--- "billsnape" wrote:---------
> but (as you infer) pica can't be ruled out as the reason
> the sow is chewing stones.

Well, I said that stone-eating in outdoor sows is a "pica-like"
activity and went on to ascribe it to "frustrated natural
exploratory/creative drives are played out in the repetitive mouthing
and even swallowing of stones". See...
http://www.ars.usda.gov/research/publications/publications.htm?seq_no_115=205117
"...stone chewing represents thwarted foraging behaviour and may be a
form of stereotypic behavior as it is most prevalent in relatively
barren environments of bare earth paddocks. Horrell & A¿Ness
hypothesize that it is a function of boredom or a coping response to
stress."

>> Sucking an iron bar or stable door might equally be pica.

Here is a video, Bill, showing the horrific conditions in which bar-
biting occurs...
http://uk.youtube.com/watch?v=5QM44d5wgF8
Fortunately such housing is now banned in the UK and bar-biting is
now rarely seen. Bar biting is most often seen, as in this film clip,
when the sows are very excited e.g. when they hear the sounds that
signal food is about to be served. In these housing conditions
pregnant sows were (and still are in some countries) often only fed
once a day, whereas naturally they would spend most of their day
foraging and rooting for food. Under such awfully boring
housing/environment conditions pigs become quite manic-depressive
(bipolar) - lying around depressed much of the time, then over-excited when at
last the tedium (and long wait for food) is broken.

On this webpage:
http://www.pighealth.com/MEDIA/P/BOOKS/BEHAVBKS.HTM
You can see a film clip of sows' natural and powerful innate drives
for exploratory, investigative and rooting behaviour. When these
intrinsic energies are frustrated, it is little surprise that this
frustration gets expressed in bizarre forms such as stone-chewing,
bar-biting and stereotypical "weaving" movement patterns (like we see
in caged wild animals in boring, restricted environments).

"Depraved" Appetites
----------------------

I can't add much to the discussion on sugar-craving, except to say
don' forget that our stone-age ancestors also had a penchant for
sugar-rich wild honey, as well as fruit. Also, blood sugar (glucose)
quickly rises under acute stress, but this (and more especially the
consumption of high-sugar snacks to fuel stress-induced blood glucose
changes) is often followed by a rebound sharp drop in blood sugar
which can bring lethargy and more sugar-craving. In this way (similar
to using smoking as a way to relax), sugar snacking can insatiably
create more desire for more sugar intake - feeding on itself to
become an addiction.

Re: "Pica" (i.e. depraved/abnormal appetite for something unusual,
rather than an excessive desire [craving] for a normal dietary
constituent)....
A veterinary colleague of mine had a dog who, as he became elderly
and developed arthritis, also developed a penchant for consuming the
wild herb Lady's Bedstraw (Cleavers, Goosegrass genus). She was
puzzled by this until she found that this plant contains an anti-
inflammatory chemical called Asperuloside. It was quite amazing how
this dog would seek out and scoff this herb, which I have never seen
a dog eat before, or since. The dog's unusual appetite (Pica) for
this herb COULD be satisfied, but would return on subsequent days,
and the ingestive behaviour DID NOT take a closely-regimented form of
expression - i.e. it was quite different from the "stereotypical"
repetitive oral behaviours described below.

Cindy Engels gives some good examples of "pica" (depraved appetite)
phenomena in animals which seem to be linked to mineral deficiencies,
but stereotypies occur in quite different circumstances and actually
take a quite different form in that..

a) they are insatiable (unless the environment is enriched - see
below)
b) they often appear purposeless from a consumption point of view
i.e. the mouthing movements are more important than ingestion of
substances.
c) as I mention before there is a kind of "religiously-rigid"
regimentation of the movements.

Crib-biting in Horses
-----------------------

Here is a film clip of a horse crib-biting..
http://uk.youtube.com/watch?v=NED5KM1diCU
The stupid owners comment...
"After a meal of a nice carrot or two, this horse likes to gnaw on
the fence and make a funny grunting sound. Enjoy!"

Bastards!

The grunting sounds by the way are a sign of wind-sucking, part of
the mechanism for drawing air into the stomach - leading to digestive
disturbances. Crib-biting is damaging to a horse's teeth (they are
not designed for biting wood) as well as fences and stable fittings.

As with sows bar-biting, horses will often crib-bite just before or
after meals (though also at other times when frustrated or bored).
Like pigs, horses would naturally spend most of their day seeking out
and ingesting food. Easily acquired, high nutrient density diets
leave them bored and in some cases, their stomach will still feel
empty. Their frustration goes into a range of what used to be
called "stable vices" but are now regarded as frustration-driven
stereotypical, self-tranquilising (via endorphins) behaviors.

Environment Enrichment
----------------------------

> Fish can commonly be observed sucking stones and spitting them out.
> The behaviour is common to wild and captive fish so cannot (or at
least cannot always)
> be attributed to the frustration of living in a goldfish-bowl.

A fish living in water seems to me to be a very different situation
from a specific mammal living on a specific land environment, so I'm
afraid I can't accept this as a valid analogy, Bill.

There are some good research reviews on mammalian stereotypical
behaviour patterns and their causes in this book:
"Physiology and Behaviour of Animal Suffering"
http://www.pighealth.com/reviews/suffering.htm

Prevention and treatment of stereotypical behaviours is reviewed here:
"Environmental Enrichment for Captive Animals"
http://www.Amazon.co.uk/exec/obidos/ASIN/0632064072/pigdiseaseinfo0c

Implications for Over-eating/Overweight
--------------------------------------------

I have to say that one of the main times I will "unhealthy snack" or
drink calorie-rich drinks terribly, is when I have a
tedious/boring/uninspiring task to do that is not physically
expressive of how I am feeling. In days gone by I would have smoked
or chewed gum at these times when my natural inclinations/motivations
were being thwarted.

In a similar vein, I often see shelf-stackers in my local supermarket
hurling food aggressively onto the shelves in a manner that speaks of
bored frustration. They are able (so long as the supervisor isn't
watching!) to act out their frustration at being financially
restricted to a job which does not meet Chopra's 7th law. In my case,
I displace my frustration into oral behaviour.

It's interesting that our ape cousins do a lot of mouth-
chewing/champing movements when frustrated (the Brooke Bond TV chimps
got into trouble over this - the cute voiceovers were using
frustration mouth movements). Similarly when under stress, we are
prone to grind our teeth during sleep, leading to dental problems. So
oral activity does seem to be a common mammalian route for expressing
or displacing frustrated innate drives.

The second most common trigger for my own unhealthy appetites is when
I am watching TV or a computer screen - situations in which my energy
system is stimulated, but physical expression/release is inhibited.


What triggers do other people in this group have for their unhealthy appetites?


Best wishes to everyone

Mike