When life gives you lemmings…..

If I had a games console I wouldn’t get anything done. (Are they called ‘games consoles’ today?) Just like when I watch a film, I am completely captivated by the make-believe world: I am in that world. There is nothing around me. No one around me. Fortunately today, family, work, and late night blogging, prevent my loss of time. I am tempted by some of the incredibly realistic looking games on these futuristic looking consoles, but if I did, I would do nothing else. Nothing. Except finish the game.

When I was younger, we had a few PC games. Ghosts and Goblins on the Commodore 64 was good fun, and anyone remember Rider on the old BBC Micro PC? These were fun games. Addictive to finish the level. But nothing like the complexity and storytelling of games around today. In these games you really are the characters.

There was one game that got me. Totally got me. Completely hooked. Level after level. Lemming after lemming. I had to save them all. Or as many as I could. Sacrifice a couple, that’s fine: it would benefit the group. The classic early 90s game, Lemmings, was the game that told me I should never own a games console when I grow up. The game starts with around 100 lemmings falling from a trap door into a screen, and they all start to follow the leader. The leader walks, bumps into rocks and gets turned around: the aim of the game is to guide as many lemmings as you can to the ‘exit’. You can build bridges, dig under rocks or ‘freeze’ one, so it acts like a block to stop others from walking off the edge of a cliff, or into water, or lava.

A screen shot from the Amega version of Lemmins. (image Public Domain)

A screen shot from the Amega version of Lemmings. (image Public Domain)

As addictive as it was, this video game is based on lies. I know this now. We were lied to. All of us. All the tens of thousands, possibly even hundreds of thousands of children sat there trying frantically to stop these little green haired creatures follow each other to their deaths. We were made to believe that lemmings blindly followed a leader anywhere. Even over a cliff. We were made to believe that these gorgeous little critters were suicidal.

Lemmus lemmus

Fluffy, adorable, Norwegian Lemming (Lemmus lemmus) is just one species of lemming. (Image by Oma Kuva. Public Domain)

Lemmings are anything but suicidal. If an animal is suicidal, then it is intentionally wanting to die. In fact, suicidal animals in nature are very rare. Male spiders and mantids knowingly offering themselves to a female to be eaten are famous examples of suicide in animals (it makes sense that the male will be providing the nutrients for the eggs which he will have fertilised). If a male can leave his sperm and get out alive, it prefers this option (I completely understand why). But in lemmings? Do they really all follow each other knowingly to their deaths?

Lemmings are rodents, closely related to voles. First appearing in the fossil record around 4 million years ago, they live in the cold, icy Arctic tundra. And when food is abundant they breed fast. Their population doesn’t just boom, it explodes. With so many lemmings, all the available food is eaten super fast, so naturally the lemmings spread out looking for new places to live. Many die on this new pilgrimage across the desolate tundra. But some do find new food and set up new colonies. Those few survivors set up home for the next season, and so it goes on. So this ‘mass suicide’ is actually the lemmings trying to survive. Many die on this search for food, and perhaps early observations of their mass migration across the barren landscape, spawned the myth of suicidal lemmings.

They are a very successful group of rodents, with around 30 different species. Eating a variety of plants including moss, grasses, herbs, and lichen, these cold living creatures have a thick fur to help keep them warm in their cold homes. Because of their limited range due to their preferred temperature, they are excellent climatic indicators in the fossil record. They are found in deposits all over Europe, providing another insight into the erratic changes of climate in the past.

The temperatue

The temperature of the last 500,000 years (in blue) reconstructed from data from the Vostok Core, Antarctica. Note the see-saw pattern in the blue graph. Temperature rises rapidly, then there are periods of cooling which appear to be slower. (Image Public Domain)

We know the past has been a see-saw of warm and cold periods (we wrote about how we can measure the past climates through ocean sediments). Those warm interglacials allowing hippos to bask in English rivers, and those chilly, glacials which lacked snow but had huge ice sheets covering much of the northern hemisphere. Even these extremes were punctuated by cold and warm periods within them. And our little lemming fossils help us identify these cold periods.

Two species of Lemmings were present in Britain during the Pleistocene: the Norwegian Lemming (Lemmus lemmus) and the Collard Lemming (Disrostonyx sp.). As the great glaciers covered much of Britain, any exposed land was cold, dry, and hard. Here lemmings were in abundance. As the ice melted, and retreated north, so did the lemmings territory. So they are missing from fossil assemblages during warmer phases. But, they do pop back into some assemblages, showing us that the warm periods (the interglacials) were punctuated by cold periods (stadials).

Lemmings are small little critters, and as such, so are their teeth. Teeth survive pretty well in the fossil record. Especially in cave sites. Owls use the sites, and regurgitate the fur, teeth and bones that they cannot digest. These pellets accumulate and show us what animals were living within a few miles around the cave. Collections in museums hold lots of fossils from sites across Britain, opening a window into the past. Unfortunately many of the smaller teeth are not identified, mainly because there are so many of them. More evidence of lemmings may lie hidden within small jars filled with teeth of voles, mice, and rats.

Lemmings did, somehow, make it over to Ireland around 33,000 years ago: other species of vole living in Britain are absent in Ireland. It may have been the chance result of a mass dispersal of lemmings as they searched for new food. Some were lucky enough to have survived rafting across the Irish Sea.

Lemmings were extremely abundant in Britain towards the end of the Pleistocene. But as the  glaciers went through their final retreat, the last of the lemmings in Britain followed. For Now…..

Written by Jan Freedman (@JanFreedman)

Further Reading:

Current, A., & Jacobi, R. (2001). ‘A formal mammalian biostratigraphy for the Late Pleistocene of Britain’. Quaternary Science Reviews. 20. pp.1707-1716. [Abstract only]

Kurten, B. (1968), ‘Pleistocene mammals of Europe’, The World Naturalist. [Book]

Stuart, A. J. (1982), ‘Pleistocene Vertebrates in the British Isles’, Longman. [Book]

Sutcliffe, A. J. (1985), ‘On the track of Ice Age Mammals’, British Museum (Natural History). [Book]

Vendela K. et al. (2014). ‘On the origin of the Norwegian lemming.’ Molecular Ecology. [Abstract only]

 

 

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3 Responses to When life gives you lemmings…..

  1. lanceleuven says:

    Fascinating. I had no idea they’d lived in Britain.

  2. Holly says:

    Full disclosure: I’m reasonably fond of video games as a genre despite almost never playing myself because I’m terrible at them. But, since it’s almost on topic, I’m going to risk playing devil’s advocate to make sure you’ve heard of the in production game ‘Saurian’…

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