/LMAR=0/XLINE=3/FONT#0=BAXL30/FONT#1=BAXM30/FONT#2=BASB30/FONT#3=SUB/FONT#4=SUP/FONT#5=BASL35/FONT#6=NGR25/FONT#7=MATH25/FONT#8=FIX25



␈↓ α∧␈↓α␈↓ ¬.MATERIALS AND METHODS

␈↓ α∧␈↓␈↓ αTThe␈αexperimental␈αanimals␈α
used␈αwere␈αlocally␈α
trapped␈αshrews␈αof␈α
three␈αspecies,␈αthe␈α
Wandering
␈↓ α∧␈↓Shrew␈α(␈↓↓Sorex␈αvagrans␈↓),␈αof␈αwhich␈αI␈αhad␈αone;␈αthe␈αTrowbridge␈αShrew␈α(␈↓↓Sorex␈αtrowbridgii␈↓),␈αof␈αwhich␈αI
␈↓ α∧␈↓had␈α⊃four,␈α⊂and␈α⊃the␈α⊃Water␈α⊂Shrew␈α⊃(␈↓↓Sorex␈α⊃palustris␈↓),␈α⊂of␈α⊃which␈α⊂I␈α⊃had␈α⊃seven.␈α⊂ (See␈α⊃Fig.␈α⊃7).␈α⊂ The
␈↓ α∧␈↓Wandering␈αShrews␈αranged␈αin␈αweight␈αfrom␈α4.9␈αto␈α6.9␈αgrams,␈αthe␈αTrowbridge␈αShrews␈αranged␈αfrom
␈↓ α∧␈↓3.1␈αto␈α6.5␈α
grams,␈αand␈αthe␈α
Water␈αShrews␈αranged␈αfrom␈α
8.6␈αto␈α15.7␈α
grams.␈α Literature␈αweights␈αfor␈α
the
␈↓ α∧␈↓adults␈α
of␈α
the␈α
species␈α
are␈α
7␈α-␈α
8␈α
grams,␈α
7␈α
grams,␈α
and␈αup␈α
to␈α
18␈α
grams,␈α
respectively.␈α
 (Ingles␈α1964).␈α
 All
␈↓ α∧␈↓the␈αanimals␈αwere␈αtrapped␈α
in␈αsand␈αor␈αmoss,␈α
no␈αmore␈αthan␈αeight␈α
meters␈αfrom,␈αand␈αcommonly␈α
within
␈↓ α∧␈↓one␈αmeter␈αof␈αthe␈αedge␈αof␈αthe␈αwater.␈α The␈αtrapping␈αsites␈αwere␈αalong␈αthe␈αZigzag␈αRiver␈αon␈αthe␈αlower
␈↓ α∧␈↓slopes␈α∞of␈α∂Mt.␈α∞Hood,␈α∂near␈α∞the␈α∞Kiwanis␈α∂Camp␈α∞Road.␈α∂ The␈α∞Vagrant␈α∞Shrew␈α∂was␈α∞caught␈α∂by␈α∞hand
␈↓ α∧␈↓running␈αthrough␈αopen␈αgrassy␈α
sand␈αdunes␈αnear␈αshrubs␈α
at␈αLedbetter␈αPoint,␈αWashington.␈α
 The␈αrest
␈↓ α∧␈↓of␈α∞the␈α∞animals␈α∞were␈α∂caught␈α∞using␈α∞the␈α∞sunken␈α∞bucket␈α∂technique,␈α∞which␈α∞consisted␈α∞in␈α∞this␈α∂case␈α∞of
␈↓ α∧␈↓burying␈αa␈αone␈αgallon␈αjar␈αso␈αthat␈αits␈αopen␈αmouth␈αis␈αflush␈αwith␈αthe␈αsurface␈αof␈αthe␈α
ground.␈α (Other
␈↓ α∧␈↓animals␈α∂which␈α∂fall␈α∂in␈α∂are␈α⊂able␈α∂to␈α∂jump␈α∂out␈α∂not␈α∂the␈α⊂case␈α∂with␈α∂shrews).␈α∂ The␈α∂area␈α∂was␈α⊂a␈α∂thick
␈↓ α∧␈↓Douglas␈αFir␈αand␈αCedar␈αforest,␈αwith␈αsome␈αhuman␈αdisturbance␈αin␈αthe␈αform␈αof␈αcamping.␈α The␈αtraps
␈↓ α∧␈↓were␈α
set␈α
in␈α
the␈α
evening␈α
and␈α
checked␈α∞at␈α
two-hour␈α
intervals␈α
during␈α
the␈α
night,␈α
or,␈α
later,␈α∞just␈α
after
␈↓ α∧␈↓nightfall and just after sunrise.

