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"Spiders the size of rats" -

A recent story in The Independent newspaper reported that "giant spiders the size of rats" were making a comeback in Great Britain.

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Fen raft spider -

The spider in question is the fen raft spider. In 2010, this species of arachnid, also known as the great raft spider, was threatened with extinction, its wetland habitats in the United Kingdom largely destroyed by human activity.

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Recovery -

Fortunately, numbers have recovered sufficiently for the RSPB to announce that the spiders are set to have their best year at nature reserves run by the charity.

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Vulnerable species -

Fen raft spiders are found throughout Europe and Russia, but are still designated as Vulnerable by the International Union for Conservation of Nature (IUCN).

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Largest UK spider species -

The spiders rank among the UK's rarest invertebrates. With a span of up to three inches (eight cm), they are the largest of the UK's 660 native species of spider.

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Giant house spider -

The news sparked interest in other large species of spider found throughout the continent. Giant house spiders, for example, are among the largest spiders of Central and Northern Europe. But despite their size, the bite of this species does not pose a threat to humans or pets.

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Tarantula wolf spider -

Of even greater dimensions is the tarantula wolf spider. A large species native to southern Europe and named for the Italian city of Taranto, this spider is venomous, but its bite is not known to cause severe symptoms in humans.

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Texas tan tarantula -

Tarantulas comprise a group of large and often hairy spiders of the family Theraphosidae. Over 1,000 species have so far been identified. The Texas tan tarantula is native to southern Texas and northern Mexico. Similar to many tarantula species, the Texas tan is non-aggressive and avoids confrontations with humans and larger animals.

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Queensland whistling tarantula -

In Australia, a nation known for its collection of venomous creepy crawlies, the Queensland whistling tarantula, also known as the "barking spider," is recognized as the largest arachnid in the country. Furthermore, this one does pack a punch: its venom, while not fatal to a human, can induce a sustained session of vomiting.

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Great fishing spider -

A cousin of the aforementioned fen raft spider, the great fishing spider is another semi-aquatic arachnid perfectly happy at home on water. These spiders hunt by waiting at the edge of a pool or stream. And yes, the biggest species really are able to catch small fish.

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Hobo spider -

One of the smaller of the larger arachnids described in this gallery, the hobo spider nonetheless needs to be treated with respect. This species often builds its web in or around human habitations, and if threatened can deliver a nasty bite. It's found across Europe to Central Asia, and is also present in western North America.

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Giant jumping spider -

To clear up a slight misnomer, the giant jumping spider is actually only about one inch (2.5 cm) in length. So why is it on this list? Well, despite its diminutive proportions, this spider species can leap up to 6.3 inches (16 cm). That's nearly five time the length of its body! The tiny powerhouse is native from Sumatra to Australia, and is the largest jumping spider species known to science.

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Camel spider -

It's worth noting the scorpion-like camel spider, which confusingly is neither a spider nor a scorpion. The largest species grow to a length of between five and six inches (12–15 cm), including legs, and while frightening in appearance, the camel spider is not venomous.

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Joro-spider -

Native to East Asia, found throughout China, Japan (except Hokkaido), the Korean Peninsula, and Taiwan, the Joro-spider is a lanky member of the Nephilidae, or golden orb-weaver family of arachnids. It's venomous, but this spider's bite does not pose significant risks to humans.

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Golden silk orb-weaver -

The golden silk orb-weaver is named for the golden color of its silk. In fact, the silk thread of these spiders is among the toughest in the spider kingdom, spun to form some of the biggest webs found in the natural world.

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From spiderlings to super bugs -

So far we've highlighted some pretty big spiders, but there are larger and far more dangerous arachnids out there. So, what are some of the species that grow from tiny spiderlings (pictured) into the scariest of eight-legged critters?

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Brazilian wandering spider -

Big and bad, the Brazilian wandering spider, also appropriately called the armed spider, poses a real risk to humans. It can deliver a sufficient dose of venom to kill an adult if not treated quickly with an anti-venom. These sinister arachnids have also been called "banana spiders" due to their habit of hiding in banana shipments.

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Chaco golden knee -

One of the larger and heavier species of tarantula, the Chaco golden knee is a resident of Argentina and Paraguay. But appearances are deceptive. This handsome and hairy chap is docile by nature, characteristics that have long made it a favorite exotic pet.

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Colombian giant tarantula -

With a span of six to eight inches (15-20 cm), the Colombian giant tarantula is exactly what it says on the label. This spider is big enough and bold enough to take down small reptiles and rodents found foraging in the rainforests of Colombia and Brazil.

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Israeli desert huntsman -

A spider that can grow up to six inches (15 cm) in length, the Israeli desert huntsman is one of the largest spiders in the world. And it's fast and agile, too. It's only found in the southern Arava Valley of Israel and Jordan, on sand dunes that are fast disappearing.

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Brazilian salmon pink bird-eating tarantula -

Back in South America and not for nothing is the Brazilian salmon pink bird-eating tarantula named. This huge tarantula will take a small bird, but it's rare. Instead, it mainly feasts on large insects and, occasionally, amphibians and small reptiles.

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Brazilian giant tawny red tarantula -

Not only does the Brazilian giant tawny red tarantula impress with its size, this regal arachnid has the distinction of being one of the longest-lived tarantulas, living up to 30 years in some cases.

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King baboon spider -

Affectionately referred to as the spider monarch of Africa, the king baboon spider is enormous. Found in Tanzania and Kenya, the king baboon can reach a leg span of up to seven inches (20 cm). They are burrowing spiders and will lie in wait for a hapless beetle or even another spider to pass its subterranean bunker.

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Giant huntsman spider -

Resembling a sinewy octopus rather than a spider, the giant huntsman is the world's largest spider by leg span, which can reach up to one foot (30 cm). This species is unique to Laos and usually found lurking in caves.

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Goliath birdeater -

The largest spider in the world by mass, however, is the awesome Goliath birdeater. Found in northern South America, this humongous arachnid can boast a body length of up to five inches (13 cm) and weigh in at six ounces (175 g). Like many "bird-eating" spider species, the Goliath, in fact, rarely goes for a feathered lunch, preferring to consume large arthropods, worms, and amphibians.

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Evolution of the spider -

Before we go, let's take a quick look at how spiders evolved. They've been crawling across our planet for at least 400 million years. We know this from fossils like Attercopus fimbriungus, a spider-like creature that lived 380 million years ago during the Devonian Period, more than 150 million years before the dinosaurs.

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Trigonotarbids -

Spiders as a whole evolved from Trigonotarbids, ancient land arthropods and members of an extinct order of spider-like arachnids.

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Emergence of the spinnerets -

Major developments in spider evolution include the appearance about 250 million years ago of spinnerets (a silk-spinning organ of a spider) and silk secretion.

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Putting the world in a spin -

By the Jurassic Period, orb-weaver spiders were spinning sophisticated webs to take advantage of the abundance of a wide diversity of insect life.

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Record numbers -

Today, there are more than 45,000 known species of spiders, found in habitats all over the world, according to National Geographic. And in case you're wondering, the smallest spider on the planet is very likely the Samoan moss spider, as reports Guinness World Records. 

Sources: (RSPB) (The Independent) (IUCN) (National Geographic) (Guinness World Records) 

See also: Why spider webs are so special

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