23: Lemmings

Whilst many of the creatures that live in the Arctic are big, like polar bears and reindeer, smaller critters do exist there too. One of these is the lemming, a small hamster-like rodent that is found across tundra environments in the north. This week we’ll be learning about them, how they have a big effect on their ecosystem, and some of the odd misconceptions that exist about them. Hope you enjoy!

Lemmings are from the same family as muskrats and voles (Picture: FramePool)

Basic info

Lemmings belong to the same biological family as muskrats and voles, and are small at around 13-18 cm. They are herbivores, eating mainly grasses and mosses, though will munch on bulbs, lichens and berries if they come across them. Unlike many Arctic animals, lemmings don’t hibernate during winter, but stay active throughout this season. They build burrows and tunnels under the snow, using grasses, feathers and muskox wool to make nests. They even having little separate toilet rooms. Very tidy!

These tunnels help to keep them warm too, as snow insulates so the temperature underneath it can be much warmer than the temperatures in the open air. The tunnels also help to protect them a bit from predation, though not completely. If you look back to plog 9: The Arctic Fox, you can see a video of an Arctic Fox face planting the snow trying to reach the lemmings below. Lemmings are also hunted by owls, hawks and stoats.

During summer lemmings will also live in cracks and crevices in rocks.

A lemming emerging from its underground burrow (Picture: kgleditsch/ Flickr/CC BY-SA 2.0)

Population growth

As a species, lemmings reproduce incredibly fast. Normally a population will slowly grow until it reaches the ‘carrying capacity’ of the environment. This is the population which the environment can sustain with the amount of food, space and other resources present. After this, the limits on resources will stop the population getting any bigger, with excess numbers of animals dying off. Lemmings ignore this however, and seem to do their own thing. They make so many babies so quickly that their population hugely overshoots the carrying capacity of the environment. Because of this, lots cannot survive and starve as all the food is eaten away, and there is a massive population crash, sometimes nearly to extinction. Then a few years later once it has started to recover the population explodes again, creating a cycle of exploding and crashing in population which seems nonsensical.

This erratic population cycling affects the other animals in their ecosystems too. The predators which feed on them will suddenly have an abundance of food so can gorge themselves, and those that might normally starve will have enough food, allowing their population to grow too. Then of course then the lemming population crashes, taking away an important food source from the predators causing their number to go down too, and so whilst not as extreme the predators end up having population ups and downs because of the lemming too.

There are also some arguments that this might be the other way around- high predator numbers mean low lemming survival and population crashes, whilst low predator numbers mean high lemming survival and population growth. It’s hard to tell which way round it is, as ecosystems are a complex tightly interwoven web. It may even be a bit of both.

File:Snowy owl at Jones Beach (04863).jpg
Lemmings are hunted by snowy owls (Picture: Rhododendrites/Wikimedia Commons/ CC BY-SA 4.0)

Unusual traits

Lemming shave a few unusual traits compared to many other tiny prey species. For example, some lemming species are quite brightly coloured. You would think that to avoid being eaten in a snowy environment, it would make sense to be white to blend in with the surroundings. That is what animals like ptarmigans do. However, lemmings throw caution into the wind and are loud and proud with their bright colours.

Unlike many other rodents, which normally run away when faced with danger, lemmings are quite feisty and will be aggressive towards predators and even humans sometimes. It is thought both these things come together to create a defence system. The bright coloured fur that some (not all) lemmings have, like poisonous frogs and wasps are brightly coloured, acts as a warning signal to tell other creatures not to mess with them and the aggressive behaviour supports this warning.

This aggressive behaviour comes only from the Norwegian Lemming, and a video is attached at the bottom where the wonderful Chris Packham explores this more. You can even see the lemming chase a cat!

Lemmings can be feisty critters (Picture: Andreaze/Wikimedia Commons/ CC BY-SA 3.0)

Odd misconceptions

Right, there’s a really famous misconception but we’ll come to that in a minute. Let’s start with a more obscure one first.

Both Inupiat/Yupik folklore from Alaska, as well as a theory created by geographer Zeigler of Strasbourg suggested that lemmings are created by spontaneously falling out of the sky during storms, and then suddenly die when the grass start to grow in spring. Unsurprisingly this was later proven untrue, though it was suggested that the little critters could be caught in strong winds and carried by a storm to a new area.

Another odd misconception is that lemmings explode. Apart from explosions in population number, no, the animals do not spontaneously combust.

The most famous misconception is the whole “lemmings commit mass suicide by jumping off a cliff” thing. This is not true. Sometimes when there are too many lemmings in an area they may migrate in large groups to find a new place to get enough food. Sometimes this might include swimming across a body of water, and if it is poorly chosen the lemmings may drown, but they don’t jump off cliffs for fun. Now Disney fans, I’m sorry to inform you but Walt and his pals not only helped to make this myth famous but did so by being *!$%holes. A Disney documentary called White Wilderness purported to show the lemmings committing these mass suicides, but it was actually staged. The crew forced the lemmings off cliffs by chasing them or throwing them off and then filmed it with careful camera angles. Not very nice…

It’s such a popular myth however that it is often used as a metaphor for people blindly following each other into bad situations.

Lemming logic, the idea of committing mass suicide by jumping off a cliff, is often used as a metaphor for blindly following others into bad situations. For the record, I have no idea what Birmingham city council did here but apparently someone thought it wasn’t good.. (Picture: Stantos/The Birmingham News)

Though small, lemmings have a big impact on their environment- their food, their predators and the popular media that surrounds them. They are feisty, hardy and really quite cute. Whilst it’s cool to focus on the dramatic big creatures of the Arctic, sometimes it’s nice to celebrate the little guys too.

For more info:

An Encyclopaedia Britannica article on lemmings: https://www.britannica.com/animal/lemming

Chris Packham and Nick Crumpton explore the feisty behaviour of the Norwegian Lemming

Music: kongano.com

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