Monday, July 2, 2012

[tt] NYT: Our Animal Natures

Our Animal Natures


AS an attending physician at U.C.L.A., I see a wide variety of
maladies. But I also consult occasionally at the Los Angeles Zoo,
where the veterinarians' rounds are strikingly similar to those I
conduct with my physician colleagues. Intrigued by the overlap, I
began making careful notes of the conditions I came across by day in
my human patients. At night, I combed veterinary databases and
journals for their correlates, asking myself a simple question: "Do
animals get [fill in the disease]?" I started with the big killers.
Do animals get breast cancer? Stress-induced heart attacks? Brain
tumors? How about shingles and gout? Fainting spells? Night after
night, condition after condition, the answer kept coming back "yes."
My research yielded a series of fascinating commonalities.

Melanoma has been diagnosed in the bodies of animals from penguins
to buffalo. Koalas in Australia are in the middle of a rampant
epidemic of chlamydia. Yes, that kind--sexually transmitted. I
wondered about obesity and diabetes--two of the most pressing
health concerns of our time. Do wild animals get medically obese? Do
they overeat or binge eat? I learned that yes, they do.

I also discovered that geese, gorillas and sea lions grieve and may
become depressed. Shelties, Weimaraners and other dog breeds are
prone to anxiety disorders.

Suddenly, I began to reconsider my approach to mental illness, a
field I had studied during the psychiatric residency I completed
before turning to cardiology. Perhaps a human patient compulsively
burning himself with cigarettes could improve if his therapist
consulted a bird specialist experienced in the treatment of parrots
with feather-picking disorder. Significantly for substance abusers
and addicts, species from birds to elephants are known to seek out
psychotropic berries and plants that change their sensory states--
that is, get them high. The more I learned, the more a tantalizing
question started creeping into my thoughts: Why don't we human
doctors routinely cooperate with animal experts?

We used to. A century or two ago, in some rural communities, animals
and humans were cared for by the same practitioner. And physicians
and veterinarians both claim the same 19th-century doctor, William
Osler, as a father of their fields. However, animal and human
medicine began a decisive split in the late 1800s. Increasing
urbanization meant that fewer people relied on animals to make a
living. Motorized vehicles began pushing work animals out of daily

Most physicians see animals and their illnesses as somehow
"different." Humans have their diseases. Animals have theirs. The
human medical establishment has an undeniable, though unspoken, bias
against veterinary medicine.

While it rankles when M.D.'s condescend, most vets simply take a
resigned approach to their more glamorous counterparts on the human
side. Several have even confided to me a veterinarians' inside joke:
What do you call a physician? A veterinarian who treats only one

My medical education included stern warnings against the tantalizing
pull to anthropomorphize. In those days, noticing pain or sadness on
the face of an animal was criticized as projection, fantasy, or
sloppy sentimentality. But scientific advancements of the past two
decades suggest that we should adopt an updated perspective. Seeing
too much of ourselves in other animals might not be the problem we
think it is. Underappreciating our own animal natures may be the
greater limitation.


PEOPLE who didn't smoke, drink or tan and who avoided microwaving
food in plastic and cooking on Teflon can develop cancer. It strikes
yoga practitioners, breast-feeders and organic gardeners; infants,
5-year-olds, 15-year-olds, 55-year-olds and 85-year-olds.

Even the briefest survey of cancer in other animals sheds light on a
critical but overlooked truth: Where cells divide, where DNA
replicates, and where growth occurs, there will be cancer. Cancer is
as natural a part of the animal kingdom as birth, reproduction and
death. And it's as old as the dinosaurs.

Osteosarcoma, the cancer that forced Ted Kennedy's son, Ted Junior,
to undergo an amputation in the early 1970s, attacks the bones of
wolves, grizzly bears, camels and polar bears. And the
neuroendocrine cancer that claimed the life of Apple's co-founder,
Steve Jobs, while rare in humans, is a fairly common tumor of the
domestic ferret and has been diagnosed in German shepherds, cocker
spaniels, Irish setters and other dog breeds.

