The Iranian spider-tailed horned viper, a rare snake endemic to western Iran, hunts by holding its body completely still while twitching its tail. Its body camouflages among the rocks of its semi-arid Zagros Mountains habitat, but its bulbous tail with accompanying leg-like scales looks remarkably like a large chunky spider. The snake, Pseudocerastes urarachnoides, uses its spider tail to lure unsuspecting mammals and birds to their last meal. Scans of a specimen collected in 1968 and kept in the Field Museum of Natural History in Illinois, United States, now reveal what the lure is made of. “The tip actually consists of enlarged, elongated and modified scales, which are unique among all living reptiles,” lead author Georgios Georgalis, an associate professor at the Polish Academy of Sciences’ Institute of Systematics and Evolution of Animals in Kraków, Poland, told Mongabay by email. The scanned P. urarachnoides specimen. Image © Georgalis et al. (2026). Vipers have attracted the interest of researchers for centuries, Georgalis said, but knowledge of the group’s morphology is still limited. Scientists described P. urarachnoides for science in 2006, but only this year did they publish a high-resolution 3D scan to see the mechanism inside the snake’s tail as part of a scientific study. The tail filaments, the authors said, loosely resemble those found on some ornithodiran archosaurs and other forms from the Triassic and Jurassic periods. This doesn’t mean that they are related, it’s more likely a case of convergent evolution: similar environmental demands pushing the evolutionary development of similar characteristics.…This article was originally published on Mongabay

The Klamath River in the U.S. was heavily dammed over the 20th century, blocking spawning Chinook salmon. As a result, the population of salmon that spawned in the river, which runs through Southern Oregon and Northern California, declined by roughly 90%. However, a recent study found that removing the dams resulted in a quick return of the fish to the river. In 2024, four dams were removed from the Klamath, allowing Chinook salmon (Oncorhynchus tshawytscha) to recolonize habitat that had been unavailable to them for roughly a century. Shortly after the dams were removed, 7,742 Chinook salmon migrated up the Klamath River past the former dams. In 2025, that number jumped to more than 13,000. The fish expanded into 345 kilometers (214 miles) of formerly blocked river, recolonizing 88% of their known historical habitat, the study found. First author of the study Damon Goodman told Mongabay in an email that they expected the Chinook to return to the river but didn’t know how long it would take. “What surprised us was the speed and scale of their response – it felt like we were running to keep up with the fish! These fish navigated challenging rapids, engineered fishways, and a large lake to reach habitats that had been inaccessible for more than a century.” Goodman and colleagues employed a specialized underwater sonar camera that uses sound waves instead of light to produce moving images of fish swimming through the river. “Think of it as an underwater video camera that can…This article was originally published on Mongabay