Tuesday, March 20, 2007

Naked Mole Rats -- An Encomium

One of the things I enjoy about knowledge is that it fosters attentiveness. The words of foreign tourists are white noise unless you know their language, the patterns of sediment deposits meaningless until you walk by with a geologist. I used to play frisbee with a group of ornithologists, and if a neighborhood hawk flew over the game would halt and there would follow a discussion of its plumage, its preferred diet, its economy of movement.

I am not the first to sing the praises of the naked mole rat. Dawn Coyote pointed out that a quarter of a documentary was devoted to an expert on the species. The National Zoo has a naked mole rat cam and handy article describing their salient characteristics. The BBC has some great pictures.

These sources tell us that the naked mole rat lives underground and that it is more closely related to the porcupine than to the young-tough-Norwegian rats that lurk about the New York subways like extras from Kids. They congregate in colonies and act more like what you might expect from an ant or a bee. There is a queen with a harem of a few males, and they handle the copulating. The other members of the colony do not reproduce; and the males are sterile. They are the "workers" who dig around and look for food, helped along by two big front teeth. According to the article:

The incisors can be moved independently, spread apart, or moved together like chopsticks. …When working together to dig tunnels in the wild, naked mole rats line up nose to tail and operate like a conveyer belt. A digger mole rat at the front uses its teeth to break through the new soil. Behind the digger, sweepers use their feet and fine hairs between their toes to whisk the dirt backwards. At the back of the line a "volcanoer" kicks the dirt up onto the surface of the ground, creating a distinctive, volcano-shaped mole hill about the height of a ballpoint pen.

So one interesting thing about mole rats is their social nature, the way they work together. Apparently they roll in feces, allowing members of a colony to recognize each other by smell. The actions of the whole colony are greater than the sum of its parts, much like a beehive or an anthill.

There are good genetic reasons for this level of social cohesion. The naked mole rats are highly inbred. If I am a worker naked mole rat, it is thus likely that my brothers and sisters share the same genes as I do. My genes are thus "our" genes, and to spread them to future generations, the mole rat division of labor can make sense. Leave the actual childbearing to the experts (in a year, the queen can have four or five litters of 12 to 27 pups), and as a worker I can specialize in finding food and defending the nest. Workers have been known to attack snakes, sacrificing themselves for the good of the colony. This system will continue because the genes that create these behaviors continue to propagate.

As I understand it, any female can be queen (there is a chemical trigger for queen-like behavior). When the queen dies, the biggest females fight for the position, and to the winner belong the spoils.

To be clear, I don't find mole rats cute or human or endowed with admirable behaviors. I just find them interesting, and take a certain delight in my interest.

I'm glad that there is pleasure in knowledge, and I think that on the whole such pleasure is a social good. I say this even though I am aware that there is also pleasure in false knowledge – at the Great Wall of China I met a guy who was enjoying himself immensely because he thought it had been built by spacemen. "Just look," he said, "tangible evidence of aliens."

I'm glad there's pleasure in knowledge because it is so god-awful hard to change people's minds. When I teach about China I'm struck by the resilience of the stereotypes that students bring to class with them. Sometimes I feel that anything I say can be assimilated and categorized by any world view. And yet there is this pleasure of knowing, which brings with it a certain hope that the man at the Great Wall will sooner or later figure out that Chinese supply lines were more robust than those of Alpha Centauri, or that my students will accumulate enough tidbits that they will sooner or later come across something that does not fit into their respective Weltanschauung.

It's amazing when it happens – when the slow acquisition of facts forces painful revision of something you always thought to be true. As a teacher, I think I could do a better job of acquainting students with such pleasures.

At any rate, here is my encomium for the naked mole rat: it makes me happy.

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