40 Fun Facts About Slugs

Which big cat names the great grey slug, which mates dangling in mid-air from a mucus thread?

Leopard slug is the common name of Limax maximus, a spotted species whose Latin name simply means 'biggest slug', though one relative grows even larger.

Slug blood carries oxygen using haemocyanin, a protein built around which metal instead of iron?

Copper sits at the heart of haemocyanin, which turns blue when it picks up oxygen and is colourless without it.

The sea slug Elysia chlorotica steals parts of the algae it eats to carry out which plant process?

Photosynthesis can carry on inside the slug for up to ten months, because it stores the algae's green chloroplasts in the cells of its own gut.

The sea slug Elysia marginata can shed its entire body and then regrow it from which surviving part?

Its head separates over several hours and then grows a whole new body, heart included, which may be a drastic way of getting rid of parasites.

Which slug-like Star Wars crime lord puts the frozen Han Solo on display in his palace?

Jabba the Hutt took shape as the first film's script was finished, when George Lucas settled on a fat, slug-like creature with a gaping mouth and eyes on feelers.

Which drink do gardeners pour into small traps as a traditional way of catching slugs?

Beer traps are a classic home remedy, though like crushed eggshells and coffee grounds they only really help in a small garden.

The blue dragon sea slug eats which venomous drifting animal and stores its stinging cells?

Portuguese man o' war stings are kept in the slug's own tissues as a defence, so anyone who picks up a blue dragon can get a very painful sting.

Centuries before it named a shell-less animal, the English word slug was an insult aimed at whom?

A lazy person was a slug in medieval English, and the slow-moving animal only picked up the name in the early 1700s.

Harvard engineers copied the defensive mucus of the dusky arion slug to make which medical product?

Surgical adhesive modelled on the slime sticks to wet tissue and can hold on to a beating heart; the slug uses its mucus to anchor itself when a predator tries to pry it loose.

In 2024 the bright yellow banana slug was named the official state slug of which US state?

California made it official when Governor Gavin Newsom signed the bill in September 2024; banana slugs live on the floor of its damp coastal redwood forests.

Salt kills a slug by drawing the water out of its body through which process?

Osmosis is deadly to an animal that is mostly water, but farmers never use the trick, because salty soil would harm their crops as well.

What does a land slug use the single round hole on the right side of its body for?

Breathing happens through this one pore, the pneumostome, which opens and closes to let air into the slug's single lung.

A slug feeds with a radula, a ribbon often compared to a tongue and covered in rows of tiny what?

Teeth made of tough chitin cover the radula, which scrapes or cuts food before it is swallowed; hunting slugs have razor-sharp ones for seizing prey.

Slugs and snails make up the gastropods, the second-largest class of animals after which group?

Insects are the only class with more species; the gastropods have an estimated 65,000 to 80,000 living ones.

Every slug has both male and female reproductive organs, which makes it what kind of animal?

A hermaphrodite slug still looks for company: two slugs circle each other and both pass sperm to the other.

A land slug's upper tentacles carry its eyespots, but which sense does the lower pair provide?

Smell is the job of the lower pair, and in most land slugs all four tentacles can be pulled back inside the body out of harm's way.

Foxes and badgers both eat slugs, and so does which small spiny mammal that forages at night?

Hedgehog diets include slugs, and so do those of toads, blackbirds, starlings and even brown trout: almost every major group of vertebrates has its slug-eaters.

Most slugs keep a remnant of a shell hidden inside the body, mainly as a store of which mineral?

Calcium salts are banked in the leftover shell, and Pliny the Elder already knew that the great grey slug carried one under its skin.

When threatened, the sea hare, a large and bulky sea slug, squirts out a cloud of which liquid?

Ink from a sea hare may be white, purple or red, depending on the seaweed it has been eating, and it dulls a predator's senses.

The fluffy-looking sea slug nicknamed the sea bunny became an online hit in 2015 in which country?

Japan fell for the sea bunny on Twitter thanks to its rabbit-like look; the 'fur' is really a coat of tiny fleshy bumps the slug uses to sense its surroundings.

