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CASH Courier > 1998 Fall Issue

Selected Articles from our newsletter

The C.A.S.H. Courier
From the Fall 1998 Issue

HUNTING BY HUMANS PERVERSE, TOO EFFICIENT

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.


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