Breast cancer strikes mammals from cougars, kangaroos and llamas to
sea lions, beluga whales and black-footed ferrets. Some breast
cancer in women (and the occasional man) is connected to a mutation
of a gene called BRCA1. All humans have a BRCA1 gene. But about one
in 800 of us are born with a mutated version, which increases the
risk for certain cancers. For Jewish women of Ashkenazi descent,
it's as high as one in 50. And BRCA1-related breast cancer occurs in
some animals, too: English springer spaniels, and possibly big cats
like jaguars.

But some groups of mammals, intriguingly, may be protected from it.

The latte you sipped this morning contained milk from an animal
sorority that very rarely gets breast cancer. Professional lactators
--the dairy cows and goats that make milk for a living--have
rates of mammary cancer that are so low as to be statistically
insignificant. That animals which lactate early and long seem to
have some protection against breast cancer is not only fascinating,
it parallels human epidemiologic data that tie breast-feeding to
reduced mammary cancer risk.

Another thing we can learn from animal cancer is the extent to which
it's caused by outside invaders: viruses. Veterinary oncologists see
this all the time. Lymphomas and leukemias among cattle and cats are
quite frequently viral. Many of the cancers sweeping sea creatures
from turtles to dolphins are rooted in papilloma and herpes viruses.
Between 15 and 20 percent of cancers worldwide are caused by
infections, many of which are viral.

And noticing where cancer isn't can be as instructive as noticing
where it is. Dogs rarely get colon cancer. Lung cancer is also
atypical, although short- and medium-nosed dogs living in homes with
smokers are susceptible. Canine breast cancer is rarer in countries
that promote spaying but quite common where most female dogs remain
reproductively intact. As the veterinary oncologists Melissa Paoloni
and Chand Khanna point out, two breeds of dogs seem to get cancer
less often than others: beagles and dachshunds. Like the
professional lactators who rarely get breast cancer, these
extra-healthy dog breeds may point to behaviors or physiology that
offer cancer protection.


ANIMALS don't have access to liquor stores, pharmacies or corner
drug dealers. But the intoxicants in those drugs are found in nature
--opium in poppies, alcohol in fermented fruit and berries,
stimulants in coca leaves and coffee. Given the opportunity, some
animals do indulge ... and get intoxicated.

Addiction researchers have shown that genetics, vulnerable brain
chemistry, and environmental triggers play roles in human substance
abuse. But ultimately, on the receiving end of the syringe, joint or
martini glass is a person making a choice, at least in the initial
stages of drug use. This makes addiction uniquely bewildering to
physicians, psychiatrists, sufferers and the people who care for
them. Why is it so hard for addicts to "just say no"? It turns out
that saying "no" is hard for animals too.

Cedar waxwing birds are known to ingest fermented berries, fly while
intoxicated and crash into glass walls. In Tasmania, wallabies have
broken into fields where medical opium was growing, eaten the sap
and got stoned.

Some animals show chronic drug-seeking behaviors. Bighorn sheep
grind their teeth to the gums scraping hallucinogenic lichen off
boulders in the Canadian Rockies; some Siberian reindeer seek out
magic mushrooms.

A friendly cocker spaniel in Texas once sent her owners' lives into
a tailspin when she turned her attention to toad licking. As
described in an NPR story, the spaniel, Lady, had been the perfect
pet, until one day she got a taste of the hallucinogenic toxin on
the skin of a cane toad. Soon she was obsessed with the back door,
always begging to get out. She'd beeline to the pond in the backyard
and sniff out the toads. Once she found them, she mouthed them so
vigorously she sucked the pigment right out of their skin. According
to her owners, after these amphibian benders Lady would be
"disoriented and withdrawn, soporific and glassy-eyed."

