NATURE HAS SOLUTIONS
By Peter Muller
Chair, C.A.S.H. - Committee to Abolish Sport Hunting
Board Member - Wildlife Watch, Inc.
Isn't hunting part of nature? Don't animals living in a natural
environment hunt? If we lead lives consistent with our own natures
and in harmony with our environment - isn't it natural to hunt to
obtain food? So what's wrong with hunting?
In nature, predation is a healthy and normal relationship that some
species of living organisms have with other species. There is nothing
wrong with it. In fact, it would be a bizarre and deteriorating ecosystem
that didn't provide for some sort of predatory-prey relationship
among some of its species. It is an essential part of nature.
Species that are in a predator-prey relationship have evolved together
in the same ecosystem; both species benefit from that relationship.
If predation were somehow impeded the ecosystem as a whole, as well
as the predator and the prey species would be adversely affected.
Nobody benefits from a limitation on or a prevention of predation
in a healthy ecosystem.
Over time, evolving in the same ecosystem, predator and prey species
have developed structural and behavioral adaptations that allow them
to be healthy predators or prey animals.
Just a few examples: Prey species usually are very fecund, they
tend to have large litter and short gestation periods. Rodents -
rats, mice, guinea pigs are typical prey species and are, as is well
known, among the most rapidly reproducing species among mammals.
For example, lemmings can have litters of about six offspring every
three weeks. This is nature's way of assuring that the species will
survive even though many succumb to predation. Mammals that have
no natural predators reproduce much slower by having small litter
(often one birth per pregnancy) and long gestation periods. Elephants,
who have no natural predators, typically give birth to one calf after
a 22-month gestation period.
The structure of the eye among prey species tend to be well-suited
for peripheral vision; their eyes are on the side of the head and
can be rotated to be alert to a predator approaching from any direction.
Among predators the eyes are in the front of the head; the eyes can
focus stereoscopically to allow the predator to assess the right
distance to overtake its prey. If we look at birds for example, we
see these different eye structures between the raptors such as owls,
hawks, and eagles as contrasted with the passerines, examples of
which are sparrows, starlings, and orioles.
The ability to move and survive on their own shortly after birth
(precocial) is again markedly more developed among the prey species
than among species that have no predators. The various species have
evolved these adaptation so they can all live and thrive in their
ecosystem.
A natural predator will take some of the prey species but not so
many as to endanger eradicating its entire prey base. Among species
that have co-evolved it is estimated that no predator species ever
takes more than about 10 percent of its prey base. The kill rate
for a predator attempting to take a prey animal is also relatively
low: Sometimes it is less than 10 percent, typically it is around
20 percent.
Predation, in nature, benefits both the predator and the prey species.
The predator species, and incidentally scavenging species, benefit
by having their food needs met by predation. The prey species, however,
also benefits. Since predators are typically only able to capture
bottom 10 or 20% of the prey animals in terms of general fitness;
they get the slowest, least alert, of that species. Predation removes
infected and diseased individuals, thereby reducing risk of further
contagion and spread of parasites. Predation also removes congenitally
weak animals, preventing them from breeding, thereby improving the
gene pools of the prey species. The prey species is healthier and
genetically improved by having predators. The entire ecosystem benefits
from this kind of continuing interspecies interaction. This is natural
predation and it promotes biodiversity - it encourages the evolution
of variations of species and subspecies through adaptations of both
the predator and the prey species.
Hunting by humans operates perversely. The kill ratio at a couple
hundred feet with a semi-automatic weapon and scope is virtually
100 percent. The animal, no matter how well-adapted to escape natural
predation (healthy, alert, smart, quick, etc.) has virtually no way
to escape death once it is in the cross hairs of a scope mounted
on a rifle. Nature's adaptive structures and behaviors that have
evolved during millions of years simply count for naught when man
is the hunter.
Most deer, for example, would not perceive anything that is within
the outer rim of the effective range of a big game rifle (about 500
feet) as a predator or a source of danger. A wolf at that distance,
even though detected, would be totally ignored. Even the much smaller
range of bow-hunter (about 50-75 feet) is barely of concern to deer.
Deer may start to keep an eye on a hunter at that distance, but the
evasion instinct doesn't kick in until it's too late.
