Wednesday, 8 September 2010

Ricochets and Repercussions

The title of this posting reflects the fact that you can't always tell what the long-term effects of your actions will be.

We watched a fascinating programme on Channel 5 last night, about a catastrophe in India. As so often with TV science documentaries, they stretched it out rather more than necessary.  I think they could have got away with a half hour or possibly 40 minute programme instead of the full hour they gave it.  I suspect this is a side effect of farming the actual programme making out to specialist companies;  obviously the production company would rather sell a longer programme for more.

The programme started by focusing on leopards moving into urban areas, with an increase in the number of children being attacked, which has generated a lot of panic amongst the local population, with some predictable killing of the unfortunate leopards by crowds armed with sticks.

Instead of sending out vigilantes to massacre the leopards, the Indians have done some basic research to find out why things have changed, and it turns out the leopards are primarily in the urban areas to predate a wildly booming population of feral dogs.  As their natural prey in the jungle has got scarcer, they've found an alternative food source, and now dogs form about 80% of their diet.

Next question, of course, is why are there so many dogs?  This needs to be answered for another reason, quite independently.  Many of the dogs carry rabies, and people are getting bitten.  You have to get the vaccine within 24 hours of being bitten by a rabid dog, and people just don't realise that.   The nice lady doctor explained that if you don't get the vaccine within the critical period, you die.  There is a 100% death rate for those not vaccinated in time.  I didn't know that, but then there's not a lot of rabies in this country, so I wouldn't expect to know it.

As you'll know, cows are sacred to Hindus, and in northern India they're allowed to wander as they choose and no-one is allowed to interfere with them.  When they die, their carcasses are collected up and taken to traditional dumping grounds, where they are just left.  This sounds gross until you realise that the vast populations of vultures could strip a carcass within an hour, so it obviously wasn't nearly as nasty as you'd imagine.

Only now there don't seem to be many vultures about, the carcasses lie around for ages, attracting dogs and flies.  The absence of vultures is a real problem in this respect and is the root cause of the problems with the dogs.  There's another thread to this tale, too.

The Jains are a religious group who, amongst other things, consider fire and earth to be sacred, which makes disposing of their dead somewhat problematic.  They can't bury the body or burn it because the flesh is unclean and would corrupt the earth or the fire.  So traditionally they've exposed their dead in purpose built towers and the vultures have come along and dealt with them in the same way as they used to deal with the dead cows.  No vultures means an accumulation of dead Jains, which is not a pleasant thought.

This all started to become obvious in the late 1990's and people started doing the research necessary to understand it.  The vultures were definitely dying, but no-one knew why.  As the numbers crashed, and by that I mean the number of vultures was halving each year, the Indian government declared them an endangered species, which made it a crime even to possess the carcass of a vulture.  This wasn't exactly helpful to the scientists trying to find out what was killing them.  If you can't have a carcass, how do you find out what killed the bird?

In the end they had to work in Pakistan, which has less rigorous enforcement.  They discovered that elderly cows were being given an anti-inflammatory drug called Diclofenac to ease the pain of rheumatism and arthritis.  When the vultures cleaned up the cow carcasses, they ingested the Diclofenac which caused kidney failure.  Doesn't cause kidney failure in humans or cows, just vultures.  I took Diclofenac daily for years after I slipped a disc and my kidneys are fine.

So a few years ago now, the Indian government forbad the sale of Diclofenac for cows, though some is still being used that way.  Presumably for some Hindus, it's preferable to ease a cow's suffering than to sort out the problems with vultures, Jains, carcass dumps, feral dogs, rabies and leopards.  In theory, with less of the drug being administered to cows, the vultures should start to recover.

There are also now captive breeding programmes springing up, where the vultures are fed drug-free goats, and that seems to be quite successful, though it'll be a long time before the populations recover to the millions that existed before.  Even the Jains are investigating starting their own captive breeding programme.

Quite where we are now, I don't know.  There's a long article going into much more detail than the TV programme at the Bombay Natural History Society website.  One of the things it details, which the programme omitted, is that the Indians have tested an alternative anti-inflammatory called Meloxicam and found that it's just as effective for the cows, but does no damage to the vultures.

Of course, it could do enormous damage to leopards, or crocodiles, or elephants, or rice.  Who knows?  Nobody's done the research.

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