Messing around in boats
June 23, 2013 11:56 AM   Subscribe

"For nearly two centuries, biologists have been struck by a mystery of geography and biodiversity peculiar to Europe. As Edward Forbes pointed out as far back as 1846, there are a number of life forms (including the Kerry slug, a particular species of strawberry tree and the Pyrenean glass snail) that are found in two specific distant places—Ireland and the Iberian Peninsula—but few areas in between." -- How did a specific snail species from the Pyrenees end up in Ireland but nowhere else?
posted by MartinWisse (16 comments total) 16 users marked this as a favorite
Does anyone know of similar evolutionary mysteries where the dominant theory involves humans?
posted by jrsnr at 12:52 PM on June 23, 2013

Looks like more strong support for the British-Iberian Celts theory.
posted by vacapinta at 1:17 PM on June 23, 2013 [2 favorites]

Really, there's just no end to the mischief those crazy Basques got up during the middle ages.
posted by hobo gitano de queretaro at 2:43 PM on June 23, 2013 [1 favorite]

Does anyone know of similar evolutionary mysteries where the dominant theory involves humans?

There are similar stories of animals introduced into unfamiliar ecosystems by humans, but there's nothing mysterious about it, because they've been well-documented. There's the introduction of the rabbit into Australia and kudzu in to the Southern U.S.
posted by jonp72 at 2:46 PM on June 23, 2013 [1 favorite]

Trade routes would've been my first guess. It's not that different from the way that foods and cultural memes spread in the New World along the "island nation" that was the East Coast.

I suppose the interesting part of this mystery is what the trade consisted of, goods-wise, that went between pinpoint locations but not, presumably, other ports between.
posted by Miko at 3:08 PM on June 23, 2013

It's not exactly an evolutionary mystery, but the introduction of Southern American sweet potato to Polynesia in 700-1000 A.D. requires pre-European contact between these two areas, we know that Polynesians got to South America at least once from chicken bones in Southern Chile dating to ~600 AD, but the return trip is daunting to say the least. There is a slow accumulation of evidence for intentional repeated trade between these two areas which fascinates me.
This is the paper you want to check out if you're interested.
posted by fido~depravo at 3:24 PM on June 23, 2013 [4 favorites]

Well this is just further support for my winged snail theory.
posted by angerbot at 4:56 PM on June 23, 2013 [3 favorites]

The British-Iberian Celts theory - the ancient Britons had all their Basques in one exit?

I'll be here all week. Try the fish.

I think I stole this from somewhere, but I can't remember where.
posted by cromagnon at 5:17 PM on June 23, 2013 [5 favorites]

posted by homunculus at 5:24 PM on June 23, 2013 [1 favorite]

The Orkney Vole has a similar history, being most probably imported to the islands by the first settlers as a food animal - same timing, same area of origin. I'm a bit surprised that the snail findings are seen as such a surprise.
posted by Devonian at 6:56 PM on June 23, 2013

I suspect some form of giant peach.
posted by arcticseal at 6:59 PM on June 23, 2013 [1 favorite]

As a child who spent half his life up Irish Strawberry trees munching away at their delicious fruit, I was always told that they occurred in both places because Ireland had broken off from Portugal in a fit of pique at the quality of the local beverages, and was slowly escaping north as fast as a largish island can.

(I think I prefer that version of events..)
posted by Ahab at 8:23 PM on June 23, 2013 [1 favorite]

It is odd that that snail map shows few or no samples on the Iberian peninsula save for near the Pyrenees. Why is that?

Because my Portuguese wife assures me that those snails are found in Portugal as well.
In any case, the explanation seems pretty clear to me.

At some point in the distant past there was a mass migration of people from the Iberian peninsula to Ireland. My guess is they were following a fishing route and decided to form a permanent settlement. Snails are a favorite ancient foodstuff. They eat vegetation, they reproduce fast and they are healthy to eat. In fact, you can still stop at many cafes in Lisbon and order a beer and a plate of snails to go with it. (link to my flickr photo)

It makes sense that the settlement would have brought along some of its favorite foodstuffs. And, although there were trade routes up and down the Atlantic, only a settlement produced a large enough snail breeding population that they have survived to this day.
posted by vacapinta at 3:02 AM on June 24, 2013

I read an Irish Times piece recently that linked the Irish badger, once believed to be more-or-less the same as those on Great Britain, to those found in Spain and Italy. In Ireland we have a genetically distinct badger, whereas those in Great Britain are a mixture of populations linked to central Europe.

An extended study revealed similar patterns in pine martins and pygmy shrews:
The study considers DNA clues to “an Atlantic fringe element” already found in Irish mammals, such as the pygmy shrew and pine marten. While the hair, grease and meat of badgers could have earned them a place in the boats of prospecting Neolithic Spaniards, the team could find no evidence for this. Securely dated evidence for badgers in Ireland is absent until medieval times, yet, perhaps remarkably, the team entertains the chance that badgers could have colonised Ireland naturally – this from land to the southwest, exposed in the Ice Age.
So there is the boat theory for badgers, but also an opposing natural migration theory.

I never knew about the Kerry slug's dual citizenship. Fascinating post, thank you.
posted by distorte at 3:27 AM on June 24, 2013 [1 favorite]

There's the introduction of the rabbit into Australia and kudzu in to the Southern U.S.

Helix aspera, one of the more common snails in the Bay Area and ubiquitous in my youth was introduced as a foodstuff.
posted by Ogre Lawless at 3:54 PM on June 28, 2013

I was just talking to an archaeologist who told me they've been digging on the coast of Western Sahara and found vestiges of the Atlantic people! (don't know about snails but definitely burial sites and ceramics) This is very exciting stuff. Pre-historic sailing turns out to be amazing.
posted by Marauding Ennui at 5:53 AM on July 3, 2013

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