Hawaii’s tropical environment supports a diverse range of arachnids, and the islands are home to several species of large spiders. While encountering a spider with a significant leg span can be startling, the vast majority of these larger species are not dangerous to humans. The perception of “big spiders” often relates to their impressive physical size, not their venom toxicity. Understanding the specific species present helps reduce anxiety and appreciate the role these animals play in the island ecosystem.
Identifying Hawaii’s Largest Spiders
The spider most responsible for the perception of “big” in Hawaii is the Giant Crab Spider, commonly known as the Cane Spider or Pantropical Huntsman Spider (Heteropoda venatoria). This non-native species is widespread across the islands. Its size is impressive due to its long, laterigrade legs, meaning its legs are splayed out sideways like a crab’s. The Cane Spider’s body length typically measures between 0.75 to 1 inch, but its leg span can reach up to 6 inches.
Another large, commonly seen arachnid is the female Golden Silk Orb-Weaver (Trichonephila species), sometimes called the Banana Spider. The female’s body can grow up to 3 inches long, and its overall leg span can approach 4 inches. These spiders are easily identified by the massive, intricate webs they weave, which are notable for their brilliant yellowish-golden silk. They are found suspended in these large, strong webs in outdoor settings.
Assessing the Medical Risk to Humans
Despite the intimidating size of the Cane Spider and the Golden Silk Orb-Weaver, neither species poses a serious medical threat to people. The Cane Spider’s bite is rare, as they are non-aggressive and prefer to flee when disturbed. Their venom is harmless to humans. Similarly, the large Golden Silk Orb-Weaver is not aggressive, and its venom is low in toxicity, causing only mild, localized pain.
The medically significant spiders in Hawaii are smaller, including the Brown Widow (Latrodectus geometricus) and the Black Widow (Latrodectus species). The Brown Widow, identifiable by its spiky egg sac and orange hourglass marking, is found throughout the islands, though its venom is less potent than that of the Black Widow. The Mediterranean Recluse (Loxosceles rufescens) is also established in Hawaii and is of medical concern. The Brown Recluse (Loxosceles reclusa) is not established on the islands.
Where Spiders Are Commonly Encountered
The largest spiders in Hawaii, like the Cane Spider, are frequently encountered in residential and urban environments because they are active hunters. They seek shelter from heat or rain and can be found indoors, sometimes hiding under furniture. Their presence inside is beneficial, as they prey on household pests like cockroaches. Outdoor encounters often occur in garages, sheds, woodpiles, or cars, as they favor dark, quiet spaces.
Conversely, the Golden Silk Orb-Weaver is seen exclusively outdoors, constructing substantial webs in forested or garden areas. Medically significant spiders, such as the Widow species, prefer low-traffic, undisturbed areas. Accidental encounters are more likely when moving stored items like old boxes or firewood. If a large spider is found indoors, capture and release using a cup and cardboard is the recommended removal strategy.