Hunters go after healthy big animals for trophies and meat. This
leaves the diseased and congenitally weak animals to breed --thereby
degrading the gene pool and spreading disease. The hunted species
becomes a degenerate and runty imitation of the real species that
evolved in the habitat before human hunting. Hunting by humans has
never been akin to natural predation. Using modern technology makes
matters worse, but even hunting by indigenous people, before the
blessings of Western civilization were bestowed on them, was just
as destructive only at a slower rate. The North American mammoth,
the Patagonian giant sloth, the pygmy hippopotamus, the elephant
bird of Madagascar are just some examples of animals that were hunted
into extinction by indigenous hunters.
To see exactly how hunting is destructive to an ecosystem, let's
look at a specific game animal. Probably the most widely hunted animal
in North America is one of the common species of deer (white-tailed,
mule deer, or black-tailed with an aggregate of about 50 subspecies)
Let's consider a naturally segmented area has sufficient browse
to feed a deer herd of 400 animals. Wildlife biologists would describe
this by saying that the biological carrying capacity of the area
for deer is 400. A territory has associated with it a carrying capacity
for each species that has naturally evolved there. Nature has mechanisms
in place to ensure that the carrying capacity that is appropriate
for that species is not exceeded.
What would happen if the deer population increased to substantially
over 400 in one year?
Let's say that with all normal control mechanisms in place (including
natural predators) the herd size reaches 500 healthy individuals.
At the start of the next rut, several mechanisms would kick in to
ensure a smaller amount of fawns the following year. If deer are
hungry (not starving, but not well fed either), the sex drive of
the bucks declines and the does stop ovulating or become receptive
less frequently than they would if plenty of browse is available.
Since the browse is now insufficient to feed all 500 animals, a portion
of the deer population would not reproduce during that season. With
the normal die-off during the winter and the smaller than normal
birth during the spring, the total population would be reduced to
less that 500.
Within a few seasons the populations would again stabilize around
the capacity of the territory. If the herd size dropped substantially
below the carrying capacity (say to 300), other natural mechanisms
would kick in (for example, does who have lots of browse during the
rut are more likely to have twins or triplets) to bring the population
back up to the normal carrying capacity of 400. Many other mechanisms,
some simple and some fairly involved and not yet completely understood,
are used by nature to maintain the population at the carrying capacity.
These mechanisms with which the species have evolved have, built
into them, assumptions that have been true for millions of years.
Human hunting totally destroys some of these assumptions
Normally, left to their own devices, the sex ratio of male to female
animals is about 50-50. Deer are born about evenly male and female.
Most "sport" or "trophy" hunters prefer to take
bucks rather than does. Almost state game agencies mandate that during
the regular hunting only bucks (antlered deer) and no does are shot.
Under certain extreme conditions, where a deer population has totally
mismanaged for years "doe permits" are issued in addition
to the regular deer tags in a desperate attempt to mitigate the mess
that the agencies have created over the years. This policy of shooting
out bucks distorts the gender ratio of the population.
Let see what happens when that ratio changes from 50-50 ratio to
80-20 -leaving four times as many does as bucks This is not at all
uncommon. In Texas and the Southwest, in general, years of mismanagement
have pushed the doe to buck ratio as high as 10:1 in some areas.
Let's look at two herds - one unhunted with the gender ratio intact
at 50/50 and one hunted and one hunted with the gender ration skewed
to 80/20. Otherwise everything is the same both herds live in an
area where there is sufficient browse for 400 animals. Nature's mechanisms
that adjust the population to the browse will now miscalculate and
cause an overpopulation for the hunted herd but leave the unhunted
herd stable at 400 animals.
Based on 50-50 ratio, a herd of 400 will consist of 200 bucks and
200 does. Normal browse conditions signal to each doe to give birth
to a single fawn. Assuming a winter die-off of 100 deer. The surviving
herd would consist of 150-buck and 150 does. Each of the 150 does
would give birth to 150 fawns. The herd sized, including the new
150 fawns is now 450. Fawns have about a 2/3 chance of surviving
until the next fall because they are subject to more predation than
adult deer; for example, coyotes will predate on fawns but rarely
on fully grown deer. Other mortality rates are also higher for fawns
that adult deer. At the next rut the herd is back to 400.
