Mystery collection of garden snail shells

It's not their fault they don't have feathers! Doesn't make them any less interesting. And just like the birds, it's good to know what species are about locally at any given time.

There's expertise within the club and beyond on most aspects of our local fauna. Let's tap into it.
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sburke
Posts: 158
Joined: Wed Mar 11, 2009 10:30 am
Location: Townsville Region

Mystery collection of garden snail shells

Post by sburke »

When moving some pallets at home a couple of weeks ago I found a collection of about a dozen empty garden snail shells grouped together amongst the leaves which had collected under the pallets. All the shells had a hole punched in the top of the shell which ranged in size from 0.5 cm to 1 cm. Otherwise the shells appeared undamaged.

What might have made the collection?
Rod Hobson
Posts: 509
Joined: Thu Jan 19, 2006 8:03 am

Snail shell collection

Post by Rod Hobson »

Steve,

The situation that you observed with the snail shells is a very typical habit of the Black Rat (Rattus rattus). This introduced rodent is known to eat the Garden Snail (Cantareus aspersus) and leave neat caches of their empty shells.

This rat is thought to have originated in south-east Asia, India and southern China but is now a cosmopolitan species. It is very common in Toowoomba and the surrounding bushland. The Black Rat is a very good climber and often found in house ceilings. It is a very attractive rodent; much more handsome than our local native rats. Rattus rattus can easily be identified from local native rats by the length of its tail, which is much longer than the combined lengths of its head and body. In our remaining local Rattus spp. the tail is shorter than, equal to, or only very slightly longer than the head-body length. The Black Rat also has very large ears that, when adpressed (pushed forward) easily cover the eyes. The ears of the local native rats do not cover their eyes when adpressed.

Black Rats are omnivores. I have found separate caches of macadamia nuts and dog biscuits put up by this rodent in times past. They'll often cart these sorts of objects up into ceilings, as well. The constant noise from a Black Rat rolling a macadamia around the ceiling can get very aggravating after a while. I should add that the Black Rat and our local native Bush Rat (Rattus fuscipes) are both well capable of gnawing through the very hard shell of the macadamia to get at the fleshy kernel. The Black Rat also has a disturbing habit of chewing through the plastic coating of electrical cables in ceilings that has resulted in house fires; not a great rodent to have around as your house guest at all.

This has been a great year for Black Rats around Toowoomba following the good rains.

Steve, I reckon that Rattus rattus is your snail-caching culprit. And that great Aussie battler, the Common Bluetongue (Tiliqua scincoides) is a far better biological controller of Garden Snails than is the Black Rat.

Regards,
Rod Hobson
Last edited by Rod Hobson on Thu Jun 03, 2010 10:13 am, edited 10 times in total.
sburke
Posts: 158
Joined: Wed Mar 11, 2009 10:30 am
Location: Townsville Region

Post by sburke »

Thanks Rod.
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