Sunday, April 1, 2007

Fertilizers and Butterfat

“Mice are actually the third most successful mammalian species living on earth today -right after humans and rats”, explains Ms. Ann Christine Carlson, a retired stewardess and mother of two. Her fascination with the little critter began while she was pregnant with her first child back in the mid 1970s. “I had just moved to Copenhagen” she recalls, “and was missing the Swedish countryside so intensely, not least because I was living in a 4th floor walk-up with no balcony”. Her solution was to create a small hothouse on her kitchen windowsill.

“I was living close to the national zoo, and struck up a deal with one of the elephant keepers, who gave me dung in exchange for sachets of honey-roasted peanuts. He had totally fallen in love with those things during a flight to The Hague a few years earlier, and elephant dung is just such a good fertilizer for heirloom tomatoes”. The weekly exchange between the stewardess and the elephant keeper gradually developed into a close friendship. “We still remain good friends”, Ms. Carlson says with a smile, “after all, he was the one who eventually sparked my interest in mice”.

The elephant keeper, it turned out, was actively experimenting with the fertilizing qualities of droppings from a wide variety of animals kept in the zoo. “One day”, Ms. Carlson recalls, “he brought me two small zip-lock bags with tiny little droppings in them, suggesting I give them a try”. She did, and the result was amazing, causing her to invest in two house mice herself. “That was how the love affair began”, she says.

Since then, however, her interest has taken a dramatic twist. “I’m more into studying their behavior and categorizing them according to a set of criteria, which I have developed other the last three decades”. “I still use their droppings for fertilizers though”, she says with a contagious laugh. “I really recommend it. So much energy is tied up in those little things. But you know, you should only go for the well-formed ones. It’s a sign of good health if you can pick it up without it leaving a skid-mark on your hand”, she tells while picking up an oat-sized mouse dropping on the floor of her Stockholm apartment.

As it is, Ms. Carlson is letting her house mice roam around the place as they please. “I think there are around half a dozen living here at the moment, but I’m not entirely sure. I try to not meddle too much in ‘the eco-system of the apartment’, so to speak”. ”Also, they are nocturnal, you know, so god knows what they do at night when my husband and I are asleep!”

Well, quite a deal it turns out. “They are surprisingly human like, with genetics close to ours, which is also why they are used so much for medical research”. “Anyway, I put up a surveillance camera in the kitchen for a two week period, and found that they often hump on the espresso maker. At our house, the espresso maker is always on, and it seems that they like the fact that it’s so warm and that it vibrates slightly. It appears they get a kick out of it”.

Taking into account the short breeding cycle for rodents, it seems to be a fortunate thing that a good percentage of Ms. Carlson’s mice are infertile. “It would be a mess otherwise”, she says while rolling her eyes. “Plus they get such horrible eye infections when put under stress. It’s funny, because they are extremely sociable, but all the same it seems they thrive better in relatively small groups”. The high percentage of infertility, it turns out, finds its explanation in a little human interference. “I don’t give them contraceptives”, Ms. Carlson laughs, “it’s all natural, really”. “I met this wonderful woman while researching on a special sub-specie of the domestic mouse in Northern Malawi, who used a special herb to restrict the biomass of mice to protect the crops on her land”.

The herb, it seems, works wonders. According to Ms. Carlson, the mice are not suffering from any side effects. If anything, it appears to lengthen their life span – otherwise considered to be the biggest drawback of the house mouse. “On average they life for about 1,5-2 years, but mine seem to live 3-4 years”. “Celeste grew to be 4 years and three months”, Ms. Carlson recounts showing a picture of a well-nourished white mouse that seems to have a central place in her heart. “She was such a character. Always happy to see me, and traveled with me everywhere. We shared a passion for Italian cheeses, and would have a nightly rendez-vous in the kitchen to share a little Parmesan or Pecorino….that’s so unusual you know, they usually go for Jarlsberg, Leerdammer or other mild cheeses with a semi-firm consistency”.

It is evident that Ms. Carlson knows what she is talking about. Her Swedish citizenship places her in the top ten category of nationwide consumers of cheese. According to a 2003 survey, the average Swede eats 17.9 kilograms of cheese per person per year, something which Ms. Carlson has always done her best to keep up with. “I always cared immensely for cheese”, she explains, “and so I decided to combine my passions, using cheese preference rather than the shape of the lower jaw as the criteria for dividing mice into orders and suborders”.

The fossil record of rodents begins long before the extinction of the dinosaurs 65 million years ago, and except for Antarctica, you can find mice just about everywhere in the world. “They are the only placental order other than bats to reach Australia without human introduction”, Ms. Carlson explains, unable to keep her fascination with her little friends a secret. “How on earth they got there is beyond me, but they are clearly very intelligent given their size – which is exactly what I say about my husband”, Ms. Carlson says laughing out loud. “In any event, I just felt that studying them and categorizing them according to traditional systems of rodent taxonomy was so reductive. There is so much more to them, you know, than jaw size, length of tail and hibernating patterns”.

Ms. Carlson’s system of categorization has taken her around the world, studying mice in more than a hundred and fifty places. “Working as a stewardess has served me surprisingly well in that regard, not least in terms of establishing connections with other researchers and scholars, whom I am now able to work with”. Her next trip goes to Saratoga County, New York, where she and an old friend, a retired professor from MIT, are going to carry out research on the connections between butterfat content, cheese preference and identity formation. “My preliminary studies show that there really is a pattern in terms of micro-social behavior and cheese. If Celeste taught me anything it was that you can pretty much judge a mouse by the cheese it eats. Some of us just need to be a little less bland”. As this reporter can testify, Mr. Carlson is as far from Jarslberg as can be.

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