Spiders are primarily insectivorous, but they sometimes expand their menu by hunting and eating other animals. On the other hand, there are documented cases of spider-snake fights to the death that show that both animals clash more often than it might seem. Recent research has focused on finding out to what extent spiders kill snakes and eat them, acting as their predators.
The study was carried out by Martin Nyffeler, from the University of Basel in Switzerland, and Whitfield Gibbons, from the University of Georgia in the United States.
In the research, Nyffeler and Gibbons analyzed more than 300 reports of spiders eating snakes.
It turns out that spiders eat snakes on every continent except Antarctica. 80% of the incidents studied were observed in the United States and Australia. In Europe, on the other hand, this feeding behavior of spiders has been observed on very few occasions and is limited to the consumption of small non-poisonous snakes of the blind snake family (Typhlopidae) by weaver spiders.
Analysis of the data also showed that spiders from 11 different families are capable of catching and eating snakes. “That so many different groups of spiders sometimes eat snakes is a completely novel finding,” Nyffeler emphasizes.
An immature snake caught in the web of a Latrodectus geometricus spider in a home in Georgia, USA. (Photo: Daniel R. Crook)
Certain spiders in the Theridiidae family turned out to be the successful snake hunters in nearly half of the observed incidents. Its powerful venom contains a toxin that acts specifically against the nervous system of vertebrates. These spiders build extremely tough webs, allowing them to capture larger prey such as lizards, frogs, mice, birds, and snakes.
Another finding made in the meta-analysis: spiders can defeat snakes from seven different families. They are capable of defeating snakes up to 10 and even 30 times their size.
The largest snakes captured by spiders are up to a meter in length, and the smallest only about six centimeters. According to the statistical analysis carried out by the two researchers, the average length of the snakes captured was 26 centimeters. Most of the snakes captured were very young, almost newborn animals. The fact that some spiders are able to dominate such large prey is due to their powerful neurotoxins and robust webs.
Many species of spiders that occasionally kill and eat snakes have a venom that can also be lethal to humans.
In many cases, the snakes defeated by spiders are not exactly harmless: about 30% are poisonous. In the United States and South America, spiders sometimes kill such fearsome snakes as the highly poisonous rattlesnake and coral. In Australia, brown snakes (which are among the most poisonous snakes in the world and in fact belong to the same family as cobras) are often preyed upon by the red-backed spider, closely related to the black widow.
Although the spider that kills a snake feasts, it usually does not consume more than a small part of its prey; the rest is eaten by ants, flies and others.
The study is titled “Spiders (Arachnida: Araneae) feeding on snakes (Reptilia: Squamata)”. And it has been published in the academic journal American Journal of Arachnology. (Source: NCYT from Amazings)