In lab settings, rats have been shown to seek out and
self-administer doses--sometimes to the point of death--of
various drugs, from nicotine and caffeine to cocaine and heroin.
Once addicted (researchers say "habituated") they may forgo food and
even water to get their drug of choice. Like us, they also use more
when they're stressed by pain, overcrowding or subordinate social
position. Some ignore their offspring.

Taking a species-spanning perspective of drug use reveals something
important: The urge to use has stayed in the gene pool for millions
of years and for a counterintuitive reason. Although addiction can
destroy, its existence may have promoted survival.

Here's what I mean: Foraging, stalking prey, hoarding food,
searching for and finding a desirable mate, and nest building are
all examples of activities that greatly enhance an animal's chances
of survival and reproduction, or what biologists call fitness.
Animals are rewarded with pleasurable, positive sensations for these
important life-sustaining undertakings. Pleasure rewards behaviors
that help us survive.

Conversely, unpleasant feelings like fear and isolation indicate to
animals that they are in survival-threatening situations. Anxiety
makes them careful. Fear keeps them out of harm's way.

And one thing creates, controls and shapes these sensations, whether
positive or negative: a cacophonous chemical conversation in the
brains and nervous systems of animals. Time-melting opioids,
reality-revving dopamine, boundary-softening oxytocin,
appetite-enhancing cannabinoids and a multitude of other
neurohormones reward behavior.

We humans get drug rewards for life-sustaining activities just as
animals do. We simply call those activities by different names:
Shopping. Accumulating wealth. Dating. House hunting. Interior
decorating. Cooking.

When these behaviors have been studied in humans, they are
associated with rises in the release of certain natural chemicals,
including dopamine and opiates.

The key point is that behaviors are the triggers. Do something that
evolution has favored, and you get a hit. Don't do it, and you don't
get your fix.

And this is precisely why drugs can so brutally derail lives.
Ingesting, inhaling or injecting intoxicants--in concentrations
far higher than our bodies were designed to reward us with--
overwhelms a system carefully calibrated over millions of years.
These substances hijack our internal mechanisms. They remove the
need for the animal to input a behavior, before receiving a chemical
dose. In other words, pharmaceuticals and street drugs offer a false
fast track to reward--a shortcut to the sensation that we're doing
something beneficial.

This is a critical nuance for understanding addiction. With access
to external drugs, the animal isn't required to "work" first--to
forage, flee, socialize or protect. Instead, he goes straight to
reward. The chemicals provide a false signal to the animal's brain
that his fitness has improved, although it has not actually changed
at all.

Why go through a half-hour of awkward small talk at an office party
when a martini or two can trick your brain into thinking you've
already done some social bonding? Drugs tell users' brains that
they've just done an important, fitness-enhancing task.

Ultimately, however, the powerful urge to use and reuse is provided
by brain biology that evolved because it maximized survival. Seen
this way, we're all born addicts. Substance addiction and behavioral
addiction are linked. Their common language is in the shared
neurocircuitry that rewards fitness-promoting behaviors.

Consider the most common behavioral addictions from an evolutionary
perspective. Sex. Binge eating. Exercise. Working. They are
exceedingly fitness enhancing.

Connecting brain-rewarding behaviors to increased survival allowed
me to rethink technological "addictions" like video gaming,
e-mailing and social networking. Our smartphones, Facebook pages and
Twitter feeds profoundly combine the things that matter most to
animals competing to survive: a social network, access to mates, and
information about predatory threats.

Understanding the comparative biology and evolutionary origins of
addiction can improve how we understand this disease and its
sufferers. First, individual humans vary greatly in their
vulnerability to addiction. So do animals, from mammals to worms. In
addition, human and animal data both suggest that the younger the
animal is at the first exposure to an external drug, the more likely
it is to become addicted and responsive to that drug in the future.
This is a very important point.

In the United States, we've tried Prohibition and "just say no"
campaigns. We've set the drinking age at 21 and the illegal drug use
age at never. None of these interventions has completely stopped
teenagers from going after what they want.

