How Many Spiders Are There in the World?
Spiders are considered the most successful carnivores on the planet. They consume 400 million to 800 million tons of food every year. These numbers are only a fraction of the arachnid population. But if they were to consume a person of average body mass, it would amount to more than 20 pounds of meat per day.
Spiders have a complex anatomy. Each spider has two body segments, an abdomen and a thorax. The abdomen contains the reproductive system and lungs. There is also a mouth, a labrum, and fangs.
Some spiders are predators while others are opportunists. A few larger species have been known to snack on smaller mammals and birds. However, most spiders primarily feed on insects.
Unlike other animals, spiders have a wide range of strategies for catching their prey. While most rely on a vibration to detect their prey, some spiders also use silk. This protein fiber is strong and can be used for many purposes, including climbing, tethering for safety, and weaving a web.
Scientists estimate that there are about 50,000 different species of spiders. Of these, only 30 species are considered dangerous to humans. That means there may be another 50,000 species that have not yet been discovered.
Scientists have calculated that there are approximately 840 spiders in a square meter of land. If they all weighed one pound, this would mean 3.5 million spiders on an acre of land.
The venom of some spiders can cause allergic reactions in people. Some of the most venomous spiders, such as the brown recluse spider and the southern black widow spider, are highly toxic.