I ((Contributed by Michael Kubisch)) came across an interesting article while browsing through my archives. ((Dirk van Vuren and Philip W. Hedrick. Genetic Conservation in Feral Populations of Livestock. Conservation Biology, Vol. 3, No. 3. (Sep., 1989), pp. 312-317.)) It is by now quite dated, but with global climate changes upon us, I think it may actually be more relevant now than it was 20 years ago. The article makes a case for the preservation of feral livestock which are descendents of animals that, once kept by humans, either manage to escape into the wild or are simply abandoned when no longer useful.
Not all species do this equally well. Sheep have a hard time managing on their own, while pigs, on the other hand, easily adapt to all sorts of environments. In the US there are an estimated 4 million feral pigs, many of which may be descendents of pigs brought over by the Spanish in the 16th century. Similarly successful have been feral horses in the US and camels in Australia, the latter being so abundant that there are efforts underway to use them for meat production.
The article makes the case for preserving feral livestock as a valuable genetic resource because the adaptation to life in the wild may have favored or preserved traits, for example resistance to specific parasites or a higher temperature tolerance, that domestic livestock may have lost.
Of course, there are drawbacks: in some countries feral animals are considered pests and there is no doubt that particularly pigs can and do inflict serious damage on the environment. And because of this there are often programs in place to eradicate or at least control feral populations, although such attempts have not always been all that successful. At any rate, in an age of changing climate conditions it might perhaps be more worthwhile to keep some feral livestock around than to try to get rid of it.Â