But the evidence suggests that it's wise for parents to try harder
to delay their children's first exposures and, perhaps, to teach
them natural ways of achieving those chemical rewards: through
exercise, physical and mental competitions, or "safe" risk-taking,
like performing.

Substance abusers can learn healthy behaviors that provide the same
(albeit less potent) good feelings they used to seek from a bottle,
a pill or a needle. In fact, that may be what makes some rehab
programs so effective for certain addicts. The behaviors these
programs encourage--socializing, seeking companionship,
anticipating, planning and finding purpose--are all part of an
ancient, calibrated system that rewards survival behaviors with
drugs from an animal's inborn pharmacy.

Fat Planet

ALTHOUGH I'm a cardiologist, some days I feel more like a
nutritionist. Patients, family members and friends frequently ask
me, "What should I be eating?" We all know by now that choosing the
wrong foods and carrying extra weight on our bodies can make us

But humans aren't the only animals on our planet who get fat. In the
wild, animals as varied as birds, reptiles, fish and even insects
regularly gain--and then take off--weight. Closer to home,
nearly half of our pet dogs, cats, even horses and birds are now
overweight or obese, despite the low-carb, feline "Catkins" diet,
canine liposuction and increased exercise for bird "perch potatoes."
With our pets' excess pounds has come a familiar suite of obesity-
related ailments: diabetes, cardiovascular problems, musculoskeletal
disorders, glucose intolerance, some cancers and possibly high blood
pressure. They're familiar because we see nearly identical problems
in obese human patients.

I'd long assumed that wild animals stayed effortlessly lean and
healthy. I'd always thought that wild animals ate until they were
full and then prudently stopped. But in fact, given the chance, many
wild fish, reptiles, birds and mammals overindulge. Sometimes
spectacularly so. Abundance plus access--the twin downfalls of
many a human dieter--can challenge wild animals, too.

Although we may think of food in the wild as hard to come by, at
certain times of the year and under certain conditions, the supply
may be unlimited. Many gorge, stopping only when their digestive
tracts literally cannot take any more. Tamarin monkeys have been
seen to eat so many berries in one sitting that their intestines are
overwhelmed and they soon excrete the same whole fruits they
recently gobbled down.

Mark Edwards, an animal nutrition expert, told me, "We're all
hard-wired to consume resources in excess of daily requirements. I
can't think of a species that doesn't." Wild animals can get fat
with unfettered access to food.

Of course, animals also fatten normally--and healthily--in
response to seasonal and life cycles. Remarkably, it is the
landscape around an animal that determines whether its weight stays
steady or rises.

And nature imposes its own "weight-maintenance plan" on wild
animals. Cyclical periods of food scarcity are typical. Threats from
predators limit access to food. Weight goes up, but it also comes
down. If you want to lose weight the wild animal way, decrease the
abundance of food around yourself and interrupt your access to it.
And expend lots of energy in the daily hunt for food. In other
words: change your environment.

Looking across the species divide and seeing weight gain in a
broader context forces us to consider factors beyond the "diet and
exercise" dogma. Even without an assist from 32-ounce sodas, the
yellow-bellied marmots in the Rockies, blue whales off the coast of
California and country rats in Maryland have gotten steadily
chubbier in recent years. The explanation might lie in the
disruption of circadian rhythms. Of the global dynamics controlling
our biological clocks--including temperature, eating, sleeping and
even socializing--no "zeitgeber" is more influential than light.

New research suggests that when, and how much, light beams through
your eyes may play a quiet and unrecognized role in determining your
dress or pants size. And the breaking up of light-dark cycles may be
a culprit. Light pollution from suburban sprawl, big-city skyglow,
electronic billboards and stadium lights has brightened our planet.
A rodent study published in the Proceedings of the National Academy
of Sciences showed that mice housed with constant light--whether
bright or dim--had higher body mass indexes (B.M.I.'s) and blood
sugar levels than mice housed with standard cycles of dark and

Another invisible weight driver is housed within our own abdomens:
the trillions of microscopic organisms that live in our guts. This
world is called the microbiome, and it is colonized by two dominant
groups of bacteria: the Firmicutes and the Bacteroidetes. In the
mid-2000s, some scientists made an interesting observation. They
found that obese humans had a higher proportion of Firmicutes in
their intestines. Lean humans had more Bacteroidetes. As the obese
humans lost weight over the course of a year, their microbiomes
started looking more like those of lean individuals--with
Bacteroidetes outnumbering Firmicutes.

