Fish-eating spiders

Source text and photo:, photo by Ingo Arndt
A spider web for catching insects is a common sight. But there are also spiders that go searching for their prey, even if that prey is up to five times larger and lives in the water.
A spider that catches a fish and eats it appeared to have been a special case. Since a team of Swiss and Australian researchers joined forces, however, there are now 18 spider species known to eat fish. These spiders are found on every continent except Antarctica. The spiders hunt especially in warm, oxygen-depleted bodies of water because the fish there come to the surface more often for more oxygen. A spider stands with its hind legs firmly on a stone and rests its front legs on the surface of the water, and it waits for its opportunity. The tiniest vibration is enough to make it strike. There are also spiders that can swim or dive to find their prey.

Prey animals tend to be an average of 42 times smaller than their predators — but not among spiders! They can prey upon animals up to five times their size. The spiders are well-equipped to catch fish: they have jaws that can perforate flesh and introduce powerful neurotoxins. Once the fish is dead, the spider drags it ashore, introduces enzymes to liquefy the fish flesh, and then consumes the ‘fish soup’.

The scientists got their information by searching academic and other publications, and also internet blogs. This study has been published in PLOS ONE.