As if one spider wasn't enough, some spiders do live in social groups. A group of spiders is known as a clutter or cluster.

The cheerful-looking Hawaiian happy-face spider (Theridion grallator) is in danger of extinction. Its Hawaiian name is nananana makaki'i.

Diving bell spiders (Argyroneta aquatica) are tiny, measuring just 0.4 to 0.6 inches (10 to 15 millimeters) long, so one bubble can supply more than a day's worth of air.

Long-legged nursery-web spiders have a rather unconventional mating method that could rival anything in E.L. James' bestseller Fifty Shades of Grey. Males wrap silk around a female's legs before and during the encounter. Scientists think this could be a survival tactic, because female spiders are partial to a snack after doing the deed, and unfortunately males are often the closest thing at hand.

Spiders famously dine on flies, but there are quite a few species that prefer a heftier meal, including the giant golden orb weaver, Goliath birdeater, and reddish parachute spider, all of which regularly dine on bats.

B. kiplingi, named for Bagheera the black panther from Rudyard Kipling's The Jungle Book, is notable for its peculiar diet, which is mostly herbivorous. No other species of spider has such a vegetarian diet.

The Texas brown tarantula, also known as the Oklahoma brown tarantula or Missouri tarantula (Aphonopelma hentzi), is one of the most common species of tarantula living in the Southern United States today. While males rarely live more than a few years after reaching maturity, females have been known to live up to 40 years.

All spiders have eight legs. They also possess a pair of shorter limbs called pedipalps, that in males serve as sex organs. Some spiders seem to have ten legs and not eight, because these pedipalps look like an extra pair of legs.

Using filters that sit in front of cells in their eyes, the day-hunting jumping spider (Salticidae) can see in the red spectrum, green spectrum, and in UV light.

Samoan moss spiders live on the Samoan Islands. About the size of the period at the end of this sentence (0.3 mm), they are barely visible to the human eye.