Slugs: a discovery

I began my blog last week by expressing how hot it’s been. This week, some parts of the country saw a month’s worth of rain in a few days. The important thing to remember though is that there’s still plenty of wildlife to see at this time of year regardless of what the weather is doing. With the rain hammering the bathroom skylight as I got ready for bed, this friendly looking chap scaled a sheer cliff face without the need for ropes and climbing axes, or arms and legs for that matter.

I share my home with lots of different creatures – read all about it here (Photo: Sophie Lightfoot)

This intrepid climber got me thinking: I know almost nothing about slugs. I thought I’d do some investigating and share what I find out on this blog.

There are around 40 species of slug in the UK

The one I found in the bath is either a tree slug, Balkan threeband slug, or greenhouse slug – it's hard to tell when they are still juveniles apparently. In the UK, slugs range from the ashy-grey slug, up to 30 cm when fully grown and the biggest slug in the world (yes, the biggest slug in the world lives in the UK), to the relatively small common garden slug that can be up to 3 cm when fully grown.

All terrestrial slugs evolved from terrestrial snails

Instead of lugging your house around on your back, why not enclose it in your own body? While many slugs now have shells inside their bodies, some slugs – semi-slugs – have tiny shells on their backs. They kind of look like little saddles – think Tinys from the Neverending Story, zooming around on racing snails.

A slug is basically a wet foot

Imagine moving around by secreting mucus from your bare feet onto the floor, scrunching your toes up, and propelling yourself forward. Pretty elegant I’m sure you’d agree. Slugs move by creating rhythmic muscle movements on the underside of their body known as their foot. To lubricate their path, they secrete pedal mucus and just glide along. A slug can follow its mucus trail back home once it's finished its very important slug business.

Slugs can smell through their eyes

Pretty handy if you come across something that both looks horrible and smells horrible. Just shut your eyes and it’s gone! The optical tentacles at the head of the slug contain a light sensitive dot, can be regrown if lost, and provide the slug with a sense of smell. The two tentacles below are used for feeling around and taste testing. What a great system.

Slugs have massive dentistry bills

With around 27,000 tooth-like protrusions called denticles covering a tongue-like muscle called a radula, kissing a slug would be slightly uncomfortable. Fortunately a slug would never catch you during a game of kiss-chase, but I won’t be dozing off anywhere damp anytime soon.

Slugs eat, and are eaten

Most UK slugs are herbivores, chomping their way though leaves, flowers, fruits, mushrooms, lichens, and decaying plant matter. Some slugs eat carrion, and there are a few carnivorous species that hunt other slugs and snails. It’s a good thing they’re not hunting anything faster as they’d get hungry, quick. Slugs also provide food for some UK favourites: thrush species, hedgehogs, toads and some ground beetles.

Slugs like it wet, cool and foggy

Great news! If it’s sloshing it down, go on a slug hunt. If it’s too hot and dry, slugs will encase themselves in a kind of thin cocoon-like structure to maintain moisture levels, so it’s probably best to just stay in and complain.

For better or worse, I don’t think I’ll ever look at a slug in the same way again.

Jack