Questo è probabilmente il ragno più veloce del mondo.

A research team has identified what could be the fastest spider on Earth, according to findings published on the pre-print platform BioRxiv. The Australian giant crab spider, Heteropoda jugulans, was found to reach speeds of up to 13 kilometers per hour, surpassing the current record holder, the Moroccan flic-flac spider (Cebrenya paykullii). This discovery comes after scientists measured the speeds of over 250 spider species from around 60 families, including many from Europe, North America, and Australia. The study, led by researchers from Imperial College London and the University of Greifswald, compared the movement patterns of spiders using high-speed cameras. The team triggered escape responses in the arachnids by gently stimulating their hind legs with a brush, capturing footage of their movements. Among all the species tested, Heteropoda jugulans achieved a peak speed of 3.59 meters per second, equivalent to 13 kilometers per hour. That is nearly double the average human walking pace. However, its average speed was recorded at just two meters per second, significantly slower than its top speed. The researchers were initially focused on understanding the biomechanics of spider locomotion rather than setting records. They noted that spiders have a unique hydraulic system in their legs, which works alongside muscle power to extend and retract their limbs. Body fluid is pumped into the legs to stretch them, while muscles pull them back. Previously, this system had been thought to hinder speed, especially in larger spiders. But the new analysis suggests otherwise. The study highlights how body size and limb proportions influence maximum speed. Heteropoda jugulans has a leg span of up to 12 centimeters, contributing to its agility. According to co-author Jonas Wolff from the University of Greifswald, the key finding was that there exists an optimal ratio of leg length to body size that allows for the highest speeds. Larger spiders did not necessarily move faster, challenging previous assumptions. Another surprising result was that not all ambush predators, such as web-spinning spiders, moved more slowly than ground hunters. Some species known for waiting in webs showed remarkable speed, suggesting that physical structure plays a greater role in movement efficiency than hunting strategy alone. Despite its impressive speed, Heteropoda jugulans is not dangerous to humans. Its venom is used primarily for subduing prey, and bites occur only in extreme situations. Even then, the effects are generally mild. The spider’s large size, comparable to an adult hand, is often mistaken for aggression, but it typically flees when threatened. The research team included scientists from Germany and the United Kingdom, building upon earlier work conducted in 2021 under the leadership of Christofer Clemente at the University of the Sunshine Coast in Queensland, Australia. Their data collection covered a wide range of environments, including urban areas near London and Greifswald, as well as remote locations in North America, Southern Europe, and Australia. The findings have yet to undergo peer review, but they provide valuable insights into spider physiology and movement mechanics. The study challenges existing notions about the relationship between spider size and speed, offering a more nuanced view of how different species adapt to their environments. In Australia, where Heteropoda jugulans is commonly found, the spider occasionally enters homes, causing alarm among residents. Despite its intimidating appearance, it poses little threat to humans. Researchers emphasize that the spider's speed and size are more notable than its danger, making it a fascinating subject for further study. The results suggest that future research should explore the biomechanical advantages of specific body structures in spiders, potentially leading to applications in robotics or materials science. Scientists plan to continue investigating other species to refine their understanding of arachnid movement and behavior.