Eric Kandel won a Nobel Prize for using the sea slug Aplysia to show how nerve cells store what?

Memories could be traced in Aplysia because it has only about 20,000 nerve cells, which made its simple kinds of learning far easier to follow.

The ghost slug's species name, ysbryda, comes from the word for ghost in which language?

Welsh supplied ysbryd, meaning ghost, for a white, eyeless slug that burrows deep underground and was named in 2008 by scientists from Wales's national museum and Cardiff University.

Shelled slugs of the genus Testacella live underground in rich soil, where they hunt which animals?

Earthworms are their prey, and these rarely seen hunters still carry a very small shell, set far back on the body.

Arion vulgaris, an invasive slug spreading widely since the 1950s, has which word in its nickname?

Killer slug is the popular name for this large slug, which can gather in such numbers that it becomes a serious problem for farms and gardens.

Which large, colourful sea slug flees danger by unfolding its body edges and swimming off with rippling movements?

Spanish dancer nudibranchs take their name from this escape swim, and they can grow to 25 centimetres long.

Nudibranchs are colourful sea slugs whose name joins Latin and Greek words meaning naked what?

Gills are worn on the outside by many nudibranchs, as feathery plumes arranged in a rosette on the back.

Most slugs cling on when attacked, but what does the spotted Kerry slug of Ireland do instead?

Rolls into a ball: the Kerry slug lets go of its rock or tree trunk and curls up completely, a defence found in no other member of its family.

Certain slugs can escape a predator's grip by shedding which bit of the body?

Part of the tail can be cast off, as some lizards do; the trick, called autotomy, leaves the predator holding a scrap while the rest of the slug gets away.

Eating a raw slug can pass on rat lungworm, a parasite that causes which serious illness in people?

Meningitis from rat lungworm is rare in people, but slugs and snails carry the parasite's larvae, so badly washed lettuce is a risk too.

A slug's slime trail does more than ease its way: it also helps other slugs of its species do what?

Find a partner: a slug can tell that a trail was laid by its own species and follow it, and some meat-eating slugs track their prey the same way.

A gas bubble in its stomach keeps the blue dragon sea slug afloat at the surface in which position?

Upside down is how it floats, so its blue underside faces the sky and its silvery back faces the deep, hiding it from hunters above and below.

Many nudibranch sea slugs arm themselves by eating which simple animals and storing their toxins?

Sponges supply the poisons, and nudibranchs even pass them on to their eggs to put predators off.

Shell loss arose many separate times in slugs, an example of which kind of evolution?

Convergent evolution explains why slug families look alike without being close relatives: each descends from a different line of snails.

The ash-black slug, the largest land slug in the world, is native to the woods of which continent?

Europe's ancient woodlands shelter this giant under dead leaves and logs; it can grow to more than 30 centimetres, though most adults are 10 to 20.

Slither, a horror comedy about slug-like alien parasites, was which filmmaker's directing debut?

James Gunn wrote and directed Slither and gave himself an uncredited cameo, eight years before he made Guardians of the Galaxy.

Metaldehyde, the active ingredient in many slug pellets, was first developed as which product?

Solid fuel made of metaldehyde is still sold for camping, but as slug bait it proved toxic enough for Britain to ban its outdoor use from spring 2022.

A biological treatment that gardeners water into soil to kill slugs is made of which tiny organisms?

Nematodes sold as Nemaslug seek out slugs in the soil and infect them, and because no chemical is involved the treatment suits organic growers.

Which predators get past a slug's sticky defensive mucus by first rolling the slug in dirt?

Driver ants use the dirt to soak up the mucus, a coating that is enough to put some other ant species off attacking at all.

What is the name of the saddle-shaped shield of flesh at the front of a land slug's back?

Mantle is the name, and in snails the same organ builds the shell and keeps adding to it as the animal grows.

In 2022 the Royal Horticultural Society announced it would no longer call slugs and snails what?

Pests was dropped as a label because, by the society's own count, only nine of the 44 slug species recognised in the UK eat garden plants.