When the researchers looked at mice, they found the same thing.
Although not all research has replicated those results, if that
observation turns out to be true, it means that a booming Firmicute
colony might help harvest, say, 100 calories from one person's
apple. That person's friend may have a dominant Bacteroidete
population that would extract only 70 calories from the same apple.
This could be one factor in why your co-worker can eat twice as much
as everyone else but never seems to gain weight. The power of the
microbiome is well known to the veterinarians who oversee the care
of animals we make fat on purpose: livestock. Nowadays, it's common
for factory farming operations to administer antibiotics to food
animals from 1,500-pound steers to one-ounce baby chicks. The effect
of those antibiotics on the living colonies of gut bugs in the
animals' intestines may inform human obesity research.

Antibiotics don't kill just the bugs that make animals sick. Simply
by giving antibiotics, farmers can fatten their animals using less
feed. One hypothesis is that by changing the animals' gut
microflora, antibiotics create an intestine dominated by colonies of
microbes that are calorie-extraction experts. Anything that alters
gut flora, including but not limited to antibiotics, has
implications not only for body weight but for other elements of our
metabolism, such as glucose intolerance, insulin resistance and
abnormal cholesterol.

Modern, affluent humans have created a continuous eating cycle, a
kind of "uniseason." Our food is stripped of microbes, and we remove
more while scrubbing off dirt and pesticides. Because we control it,
the temperature is always a perfect 74 degrees. Because we're in
charge, we can safely dine at tables aglow in light long after the
sun goes down. All year round, our days are lovely and long; our
nights are short.

As animals, we find this single season an extremely comfortable
place to be. But unless we want to remain in a state of continual
fattening, with accompanying metabolic diseases, we will have to pry
ourselves out of this delicious ease.


PROBABLY our era's most iconic form of human self-harm, seemingly
tailor-made for suburban-parent hand-wringing and tabloid ogling, is
cutting. Its name says it all, but in case you don't know: it means
taking something sharp--maybe a razor blade, scissors, broken
glass or a safety pin--and slicing it across your skin to draw
blood and create wounds. Psychiatrists call cutters "self-injurers"
to include the whole range of inventive ways people dream up to hurt
themselves. Some burn themselves on purpose with cigarettes,
lighters or teakettles. Others bruise their skin by banging,
punching or pinching themselves. Those with trichotillomania rub and
rip out hair on their heads, faces, limbs and genitals. Some are
swallowers, ingesting objects like pencils, buttons, shoelaces or
silverware. We see this particular method a lot in prisons.

You may think self-injury occurs only in edgy subcultures or the
seriously mentally ill. But my psychiatrist colleagues say it's
sweeping through the general population. Why? A 22-year-old woman
posting on a university blog put it this way: "I began cutting my
arms at the age of 12... I think I could best describe the feeling I
get as total bliss. It relaxes me."

Bliss? Relaxation? Relief? Even after years of psychiatry training
and two decades around a hospital, I still think this sounds
incredible. But cutters and their therapists say it's true. And they
confirm that most self-injurers are not suicidal. But as to why they
do it, the short answer is that we don't really know.

I decided to see what insights a zoobiquitous approach could add.

A friend of mine once took her cat to the vet assuming it had a skin
affliction that was causing all the hair to fall off its legs,
revealing red, oozing sores. After some tests to rule out parasites
and systemic diseases, her vet said her pet was a "closet licker."
It's a common diagnosis for house cats, sometimes called psychogenic
alopecia. The cat was injuring itself with no clear physical
trigger, in a way that was reminiscent of a human cutter alone in
her room.

