Buzz
Having grown up in a place where the scariest creature I might encounter is an earwig (Seriously, why do they always lurk in the vegetable patch?!), I’m always caught off guard by the incredible variety of insects, bugs, and other invertebrates I encounter when traveling abroad. In Britain, I’ve always thought of invertebrates as small and relatively harmless, but as you dig deeper into biology, you realize how far from the truth that idea is. This list is quite subjective, as what I find ‘unnerving’ might not be the same for everyone, but I hope some of these creatures will surprise you. Below, you'll find the top ten invertebrates that are unexpectedly large and astonishing.
10. The Giant Isopod
What really gives me the chills about the giant isopod is how much it resembles the common woodlouse, a close relative. Found in the depths of the ocean between 200 and 2000 meters, the giant isopod is a scavenger that roams the ocean floor. While the common woodlouse only grows to about 1 or 2 cm, the giant version can stretch up to 60 cm. Several species of giant isopod, all under the genus Bathynomus, exist worldwide, but they all look nearly identical. These creatures are believed to have evolved around 160 million years ago and have barely changed since, perfectly suited to their scavenging lifestyle. The good news is that despite their eerie appearance, giant isopods pose no danger to humans. They're not exactly crowd-pleasers in aquariums either, since they are slow-moving and mostly just shuffle around in search of food.
9. Japanese Spider Crab
The Japanese spider crab, Macrocheira kaempferi, holds the record for the longest leg span of any arthropod. While the largest American lobsters can match the Japanese spider crab's weight, they can't come close to its leg span, which can stretch up to 5.8 meters. This omnivorous crab will feast on anything within reach of its long, clawed limbs. There’s some debate about why they evolved such awkwardly long legs, though one theory suggests that they allow the crabs to outpace their prey. Although many reports claim these crabs have been seen on land, there’s no credible evidence to support this, and it seems unlikely they'd be able to hold themselves up out of water.
8. Giant Weta
The giant weta, Deinacrida heteracantha, found on Little Barrier Island in New Zealand, holds the title of the heaviest insect species in the world. Despite its name, which means 'terrible grasshopper,' the giant weta hardly resembles a grasshopper. The largest known specimen weighed 71 grams and could stretch over eight inches in length. This phenomenon, known as island gigantism, occurs because the weta has evolved to occupy ecological roles typically taken by small land mammals elsewhere. Although these insects mainly feed on plants, their strong mandibles can cause a painful bite, though such incidents are rare. D. heteracantha is now only found on Little Barrier Island, while other weta species remain common throughout New Zealand. Peter Jackson, the filmmaker, named his special effects company 'Weta,' and in his film *King Kong*, giant predatory weta appear as menacing creatures in a ravine.
7. Locusts
Locusts are simply giant grasshoppers, with no true distinction between them other than their ability to swarm and their larger size. While this may seem biased from a British perspective, as locusts are more familiar to other parts of the world, they are certainly larger than one might expect. I personally studied locusts and their jumping mechanisms, and I can say they are unsettling creatures. Their flight produces a loud buzzing sound, and their feet, when they land on fabric, grip tightly, making it difficult to shake them off. Being caught in a swarm of locusts would undoubtedly be a troubling experience. These swarms can contain billions of locusts, which can consume vast amounts of crops in a very short time.
6. Lion’s Mane Jellyfish
The lion's mane jellyfish, Cyanea capillata, is sometimes regarded as the longest animal on Earth, with the largest specimen ever recorded measuring 37 meters from the bell to the tip of the tentacles. The bell itself can grow up to 2 meters across. These jellyfish use their long tentacles to capture tiny floating organisms, but they also provide shelter for small shrimp that take refuge within them. While their sting causes only mild discomfort to humans, the sheer length of their tentacles can catch swimmers off guard. Treatment with vinegar can ease the pain, although it’s typically not necessary. As they grow larger, these jellyfish darken in color, with the biggest individuals appearing deep, blood-red. Like all jellyfish, they primarily drift with ocean currents, only able to pulse gently to remain near the water's surface.
5. Goliath Bird-eating Spider
The goliath bird-eater, the heaviest spider species known, can reach a weight of up to 180 grams. With a leg span of 12 inches, it was once the largest spider in the world until a giant huntsman spider was found in Laos in 2008. However, the goliath, *Theraphosa blondi*, remains much more common and is even kept as an exotic pet. The name ‘bird-eater’ comes from its occasional hunting of small birds, although it mostly feeds on insects. Despite its size, its venom, like other tarantulas, is not dangerous to humans, though its bite can still be painful. When threatened, the goliath can create a hissing sound by rubbing its legs together, which may also release tiny barbed hairs that can cause irritation. While I enjoy unique pets, I’m not sure I’d want one as large and covered in irritating hairs that could cover my face.
4. Giant Sea Spider
Sea spiders, known scientifically as Pantopoda (meaning ‘all-legs’ in Greek), are a somewhat obscure group of organisms. The giant sea spider, *Colossendeis colossea*, is the largest member of this fascinating group, growing up to about a foot in length. Despite their appearance, they are not true spiders, although they are more closely related to them than to any other type of arthropod. Their bodies are so tiny that many of their organs, including the gonads, are located within their long legs. Their intestinal tract often extends into blind pouches within the legs, where digestion occurs. The giant sea spider primarily feeds on cnidarians such as jellyfish and anemones by using a piercing proboscis to suck out their internal contents. This might be the most alien-like invertebrate on the list.
3. Colossal squid
What’s larger than a giant squid? The colossal squid is now considered the heaviest cephalopod and holds the title of the largest invertebrate ever recorded. For many years, tales of giant squids were thought to be nothing more than myths, no more real than stories of mermaids. Today, however, we have several confirmed specimens of both the giant squid and the colossal squid. At the National New Zealand Museum in Wellington, a 10-meter-long specimen is on display, caught in the Antarctic Ocean by fishermen in 2007. Research on these creatures suggests that the colossal squid hunts by ambush, using bioluminescence to attract its prey. The large specimen in New Zealand may not even be the largest one found, as much larger beaks have been discovered in the stomachs of sperm whales, suggesting that the colossal squid can grow much bigger than this one.
2. Giant Centipede
The Amazonian giant centipede, *Scolopendra gigantea*, is the first invertebrate on this list that can pose a threat to humans. Native to northern South America and various islands, this centipede can grow up to a foot long. It feeds on a variety of prey, including insects, spiders, lizards, frogs, birds, mice, and even bats. There's something unnerving about an invertebrate hunting vertebrates. This species is fast-moving and unafraid of humans. While its bite is intensely painful, it rarely proves fatal. Treatment typically involves pain management, a tetanus shot, and antibiotics to prevent infection. I’m already uneasy around small centipedes, so the thought of encountering one this large is truly nightmarish.
1. Asian Giant Hornet
The Asian giant hornet is by far the most terrifying insect I’ve encountered. *Vespa mandarin*, also known as the giant hornet, holds the title of the deadliest animal in Japan. Its sting can be fatal even to those who aren’t allergic, though it typically takes multiple stings to do so. Each sting is incredibly painful. With a length of nearly two inches, these hornets can be intimidating when they hover near your face, as I learned the hard way during a picnic. The hornet is a predator of other insects, particularly bees, and can annihilate an entire hive by using its strong mandibles to crush the bees before feeding on the honey and carrying bee abdomens back to its larvae. However, Japanese honey bees have developed a unique defense mechanism. When they detect a hornet, they swarm it, surrounding it with their bodies and rapidly contracting their flight muscles. This intense activity generates enough heat and carbon dioxide to kill the hornet.
