Murine whimsy

[fivemack]

Logitech announced today that it had manufactured its billionth mouse.

I think (given that 2.2 million lab mice were used in England in 2007) that computer mice probably just about outnumber lab mice. There are about 25 million households in Britain, and I don't expect that each of them contains forty mice, so computer mice made by Logitech alone may well outnumber house-mice in Britain.

I'm always impressed how common humans are as an animal their size; the Great Wildebeeste Migration in Africa is of 1.5 million wildebeeste at 150 kilograms each, which is fewer individuals but probably a bit more mass than the daily Commuter Migration into and out of London.

Thanks to a very useful dataset pointed out by shimgray, I can say that there are more people than mice in the UK; however, field voles outnumber humans. For every other person in the UK there is a mole.

I can't find a good estimate for the number of rabbits in BritainThe survey suggests that there are about forty million rabbits in the UK. The cows outnumber the population of Greater London, but not by much, and I suspect cows are heavy enough that there's probably more weight of cow than of human in the UK.

Comments

[wechsler.livejournal.com]

That would require a cow to be 10 times the mass of a human?

[shimgray.livejournal.com]

Cows are "usually slaughtered before reaching 750kg", per Wikipedia, so if we assume a dairy cow is a bit heavier than that... yeah, it's about ten people on average, a person being 70-80kg.

Wood mouse population is probably ~40m, another 1.5m harvest mice, ~5.5m house mice - per this study (http://www.jncc.gov.uk/pdf/pub05_ukmammals_speciesstatusText_final.pdf)

[fivemack.livejournal.com]

Ah. It seems that different data sources have different ideas of what counts as a cow; dairy-industry ones don't count beef cattle, and some surprisingly large fraction of the national herd is calves which don't count as either 'dairy cow' or 'beef cattle'.

The authoritative 2007 Cattle Book (http://www.defra.gov.uk/animalh/diseases/vetsurveillance/pdf/cattlebook-2007.pdf)

says there are nine million cows, so each cow would have to weigh seven times as much as a person; I think cows are about 400kg, so that would put humans at about 55kg which seems a little low.

[emperor]

9m cows alive at any one time is a good estimate. Full-grown cows are significantly more than 400kg!

[the-magician.livejournal.com]

how many children are there in the UK? And given the rate of childhood obesity ... arghh, too many variables! :-)

Commuter Migration (from 2001 census) seems to back up the guesses ...
• Around 2.8 million Londoners travelled to work in London and over 2 million of these travelled to work outside their borough of residence.
• Around 722,000 people travelled from outside London into London to work with over 350,000 of these travelling into Central London.
• Over 1.5 million people commuted to Central London altogether, including those who also lived in Central London. Around 23 per cent of these workers were resident outside London.
• The total number of people in work in London from the 2001 Census was 3,805,655.
http://www.london.gov.uk/gla/publications/factsandfigures/dmag-briefing-2007-03.pdf

[ellarien]

55kg is about 9 stone, the low end of normal for a 5'8" female, so yes, probably below the average adult human weight.

[hairyears.livejournal.com]

Now google for comparative methane production.

preferred habitats

[adrian-turtle.livejournal.com]

I think (given that 2.2 million lab mice were used in England in 2007) that computer mice probably just about outnumber lab mice. There are about 25 million households in Britain, and I don't expect that each of them contains forty mice, so computer mice made by Logitech alone may well outnumber house-mice in Britain.

At first I thought you were talking about how many computer mice were likely to be in the average British household. Surely only 2 or 3, despite statistical skew from groups of engineering students living together, and geeks who never throw anything away? There are more bio-mice living around commercial food storage and preparation building than in private homes, just as computer mice tend to concentrate in office buildings.