Unbelievable but true. There are spiders that eat snakes. Spiders are primarily insectivores, but they occasionally expand their menu by catching and eating small snakes. And observations of snake-eating spiders have been reported around the world. Two researchers from Basel and the US consolidated and analyzed over 300 reports of this unusual predation strategy!
Fun Facts: Spiders Eating Snakes
→ Spiders eat snakes on every continent except Antarctica.
→ Eighty percent of the incidents studied were observed in the US and Australia.
→ In Europe spider feeding behavior has been observed only extremely rarely (less than 1 percent of all reported incidents) and is limited to the consumption of tiny, non-venomous snakes of the blind snake family (Typhlopidae) by small web-building spiders.
→ Incidents of snake predation by spiders have never been reported from Switzerland. A possible explanation is that Switzerland’s native colubrids and vipers are too big and heavy even when freshly hatched for Swiss spiders to subdue them.
→ The data analysis showed that spiders from 11 different families are able to catch and eat snakes.
→ Black widows of the family Theridiidae were the successful snake hunters in about half of all observed incidents. Their potent venom contains a toxin that specifically targets vertebrate nervous systems. These spiders build webs composed of extremely tough silk, allowing them to capture larger prey animals like lizards, frogs, mice, birds and snakes.
→ Another new finding from the meta-analysis: spiders can subdue snakes from seven different families. They can outfight snakes 10 to 30 times their size.
→ The largest snakes caught by spiders are up to one meter in length (3 feet, 3 inches), the smallest only about six centimeters. According to the statistical analysis done by the two researchers, the average length of captured snakes was 26 centimeters. (30 centimeters = 1 foot)
→ Most of the snakes caught were very young, freshly hatched animals.
→ The fact that some spiders are able to subdue oversized prey is attributable to their highly potent neurotoxins and strong, tough webs.
→ Many spider species that occasionally kill and eat snakes have venom that can also be lethal to humans. That means the venom of various spider species has a similar effect on the nervous systems of snakes and humans.
→ The snakes captured by spiders are anything but helpless themselves: about 30 percent are venomous. In the US and South America, spiders sometimes kill highly venomous rattlesnakes and coral snakes. In Australia, brown snakes (which belong to the same family as cobras) often fall prey to redback spiders (Australian black widows).
→ When a spider catches a snake, it will often spend hours or days feasting on such a large prey. Spiders have an irregular feeding pattern. When a lot of food is available, they eat in excess, only to go hungry for long periods again afterward. They store excess food as energy reserves in their body and use it to tide them over longer periods of starvation.
→ A spider often eats only a small part of the snake it kills. Scavengers (ants, wasps, flies, molds) consume what remains.
Journal Reference: Martin Nyffeler, J. Whitfield Gibbons. Spiders (Arachnida: Araneae) feeding on snakes (Reptilia: Squamata). The Journal of Arachnology, 2021; 49 (1) DOI: 10.1636/JoA-S-20-050