␈↓ α∧␈↓␈↓ αTShrews␈α∀were␈α∪housed␈α∀in␈α∪ten-gallon␈α∀and␈α∪fifteen-gallon␈α∀tanks␈α∪lined␈α∀with␈α∪bark␈α∀dust.␈α∪ A
␈↓ α∧␈↓constant␈α∞supply␈α∂of␈α∞fresh␈α∞water␈α∂was␈α∞available.␈α∂ Cardboard␈α∞paper␈α∞towel␈α∂tubes␈α∞were␈α∂provided␈α∞for
␈↓ α∧␈↓hiding␈αand␈αsleeping,␈αas␈αwere␈αdry␈αleaves.␈α They␈αwere␈αfed␈αmealworms␈αobtained␈αfrom␈αthe␈αSure-Live
␈↓ α∧␈↓Mealworm␈αCompany␈αof␈α
Paramount,␈αCalifornia␈αand/or␈α
shrimp-flavored␈αcat␈αfood␈αmanufactured␈α
by
␈↓ α∧␈↓the␈αNew␈αEngland␈αFish␈αCompany␈αof␈αSeattle,␈αWashington.␈α This␈αfood␈αwas␈αconstantly␈αavailable␈αin␈α
a
␈↓ α∧␈↓low␈α∞dish.␈α∂ Food␈α∞was␈α∂supplied␈α∞in␈α∞excess␈α∂and␈α∞the␈α∂amount␈α∞eaten␈α∞daily␈α∂was␈α∞weighed.␈α∂ The␈α∞shrews
␈↓ α∧␈↓themselves were also weighed daily.

␈↓ α∧␈↓␈↓ αTThe␈α∩first␈α∩experimental␈α∩cage␈α∩used␈α∩was␈α∩a␈α∩wooden␈α∩cage␈α∩with␈α∩a␈α∩wire␈α∩top,␈α∩which␈α∩was␈α∩90
␈↓ α∧␈↓centimeters␈α∞long,␈α∞32␈α∞centimeters␈α∞wide,␈α∞and␈α∂32␈α∞centimeters␈α∞high.␈α∞ Later␈α∞a␈α∞wooden␈α∞cage␈α∂was␈α∞built
␈↓ α∧␈↓which␈αwas␈α2.5␈αmeters␈αlong,␈α1.25␈αmeters␈αwide,␈αand␈α32␈αcm.␈αhigh.␈α It␈αalso␈αhad␈αa␈αwire␈αtop.␈α Bark␈αdust
␈↓ α∧␈↓lined␈α
the␈αbottom␈α
of␈α
the␈αcage␈α
to␈α
a␈αdepth␈α
of␈αup␈α
to␈α
about␈α12␈α
cm.␈α
 Prey␈αitems␈α
were␈αmealworms␈α
pinned
␈↓ α∧␈↓to␈αdried␈αpieces␈αof␈αpotato␈α(mealworm␈αfood)␈αor␈αto␈αcorks.␈α The␈αpotato␈αpieces␈αsometimes␈αwere␈αmarked
␈↓ α∧␈↓with␈α∞green␈α
food␈α∞coloring␈α
to␈α∞make␈α
them␈α∞easier␈α∞for␈α
the␈α∞experimenter␈α
to␈α∞find.␈α
 Being␈α∞pinned␈α∞to␈α
a
␈↓ α∧␈↓potato seldom harms a mealworm, and the shrew neatly removes them from the pin.