Based on an 80/20 gender ratio, a 100 animal winter die-off, and
normal browse conditions there will 240 does and 60 bucks in the
surviving herd. The 240 does will give birth to 240 fawns of which
160 will survive. At the next rut the herd size is now 460 instead
of 400. That's a 15% increase over the normal herd size. A few successive
seasons like that and the herd approaches conditions where massive,
catastrophic starvation and die-offs are inevitable.
Hunting is not the cure but the cause of overpopulation and starvation.
Luke Dommer, the founder of the Committee to Abolish Sport Hunting,
has proposed to several times to various state wildlife agencies
that if they are serious about using hunting as a population control
tool in areas where the sex ratio is already badly distorted, they
should institute a doe-only season. (Taking no bucks but only does
until the ratio is again stabilized at 50:50). All agencies have
rejected that proposal - thereby giving up any pretense of ecologically
motivated sound wildlife management. They quite consciously and openly
state that they are in business to provide the maximum number of
live targets to hunters each year.
The state agencies encourage the destruction of the naturally evolved
ecosystem by encouraging human hunting that balloons the population
of the game species at the expense of the non-game species. Management
techniques, in addition to sex-ratio distortion, include removal
of natural predators (e.g. wolves, coyotes, panthers, bears) altering
the natural habitat to provide additional browse for game species
and destroying the habitat of non-game species (e.g. clear-cutting
and/or burning areas and sowing them with oats for deer at the expense
of rabbits, voles, various reptiles and amphibians - and many other
non-games species.)
Things sometimes go totally haywire if a species is introduced into
an ecosystem where it didn't evolve. Biologists call such an organism
an "exotic" animal or plant. If the exotic animal is a
prey species, it may have no defenses against a local predator and
be totally wiped out in a very short time. On the other hand, it
may not have any local predators and consequently proliferate beyond
the carrying capacity of the territory, causing catastrophic die-off
through starvation.
If an exotic predator is introduced, the exotic species itself may
die out if there is no suitable local prey. Or, it may cause the
extinction of local prey species who have no defenses against the
exotic predator. Or, it may cause the extinction of local predators
if it is more successful and out-competes the local predator species
in taking the prey.
Numerous examples of the consequence of introduction of exotic organisms
within environments where they have not evolved can be cited: The
introduction of snakes into Guam during World War II to control the
rat population nearly wiped out several indigenous bird species;
introducing trout for sport fishing into Lake Titicaca in Peru in
the 1930s wiped out about 25 species of local fish. Those fish were
not found anywhere else in the world. There are hundreds of examples
where the introduction of an exotic species had a deleterious effect
on an ecosystem.
The wildlife management agencies defy sound procedure by such practices
as introducing exotic game species into areas and then distorting
the habitat to favor their survival at the expense of native species
that have evolved in the area. e.g. stocking an area with pheasants
-an Asian bird-and cutting tall timber trees needed by native raptors
for perches.
The activity of human hunting is not and never has been a sustainable,
mutually beneficial, predator, prey relationship. Human hunting techniques,
even the most primitive ones, are far too efficient to meet the conditions
required of a natural predator-prey relationship. In modern times,
with new technology, the efficiency becomes totally lopsided so as
to cause instant habitat degeneration Add to this the conscious mismanagement
of habitat to further degrade and obviate all natural corrective
measures.
Using techniques such as sex-ratio distortion, habitat manipulation,
the removal of natural predators and the introduction of exotic game
species destroys biodiversity. The goal is to maximize the number
of targets for human hunting, thereby destroying the naturally evolved
ecosystems and putting them at the brink of total collapse.
The number of animals of game species (native and exotic) is maximized
at the expense of all others. The naturally evolved mechanisms that
insure biodiversity are short-circuited.
The only way that these ecosystems can recover is to prohibit human
hunting and all other forms of nonsustainable consumptive uses of
these animals. We should allow for the unfettered reintroduction
and re-immigration of predators (which is occurring naturally). Stop "managing" the
environment of those areas. When it comes to managing the environment,
our knowledge is inadequate to do an even passable job. Even given
an ethically sound motivation, which the state agencies now lack,
we simply don't know enough to do a better job than nature.
Rather than playing God, we 're acting more like the three stooges,
when it comes to managing ecosystems. For the sake of life on earth,
we must not allow the hunting and gun-manufacturing lobbies to continue
to dictate wildlife management policies.