Owners of golden retrievers, Labrador retrievers, German shepherds,
Great Danes, and Doberman pinschers will probably recognize a
condition that often affects those breeds--in which they
obsessively lick and gnaw at their own bodies. The open sores they
create can cover the entire surface of a limb or the base of the

"Flank biters" are horses that violently nip at their own bodies,
drawing blood and reopening wounds.

The owners of these horses, like parents who discover their teenager
is cutting, are often confused and heartbroken by the behavior,
which can include bursts of violent spinning, kicking, lunging and

When owners bring in pets who circle furniture for hours, do back
flips to the point of physical exhaustion or rub their skin to the
point of breakage and bleeding, veterinarians sometimes describe
these behaviors as "stereotypies." Many of the compulsive behaviors
seen in horses, reptiles, birds, dogs and humans share core clinical
features, including the potential to cause suffering and profoundly
disrupt a patient's life. But many also share an intriguing
connection to cleaning activities.

You've probably heard about the repetitive hand washing practiced by
many sufferers of obsessive-compulsive disorder. Similarly, a
stressed cat may go overboard with a feline's cleaning tool of
choice, its raspy tongue. Veterinarians have come up with a
colloquial term that cuts right to the heart of what's going on
here. They call it, simply, "overgrooming."

Grooming is as basic an activity for many creatures as eating,
sleeping and breathing. Evolution probably favored nature's neat
freaks because they were the ones with fewer parasites and

Grooming plays a vital role in the social structure of many animal
groups, and it feels good. There's also a more private form of
grooming--small behaviors that all but the most virtuous of us
engage in all the time and often unconsciously. In general, they're
innocent enough, but given the choice, we definitely wouldn't want
to show them in public or watch other people do them.

Are your cuticles smooth or are there some rough edges begging to be
picked or nibbled off? Are you twirling a lock of hair around your
finger, twisting your eyebrows, stroking your own cheek, massaging
your own scalp? Studies looking at hair pulling, scab picking and
nail biting all point to a calm, trancelike state that typically
accompanies these small, automatic, self-soothing activities.

Perhaps the fingers playing with your hair sometimes have the urge
to pull a strand out. There's that slight tension as the root clings
to the follicle gently tug harder ... and a little harder
...until finally, there's that short, sharp sting and the hair
releases. Humans rely on this release-relief loop throughout the
day. We may rub, pull, nibble or squeeze a little more when we're
stressed, but for most of us the behavior never escalates. But for
some people the need for that feeling of release and relief is so
strong that they seek extreme levels of it. Self-harm is truly
grooming gone wild.

In a way, self-harmers are actually self-medicators. That's because,
paradoxically, both pain and grooming cause the body to release
natural opiates, such as endorphins, the same brain chemicals that
give marathoners their runner's high.

The typical middle-class teen is a little like the horse alone in
its stall, with most of its needs provided in easy-to-digest chunks.
He's left with lots of extra time and few activities as invigorating
as a daily struggle for survival. Zookeepers make animals forage to
avoid boredom. Should we explore getting teens involved in growing
and preparing their own foods, an activity that can produce feelings
of profound calm and purpose?

All of us--from full-blown cutters to secret hair pluckers and
nail biters--share our grooming compulsions with animals. Grooming
represents a hard-wired drive, one that's evolved over millions of
years with the positive benefits of keeping us clean and binding us

Our essential connection with animals extends from body to behavior,
from psychology to society. This calls for physicians and patients
to join veterinarians in thinking beyond the human bedside to
barnyards, oceans and skies.

Barbara Natterson-Horowitz is a cardiology professor at U.C.L.A. and
Kathryn Bowers is a writer. This essay is adapted from their
forthcoming book "Zoobiquity: What Animals Can Teach Us About Health
and the Science of Healing," which is told from the doctor's point
of view.
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