In order to feed, spiders do not stop at anything. So many of them are attacked by snakes. Fascinated by this behavior, two researchers from the University of Basel (Switzerland) and Georgia (United States) identified such duels.
A varied diet
Spiders are common and abundant predators. They developed many feeding strategies, changing the prey to which they focused their gazes. They of course attack insects, but also earthworms, snails, small vertebrates (mice, birds, bats …) which sometimes even go as far as take the goldfish out of the water. For some of them, spiders do not hesitate to oppose other terrible predators: snakes. A new study published in May 2021 Journal of Arachnology aims to collect all known data on snakes that feed on snakes. Two researchers reviewed 319 such events.
Spiders that measure less than two centimeters on average
Over 30 species of spiders are known to naturally consume snakes such as the North American Black Widow (Latrodectus mactans). There are also 11 species that have adopted this behavior during the experiment or in captivity. One would think that the examples in question are particularly impressive, with helicera (poisonous, connected spider hooks) the size of a human finger. Not at all: the average size of these spiders is 1.7 centimeters. As for the target snakes, they measure an average of 26 cm. These are very often newborns or minors, light specimens.
There are 86 known species of snakes that end up on the spider menu (e.g. brown tree snakes or Boiga irregularities) and five others were already consumed in captivity or during the experiment. “Spider predation on snakes has so far been observed in 25 countries“, underscores the study. It is”a global trend occurring on all continents except Antarctica. The vast majority of reports of spider predation by snakes come from the United States (51% of all natural disasters) and Australia (29%)“.
As for the incidents studied by the authors of this new study, 87% of snakes caught by spiders were killed, and only 1.5% managed to escape on their own (about 11% of people were rescued). Black widows, for example, rely on their balls of thread and the viscosity of some of them to catch snakes. An unfortunate person who lets himself be killed is killed by a bite that delivers a powerful neurotoxin. Tarantulas also produce compounds that “effectively target the nervous system of snakes“Moreover, biologists note that they do not know.”there is no documented record in which a venomous snake captured by a spider poisoned a spider. So we don’t know if spiders are vulnerable or immune to snake venom.However, the roles are sometimes reversed: species of snakes that like arthropods readily include spiders in their diet.