Über die Autorin bzw. den Autor

Cindy Engel has a Ph.D. in biology from the University of East Anglia, with a concentration on the relationship between physiology and behavior in animals. She has done research on the behavior and health of wild rabbits and jaguars and for twelve years has been a lecturer in environmental sciences at the Open University. She has published numerous scientific papers, particularly in the prestigious journal Animal Behaviour, and for the past eighteen months has worked as a script writer and science advisor for a series of wildlife documentaries being produced by National Geographic. In addition to her research into the medicinal practices of animals, she has studied holistic medicine for humans and is a Shiatsu practitioner. She has two children, lives on a farm in Suffolk, and is not quite forty.

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Wild Health

How Animals Keep Themselves Will and What We Can Learn from ThemBy Cindy Engel

Mariner Books

Copyright © 2003 Cindy Engel
All right reserved.
ISBN: 0618340688
1
HEALTH IN THE WILD
The multitude of the sick shall not make us deny the existence of
health.
— Ralph Waldo Emerson, 1860

The herbalist Juliette de Baïracli Levy has spent much of her long
life observing the way animals keep themselves well in the wild. In
one of her many books she writes, "Everywhere in the woods one
observes the wild animals rearing their young in health and freedom
from sickness."1 But this view is considered naively romantic by
wildlife health experts. Although an animal may seem healthy on the
surface, it may harbor diseases and parasites that drain its
resources and can flare up should resistance falter momentarily.
Furthermore, the animals we see are the survivors, disease and death
having filtered out the less healthy. The wild animal, from this
perspective, fights a perennial battle with sickness and disease.
Which view is correct—the romantic vision of a healthy and
harmoniously balanced ecosystem, or the survivalist vision of a
ruthless, endless battle with death and disease? Paradoxically, the
two views are not as diametrically opposed as they might first
appear. When we see a beautiful swan glide across still water, the
movement appears effortless; the swan seems calm and untroubled, even
serene. An observer below the water, however, would see that the swan
is working hard: muscles are contracting and relaxing; legs and
webbed feet are pumping, pushing water aside with great effort. So it
is with wild health. While an animal may appear to glide effortlessly
through life"s troubled waters, a continuous struggle for survival
goes on, largely unseen. One perspective, then, is that behind a
façade of blissful, harmonious balance, each and every organism is
working to maintain its health and to survive. Another perspective is
that the struggle and selective survival actually create the
impression of harmony. I find no conflict in being able to see both
the struggle and the balance in the same vista, but evidently the
answer to the seemingly straightforward question "How healthy are
wild animals?" is influenced by the perspective of the observer.
Most of us gain our impressions of health in the wild
primarily from the news media—and news about wildlife, like news
about anything, is seldom good news. Currently, wildlife health makes
grim reading. Seal and dolphin populations in the Mediterranean and
Baltic seas, and in the coastal waters of the United States, have
been seriously affected by major disease outbreaks. It looks as if
the butylins used to protect the hulls of ships from barnacles and
such are the main culprits. These biocidal chemicals damage mammalian
immune systems, lowering resistance to disease and cancers.
Meanwhile, harbor porpoises in the English Channel and southern North
Sea are sickened by the high concentrations of polychlorinated
biphenols and mercury in their waters. And a global epidemic of
mysterious tumors affecting endangered sea turtles is linked to the
pollution of their watery breeding grounds.
On land, amphibians around the world are facing a health
crisis. Over the past two decades there has been a rapid decline in
their numbers, including extinction of some species, apparently
because of a global epidemic of a particular fungal infection.
Furthermore, the number of grossly abnormal amphibians born has
increased. Although the exact causes of this crisis are ambiguous,
environmental factors that disrupt both disease resistance and the
developmental systems of amphibians may play a role. All the main
contenders are caused by humans: global warming, agrochemicals, and
damage to the ozone layer.
Pollution distorts our impression of wild health, and the
occurrence of disease in wild-animal populations has become an
important indicator of ecological disruption. For a clearer picture
of how animals stay well, we need to assess the health of populations
far from the effects of industrial society. But even there our
presence can disrupt the survey. Early in the study of wild
chimpanzees at Gombe National Park in Tanzania, a polio outbreak
decimated the chimpanzees, killing four and leaving six permanently
disabled. It is thought that the virus spread from local humans, who
suffered a polio outbreak a month before, and was carried
inadvertently by vaccinated human scientists. The introduction of new
pathogens can be devastating for any population. The Spanish
conquistadors of the fifteenth and sixteenth centuries killed most of
the native Central Americans, not by superior warfare or cunning
intellect, but by bringing with them novel and consequently lethal
diseases (measles, for one). Today pathogens are traveling the world
with increasing ease as the international trade in food, plants, and
animals expands, and humans become increasingly mobile. As a result,
wildlife is exposed to many new diseases.
As the human population increases, the need for more and more
land for housing, agriculture, and tourism continues to squeeze
wildlife into ever-shrinking areas of natural habitat. Asian
elephants no longer have enough room to find the food and water they
need to stay well. Lions in the Serengeti National Park, along with
the last few viable populations of African wild dogs, have been
ravaged by canine distemper virus and rabies caught from domestic
dogs skirting the edge of the park. William Conway of the Wildlife
Conservation Society puts it succinctly: "Our growing herds and
flocks of domestic animals have become a plague to wildlife,
devastating habitat and spreading disease."
We hear far more about disease passed in the other direction—
from wild to domesticated animals. In Europe, wild badgers are blamed
by farmers for infecting domesticated cattle with tuberculosis, deer
are feared as carriers of foot-and-mouth disease because infected
herds can remain symptom free, and wild boar are hounded for
spreading classical swine fever (CSF) to commercial pigs because "CSF
has become milder in wild boar than pigs."3 In North America, free-
ranging bison are accused of spreading brucellosis to ranched cattle,
and wild deer of spreading tuberculosis to cattle. In what I consider
to be a totally illogical response, wild animals successfully keeping
disease at bay are often killed in order to protect sickly (but
profitable) domesticated livestock from infection. In the United
Kingdom, for example, a culling program is currently under way in
which twenty thousand badgers will be killed to prevent them from
possibly spreading tuberculosis to cattle.
This fear of wild animals as harbingers of disease is deeply
ingrained in the human psyche. The European hedgehog (small, spiny
heroine of a classic Beatrix Potter story) was recently described
as "among the most dangerous animals in Europe" by pathologist Ian
Keymer of London Zoo, who found that they carry at least sixteen
diseases known to affect people. And those "could be the tip of the
iceberg," he adds. "If we look closer we may find many more." Howard
Hughes would have understood, but if we follow this line of reasoning
to the extreme, we...