, appearing uniform dark brown or black.
Venom & Safety Information
Venom Information
Possesses potent neurotoxic venom. While not as famous as the Australian Funnel-web (Atrax), Macrothele venom contains toxins that affect the nervous system and can cause significant systemic distress.
Medical Significance
Medically significant. Bites are extremely painful due to large fangs and can cause symptoms like nausea, sweating, and muscle tremors. While no human fatalities are recorded, medical attention should be sought immediately.
Safety Recommendations
Do not attempt to handle this spider. If found in a home, use the 'container and cardboard' method for relocation while wearing gloves, or contact a professional. Treat any bite as a medical emergency.
Habitat & Behavior
Habitat & Range
Primarily found in East Asia, specifically Japan (Ryukyu Islands/Okinawa) and Taiwan. They prefer humid, subtropical forests, staying close to the ground in moist soil or leaf litter.
Behavior & Temperament
Highly defensive and aggressive if disturbed. They often rear up into a threat posture, exposing their fangs. They are primarily nocturnal ambush predators that wait at the mouth of their funnel web.
Diet & Prey
Primary diet consists of large insects such as cockroaches, crickets, and beetles. Due to their size, they are capable of taking down small vertebrates like lizards or frogs.
Seasonal Activity
Active year-round in their subtropical range, but most visible during the rainy season and summer months when males wander in search of mates.
Description
Macrothele gigas is a formidable representative of the Asian mygalomorphs. Cloaked in dark, velvet tones, it is a master of the forest floor, constructing architectural silk funnels that act as vibration-sensitive traps for passing prey.
Key Features
Large size, orthognath fangs, exceptionally long posterior spinnerets, and a glossy cephalothorax paired with a hairy abdomen.
Similar Species
Often confused with Calisoga (False Tarantulas) or other Macrothele species like M. raveni. It is distinguished from Australian funnel-webs (Atrax/Hadronyche) primarily by its geographic location and specific spinneret length.
Life Cycle
Females can live for many years (documented over 10). They produce thick silk egg sacs kept within the funnel retreat. Spiderlings stay with the mother for a short period before dispersing.
Ecological Importance
Acts as an apex invertebrate predator in its microhabitat, providing essential population control for forest-dwelling insects.
Conservation Status
Not currently listed by the IUCN, but local populations are threatened by habitat destruction and urban development in Okinawa and Taiwan.
Interesting Facts
Unlike many spiders that avoid water, their webs are often found in very damp environments. They are among the largest 'true' funnel-web spiders in the world outside of Australia.
Photography Tips
Focus on the spinnerets and the head area (chelicerae). Use a macro lens from a safe distance; a flash helps highlight the glossy texture of the cephalothorax against the matte abdomen.
Identified: 2026-07-09T18:53:02.080740