[NatureNS] seal eating rocks

From: Fritz McEvoy <fritzmcevoy@hotmail.com>
To: NS NATURE <naturens@chebucto.ns.ca>
Date: Mon, 28 Mar 2011 13:10:08 -0300
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Hi Randy and All=2C
   I don't have any expertise to offer but I have an off the wall suggestio=
n. Could this have been a post mortem event caused by tides washing gravel =
and small stones into an open mouth and down the throat?=20
   I realize this would be exceedingly rare occurrence=3B if it's possible =
at all=3B but under very odd circumstances (open mouth & just right body po=
sition in just the right type of tidal zone) it might occur=3B providing th=
e throat was open.
   I have a very thick skin so if I'm out to lunch on this feel free to moc=
k. All the best.
                             Fritz McEvoy
                               Sunrise Valley=2C CB

From: randy.lauff@gmail.com
Date: Mon=2C 28 Mar 2011 12:47:40 -0300
Subject: Re: [NatureNS] seal eating rocks
To: naturens@chebucto.ns.ca

Thanks James.=20


In general=2C carnivores don't use stones to grind food since meat is so ea=
sily digestible - anything swallowed can be acidified and enzyme-treated fo=
r digestion=3B 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)=2C but have nev=
er heard of this in seals. However=2C the review article you supplied indic=
ates that eared seals=2C but not earless seals (like the Harbour Seal)=2C h=
ave them.


Additionally=2C this animal had a *full* stomach of stone and gravel=2C and=
 the oesophagus was full=2C too=2C suggesting something out of the ordinary=
. At the time=2C 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=2C NS.



On 28 March 2011 11:17=2C James Churchill <jameslchurchill@gmail.com> wrote=
:

hey Randy=2C=20

found some theories on stress (http://www.dem.ri.gov/news/2007/pr/0423071.h=
tm)=2C consequence of eating snow/ice on beach (http://www.mysticaquarium.o=
rg/animals-and-exhibits/species-of-the-month/706-harp-seal) ...

Wikipedia also had some thoughts on Gastroliths... as a natural behaviour=
=2C for food grinding or for ballast...

And finally an article in Phil. Trans. R. Soc. B comparing these two theori=
es of gastrolith function (grinding vs. ballast) in marine tetrapods=20
(http://www.jstor.org/pss/55808)

Any other clues Randy=2C 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.=20






On Mon=2C Mar 28=2C 2011 at 10:13 AM=2C Helene Van Doninck <helene.birdvet@=
gmail.com> wrote:

Some animals can exhibit "pica"=2C or the ingestion of abnormal things if t=
hey have metabolic issues or blood dyscrasias...just a thought
Helene





On 2011-03-28 8:54 AM=2C "Randy Lauff" <randy.lauff@gmail.com> wrote:

The surprise animal at the end of this year's Comparative Vertebrate Anatom=
y class was a Harbour Seal. The seal was found live in a "not good" conditi=
on at Cribbons Point=2C Ant. Co.=2C last semester. Shortly thereafter=2C it=
 died and was graciously delivered to me by DFO.=20


Last week=2C 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 siz=
e. Any ideas why a seal would eat rocks? My only guess was desperation...fo=
r some reason=2C it could have been hungry=2C but couldn't catch any thing?=
 It had a decent layer of blubber=2C so I don't think it was starving. Noth=
ing else seemed wrong with it=2C though I am no vet.


Thoughts?
Randy_________________________________
RF Lauff
Way in the boonies of
Antigonish County=2C NS.


--=20
James Churchill
Kentville=2C Nova Scotia
jameslchurchill@gmail.com
home: (902) 681-2374


 		 	   		  =

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Hi Randy and All=2C<BR>&nbsp=3B&nbsp=3B I don't have any expertise to offer=
 but I have an off the wall suggestion.&nbsp=3BCould this&nbsp=3Bhave been =
a post mortem event caused by tides washing gravel and small stones into&nb=
sp=3Ban open&nbsp=3Bmouth&nbsp=3Band down the throat? <BR>
&nbsp=3B&nbsp=3B I realize this would be exceedingly rare occurrence=3B if =
it's&nbsp=3Bpossible at all=3B but under very odd circumstances (open mouth=
 &amp=3B just right body position in just the right type of&nbsp=3Btidal zo=
ne)&nbsp=3Bit might occur=3B providing the throat was open.<BR>&nbsp=3B&nbs=
p=3B&nbsp=3BI have a very thick skin so if I'm out to lunch on this feel fr=
ee to mock. All the best.<BR>
&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nb=
sp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=
=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B=
 Fritz McEvoy<BR>
&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nb=
sp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=
=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B&nbsp=3B=
&nbsp=3B&nbsp=3B Sunrise Valley=2C CB
<HR id=3DstopSpelling>
From: randy.lauff@gmail.com<BR>Date: Mon=2C 28 Mar 2011 12:47:40 -0300<BR>S=
ubject: Re: [NatureNS] seal eating rocks<BR>To: naturens@chebucto.ns.ca<BR>=
<BR>Thanks James.=20
<DIV><BR></DIV>
<DIV>In general=2C carnivores don't use stones to grind food since meat is =
so easily digestible - anything swallowed can be acidified and enzyme-treat=
ed for digestion=3B 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...ba=
llast versus grinding (perhaps both...since crocs swallow bones)=2C but hav=
e never heard of this in seals. However=2C the review article you su