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e never heard of this in seals. However=2C the review article you su --bcaec51a75985d103d049f8d72eb Content-Type: text/plain; charset=ISO-8859-1 Fritz and all, I'd say that scenario is unlikely. Two tubes lead from the back of your throat, your trachea (carries air to/from your lungs) and your oesophagus (carries food and water usually only in one direction, towards your stomach). The trachea wall is supported by rings of cartilage...go ahead, feel under your Adam's apple for them...I'll wait... ;). Were it not for a conveniently-placed epiglottis, food (or rocks) could easily enter the trachea during swallowing, or perhaps even by wave action. However, that epiglottis is there. The oesophagus is unlike the trachea in that unless it is in the process of swallowing, it is a collapsed tube. Its wall is invested with muscle which propels the food towards (or rarely away from) the stomach. Should a rock be so lucky to get washed in to the mouth, past the teeth and to the back of the throat, it would have to be forced into the oesophagus. One rock I could understand, but not all that I found. The first rock would simply jam in the oesophagus, preventing any more from getting in. Randy _________________________________ RF Lauff Way in the boonies of Antigonish County, NS. On 28 March 2011 13:10, Fritz McEvoy <fritzmcevoy@hotmail.com> wrote: > Hi Randy and All, > I don't have any expertise to offer but I have an off the wall > suggestion. Could this have been a post mortem event caused by tides washing > gravel and small stones into an open mouth and down the throat? > I realize this would be exceedingly rare occurrence; if it's possible at > all; but under very odd circumstances (open mouth & just right body position > in just the right type of tidal zone) it might occur; providing the throat > was open. > I have a very thick skin so if I'm out to lunch on this feel free to > mock. All the best. > Fritz McEvoy > Sunrise Valley, CB > ------------------------------ > From: randy.lauff@gmail.com > Date: Mon, 28 Mar 2011 12:47:40 -0300 > Subject: Re: [NatureNS] seal eating rocks > To: naturens@chebucto.ns.ca > > > Thanks James. > > In general, carnivores don't use stones to grind food since meat is so > easily digestible - anything swallowed can be acidified and enzyme-treated > for digestion; bile helps with the prey's fats in the small intestine. I am > aware of the debate of the functions of gut stones in crocodiles...ballast > versus grinding (perhaps both...since crocs swallow bones), but have never > heard of this in seals. However, the review article you supplied indicates > that eared seals, but not earless seals (like the Harbour Seal), have them. > > Additionally, this animal had a *full* stomach of stone and gravel, and the > oesophagus was full, too, suggesting something out of the ordinary. At the > time, I glanced at the teeth and didn't notice anything unusual - I'll look > in more detail when I prep out the head. > > Randy > _________________________________ > RF Lauff > Way in the boonies of > Antigonish County, NS. > > > On 28 March 2011 11:17, James Churchill <jameslchurchill@gmail.com> wrote: > > hey Randy, > > found some theories on stress ( > http://www.dem.ri.gov/news/2007/pr/0423071.htm), consequence of eating > snow/ice on beach ( > http://www.mysticaquarium.org/animals-and-exhibits/species-of-the-month/706-harp-seal) > ... > > Wikipedia also had some thoughts on Gastroliths... as a natural behaviour, > for food grinding or for ballast... > > And finally an article in Phil. Trans. R. Soc. B comparing these two > theories of gastrolith function (grinding vs. ballast) in marine tetrapods > (http://www.jstor.org/pss/55808) > > Any other clues Randy, like condition of the seal's teeth or whether the > stones appeared to be recently ingested (local rocks) or worn/polished? (I > suppose full esophagus suggests recent...?) > > Be interested to hear what you find out!! > > Cheers > > James. > > > On Mon, Mar 28, 2011 at 10:13 AM, Helene Van Doninck < > helene.birdvet@gmail.com> wrote: > > Some animals can exhibit "pica", or the ingestion of abnormal things if > they have metabolic issues or blood dyscrasias...just a thought > Helene > > On 2011-03-28 8:54 AM, "Randy Lauff" <randy.lauff@gmail.com> wrote: > > The surprise animal at the end of this year's Comparative Vertebrate > Anatomy class was a Harbour Seal. The seal was found live in a "not good" > condition at Cribbons Point, Ant. Co., last semester. Shortly thereafter, it > died and was graciously delivered to me by DFO. > > Last week, my students and I opened it up and found that its stomach and > oesophagus were both full of stones...up to a bit bigger than golf ball > size. Any ideas why a seal would eat rocks? My only guess was > desperation...for some reason, it could have been hungry, but couldn't catch > any thing? It had a decent layer of blubber, so I don't think it was > starving. Nothing else seemed wrong with it, though I am no vet. > > Thoughts? > Randy > _________________________________ > RF Lauff > Way in the boonies of > Antigonish County, NS. > > > > > -- > James Churchill > Kentville, Nova Scotia > jameslchurchill@gmail.com > home: (902) 681-2374 > > > --bcaec51a75985d103d049f8d72eb Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Fritz and all,<div><br></div><div>I'd say that scenario is unlikely. Tw= o tubes lead from the back of your throat, your trachea (carries air to/fro= m your lungs) and your oesophagus (carries food and water usually only in o= ne direction, towards your stomach).</div> <div><br></div><div>The trachea wall is supported by rings of cartilage...g= o ahead, feel under your=A0Adam's=A0apple for them...I'll wait... ;= ). Were it not for a conveniently-placed epiglottis, food (or rocks) could = easily enter the trachea during swallowing, or perhaps even by wave action.= However, that epiglottis is there.</div> <div><br></div><div>The oesophagus is unlike the trachea in that unless it = is in the process of swallowing, it is a collapsed tube. Its wall is invest= ed with muscle which propels the food towards (or rarely away from) the sto= mach. Should a rock be so lucky to get washed in to the mouth, past the tee= th and to the back of the throat, it would have to be forced into the oesop= hagus. One =A0rock I could understand, but not all that I found. The first = rock would simply jam in the oesophagus,