TROPHY HUNTING - Wildlife Conservation in China: Preserving the Habitat of China's Wild West - page 173

worry is that by burdening younger males with the now inevitable task of contesting a
dominance they would otherwise have no chance to achieve, they also get the higher
mortality that comes along with it.
There is, indeed, considerable evidence among North American bighorn sheep that
survival of subadult males (who either do not breed, or adopt breeding strategies that do
not require contesting with older males) is high, whereas once males reach a lifespan of
a decade or perhaps a dozen years, they tend to die out quickly. We do not find a gradual
diminution of older males, but rather an abrupt edge of lifespan, as though, having fought
their way to the top and succeeded for some years as a prime breeder, their available
resources are quickly depleted (and their teeth usually ground to uselessness). It turns
out, though, that the evidence that killing older males some years before their natural
death thereby hastens the death of younger males as well is quite weak. 16 If entire cohorts
of older males are removed by trophy hunting, the potential for this positive feedback
phenomenon, leading to yet higher mortality among males, seems real. But a trophy hunt
managed in this way would quickly destroy its very object, the old males that hunters
deem so valuable. Thus conservative offtake rates again appear to mollify this concern.
A fourth risk—and the one that population biologists are seriously concerned about—
deals with the evolutionary consequences of selectively removing the largest males (and
thus, in the language of geneticists, “selecting” for males that never achieve large size,
or do so relatively slowly). In theory, this risk is easily the most damning and most easily
comprehended of the four, in part because if artificial selection can occur for horns, it
likely can also occur for other, less obvious traits. If hunters, however unwittingly, pro-
duce strong artificial selection for certain kinds of animals, then natural selection—the
very essence of the wildness that hunters and wildlife managers both desire—is perforce
compromised. 17
To anyone familiar with evolutionary theory, it should be clear that by elevating the
mortality rate of individuals with a certain trait (large horns, in this case), and thereby
increasing the breeding opportunities for those with alternative traits (smaller, or at least
slower-growing, horns), the proportion of those with the alternative trait in the population
will gradually increase. 18 Indeed, this is the kernel of Darwinian evolution: survival of
the fittest, increasing representation in the population of those equipped with the genetic
basis for that fitness. Only in this case—at least according to the argument—trophy
hunting has skewed the existing definition of fitness from that which would be selected
naturally. By artificially increasing the mortality rate of those with traits that naturally
lead to reproductive success (big horns), it now becomes “fitter” to have smaller (or more
slowly-growing) horns because to have them increases one's chance of avoiding the trophy
hunter's bullet and thus living to reproduce another day. That such artificial selection can
alter the physical traits present in a population has been repeatedly shown in species as
disparate as fish 19 and elephants. 20
Fortunately for species of interest to trophy hunters, the situation is a bit more com-
plex than portrayed above. First, in order for artificial selection to play out in this way,
the phenotypic trait visible to hunters (horns, in this case) must be a heritable one. For
some time, it remained unclear whether, or to what degree, the size and conformation of