Sunday, 12 April 2015

A Home on Your back - Amazing Snails and a few Slugs!

Some people think snails and slugs are a bit slimy and kids often squeal at the thought of picking one up. I have to admit I am fascinated by slugs and snails but I also have total admiration for snails as they carry their homes around on their backs all day! A snail can completely contract into its shell and hide there. The one pictured below is poking out its beady tentacle!

Common Snail - Local neighbourhood
Slugs and snails are molluscs and they form the class of Gastropods. They have some pretty amazing features such as a 'radula' which is what they use to eat. The radula is basically a long rasp which has tiny teeth like structures that slugs and snails use to munch their food. The majority of slugs land snails are herbivores, eating plant material. However snails can also be found in freshwater and marine habitats and some of these are predators and will eat anything!
Freshwater Pond Snail - Clint's Quarry
The other amazing thing about slugs and snails is their 'foot' and way slugs and snails can defy gravity and hang onto leaves and stalks without falling off! The foot is basically a large muscle and by contracting this muscle, the snail or slug is able to move along the ground. The foot also produces slime and this is what is left behind and we often see as a trial.

A slug dining in the air!
When studying for my Natural Sciences degree and in particular when learning about Evolution, I studied banded snails. Banded snails are a prime example to show what is known as polymorphism, which is basically where there are two or more different phenotypes in a population. The phenotypes are the characters that are expressed in the organism and these are influenced by both genes and the environment that the organism lives in. As a result of natural selection one of the phenotypes can become more frequent in the population than the other. There are two species of banded snails and these are brown lipped or white lipped and the snails can be banded, non-banded or many banded and it is great to study them in relation to their habitat to see if their camouflage does affect the abundance of one type over the other. Have a look at the Evolution Megalab which has loads of helpful information on looking for snails and studying them - a great fun and easy activity for all the family!

Banded white lipped snail, Cepaea hortensis - Local Neighbourhood
Non-banded white lipped snail, Cepaea hortensis

Banded white lipped snail, Cepaea hortensis - Local Neighbourhood
Other interesting things about snails in that they prefer damp conditions, so if it is too dry they will hunker down for a few days until the conditions improve for them. One day when I was out for a walk I found a whole load of snails snuggled up together in the crook of a tree!
The Snail Tree - Local Neighbourhood
So slugs and snails are actually quite interesting and fun. Next time you are out, don't ignore them and think they are slimy have a think about what amazing little creatures they are!

Sources of Information:


Evolution Megalab:

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