The hunting abilities of spiders are well-known, insects being their main prey. Now researchers have discovered that certain species of spiders consume tiny freshwater fish often twice the size of it.
Researchers have long known about the spiders that consume fishes but recent study showed the practice to be more common than previously thought. They found that these groups of spiders are present in every continent except Antarctica.
"Fish may represent a 'big-ticket item' in the nutritional budget of semi-aquatic spiders," said zoologist Martin Nyffeler of the University of Basel in Switzerland, who led the study.
"Fish meat is high-quality prey regarding protein content and caloric value. Feeding on fish may be particularly advantageous during the mating period when the elevated energy and protein requirements of gravid (pregnant) female spiders require increased food intake, or at times of limited availability of invertebrate prey, " Reuters quoted Nyffeler saying.
The fish eating spiders use effective enzymes and neurotoxins to kill and digest fish. Some semi-aquatic spiders are capable of swimming and can even walk on surfaces of lakes, streams, ponds or swamps.
They usually anchor their hind legs on to a surface such as plant or stone and use their front legs to trap the prey on water surface. Once the fish gets trapped, it is dragged to a dry place such as a tree trunk or a rock and start feeding on the prey.
"The findings of such a large diversity of spiders engaging in fish predation is novel. Our evidence suggests that fish might be an occasional prey item of substantial nutritional importance", said Martin Nyffeler in a statement.
It usually takes a spider many hours to consume a fish until nothing is left except for bones and scales.
Treating with fish is observed in warmer climates. According to researchers, around 18 species of spider from five families have been found consuming fish in the wild.
In the study, around 30 species of fish that ranged from an inch to 2-1/2 inches long (2 to 6 cm) were found being trapped and consumed by spiders in the wild. In North America, the spider species Dolomedes triton are repeatedly seen catching fish and the species Dolomedes facetus steals goldfish from ponds in suburban gardens in Australia.
However, fishes are not the only vertebrates that spiders consume, some have been known to feast on toads, frogs, salamanders, snakes, mice, lizards, rats, bats and birds, according to Nyffeler .
"Spiders are more adept predators than most give credit for," noted Brad Pusey of the University of Western Australia, who also worked on the study.
The details of the study was published in the scientific journal Plos One.
Check out a stunning video of a spider trapping a fish and consuming it.