Last Chance?

I'm currently in Cape Town at a workshop called the Mathematics in Industry Study Group (MISG).  MISGs are held all over the world and the idea is to try to address real world problems by working on them with invited mathematicians, industry representatives, and graduate students for an intensive week.  Although only a week is set aside for the activity, the opportunity to focus on a single issue and the resulting brainstorming and enthusiasm is often surprisingly successful.  Everyone gives their time for free and research funds cover the other costs.  The problems must be proposed by industry, otherwise they often degenerate into problems mathematicians think are real world problems, and that usually means ones they can elegantly solve.  This year we have problems from the sugar industry, the mining industry, the glass industry, traffic planning in Johannesburg, and two ecological problems.  One of these is concerned with the plight of the rhino, and I was asked to moderate that one - as in herd cats - in order to keep things focused.  I think I was asked because the organizer believes I know about mathematical models and about rhino population dynamics.  I'm not sure why he thought that, but here I am.

Mathematical modeling is about trying to use mathematics and computers to mimic the behavior of real world systems.  The objective is usually better understanding of the way the particular system works, and often to make predictions of that behavior into the future.  The problems involved can be hugely complex requiring teams of scientists, reams of equations, and high performance computers – such as trying to estimate the effects of global warming – or they can be very small, simple models involving a few equations and estimates – such as modeling the growth of a large mammal population under ideal conditions.  Often the idea is to play “what if” games to obtain input for brainstorming sessions around an intractable issue.

A chunk in Vietnam

So back to rhinos.  Over the last few years the news about rhinos has not improved. The UN Convention on International Trade in Endangered Species (CITES) banned international trade in rhino horn in 1977, and since then three subspecies have become extinct in the wild and six species are critically endangered.  The biggest success story was with the Southern White Rhino (the northern subspecies is regarded as extinct).  Numbers grew from a virtual handful left in South Africa in the mid fifties to a population of twenty thousand spread all over southern Africa.  But the price per ounce for rhino horn on the black market in Asian consumer countries is now higher than that of gold.  With those types of numbers, poaching has rocketed and over 1000 rhinos were poached for their horns in South Africa last year.

The South African Government is giving serious consideration to making the sale of carefully controlled rhino horn legal.  Extensive population modelling work has already been done by a variety of groups here and overseas, and one thing seems to be clear.  If we do nothing more than at present, the rhinos are probably doomed.  A few will survive but the idea of sustainable wild rhino populations is probably a pipe dream.  But there is another scenario - farming rhinos.
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Sad looking, but safe

No one is particularly enthusiastic about this option in principle.  Rhinos are wild animals and they look best and do best left to their own devices in the African veld.  But rhino horn does regrow.  It is, after all, just compacted hair and hair keeps growing.  So farming is possible as a sustainable activity involving harvesting the newly-grown rhino horn every few years.  Still,although the white rhino is fairly docile, it is not an easy process to immobilize a rhino to cut off a chunk of its horn!  The event is liable to upset the animal.  Also rhino ranches – with fairly tame animals concentrated in a relatively small area – will be a huge attractor for poachers.  So high security costs must be built into the farming scenario.

There's another issue.  If we increase the supply of rhino horn, won't the market just increase?  Well, maybe.  But could we drive the price down by dumping large amounts of currently stockpiled rhino horn on the market?  Well, maybe.  Would poaching pressure ease off if the price of horn drops.  Yes, but how much?  There are lots of poor people out there willing to risks their lives for this sort of money.  (A previous model suggested that a poacher values his life at just $3,000!)

So why go to the trouble?  Why not just eradicate the poaching and keep the blanket ban on the sale of rhino horn?  The problem is that the market seems to be growing – especially in Vietnam – and because the amounts used in traditional medicines are quite small, the price of a whole horn can be sky high.  The game is now so lucrative that ALL the resources of the nature conservation authorities probably couldn’t control it. The South African government, private donors, land owners and tourist bodies have poured money into foiling the poachers.  As an example of what private game reserves are doing, the place where I have a share in a bungalow has cameras and sensors strategically located, a paramilitary camp of armed anti-poaching personnel, tracker dogs, a helicopter on call...  You get the picture.  No one would take that on, right?  Wrong.  On Christmas day we had an incursion, but because we had a tip off, we actually caught one of the poachers but the others escaped.  No rhinos were molested.

It's been estimated that the cost needed just to contain the current threat is over $100 million per annum. That money just isn't there.  And the hot charity of today will be displaced by something more newsworthy in the future.  Where is that money going to come from on a sustainable basis?

So how do the numbers stack up?  Well, there are about 500 natural deaths in the bush per annum and most of the horn from these animals is recovered.  That’s about 5,000lbs alone. Then, an adult rhino grows about half a pound of horn a year.  If every one of the 20,000 white rhino in South Africa had the new growth harvested each year (a completely ridiculous scenario, of course), that would be another 10,000lbs. There is also an ill-determined amount of rhino horn (legally obtained) in stock right now and this could be used to bridge the period until the ranching gets up to speed  and also to drive down the price.  Let’s say a sustainable total of around 7,500lbs building up to about 10,000lbs could be produced from farming and natural mortality per year.  Would that satisfy the demand?  Maybe.  It depends how the supply and demand curve works.  One would want to get the price down so that rhinos would be less attractive to poachers, but not drop it enough to significantly increase demand.

Good looking and safe?

An interesting marketing strategy could be borrowed from the diamond industry.  Consumers like to be sure that the items they are buying are genuine and reliable.  A rhino horn “pedigree” (similar to the Kimberley Process one for diamonds) could go out with the merchandise guaranteeing that it is legally and humanely obtained as well as absolutely genuine rhino horn.

So we're trying to see how all these scenarios would play out, using computers rather than risking rhinos.  There's lots of uncertainty and lots to try.  Wish us luck.  It may turn out to be important for rhinos.

Michael – Thursday.