␈↓ α∧␈↓␈↓ αTThe␈α
idea␈αwas␈α
that␈αthe␈α
shrew,␈αwith␈α
a␈α
plentiful␈αsupply␈α
of␈αa␈α
less␈αdesirable␈α
food,␈αcatfood,␈α
would
␈↓ α∧␈↓be␈αplaced␈αin␈αa␈αsituation␈αwhere␈αit␈αcould␈αfind␈αthe␈αmore␈αdesirable␈αmealworms,␈αand␈αby␈αlearning␈αhow
␈↓ α∧␈↓to␈α∂find␈α⊂them␈α∂at␈α∂different␈α⊂densities␈α∂would␈α⊂display␈α∂a␈α∂functional␈α⊂response.␈α∂ An␈α⊂experimental␈α∂run
␈↓ α∧␈↓lasted␈αtwenty-four␈αhours.␈α A␈αsingle␈αshrew␈αwhich␈αappeared␈αin␈αgood␈αhealth,␈αwould␈αbe␈αplaced␈αin␈αthe
␈↓ α∧␈↓cage␈αwith␈αwater,␈αcat␈αfood,␈αtwo␈αhiding␈αtubes,␈αand␈αwhatever␈αarrangement␈αof␈αpotatoes␈αor␈αmealworms
␈↓ α∧␈↓with␈αpotatoes␈α
was␈αcalled␈αfor.␈α
 The␈αshrew␈αwas␈α
weighed␈αbefore␈α
and␈αafter␈αthe␈α
experiment,␈αas␈αwas␈α
the
␈↓ α∧␈↓food.␈α∞ Mealworms␈α∞were␈α∂buried␈α∞under␈α∞the␈α∂bark␈α∞dust␈α∞at␈α∞regular␈α∂intervals.␈α∞ Thus,␈α∞for␈α∂example,␈α∞a
␈↓ α∧␈↓density␈αof␈α16␈αmealworms/square␈αmeter␈αwould␈αrequire␈α50␈αmealworms␈αburied␈αapproximately␈α
25␈αcm
␈↓ α∧␈↓apart.





␈↓ α∧␈↓␈↓ ε|1␈↓ ∧



␈↓ α∧␈↓α␈↓ ε=RESULTS

␈↓ α∧␈↓␈↓ αTThe␈α∩results␈α∩were␈α∩consistently␈α∩a␈α∩disappointment.␈α⊃ I␈α∩was␈α∩unable␈α∩to␈α∩obtain␈α∩even␈α∩a␈α⊃single
␈↓ α∧␈↓functional␈α
response␈α
curve.␈α
 The␈α
first␈α
difficulty␈α
was␈α
the␈α
experimental␈α
cage.␈α
 The␈α
first␈α
cage␈α
used␈α
was
␈↓ α∧␈↓much␈α
to␈αsmall;␈α
it␈α
soon␈αdeveloped␈α
that␈α
there␈αwas␈α
really␈α
no␈αway␈α
a␈α
shrew␈αcould␈α
avoid␈αstumbling␈α
over
␈↓ α∧␈↓all␈αthe␈α
prey␈αitems␈α
in␈αthe␈α
course␈αof␈α
going␈αaround␈α
the␈αcage␈α
trying␈αto␈α
escape,␈αeven␈α
when␈αthe␈αdepth␈α
of
␈↓ α∧␈↓the␈αbark␈αdust␈αlayer␈αwas␈αincreased.␈α After␈αbuilding␈αa␈αsecond␈αmuch␈αlarger␈αcage,␈αslightly␈αlarger␈αthan
␈↓ α∧␈↓the␈αexperimental␈αcage␈αused␈αby␈αHolling␈α(1964)␈αin␈αsuccessfully␈αobtaining␈αfunctional␈αresponse␈αcurves
␈↓ α∧␈↓with␈α
deer␈αmice,␈α
the␈αdifficulties␈α
continued.␈α (There␈α
was␈αalso␈α
some␈αdelay␈α
owing␈αto␈α
the␈α
difficulty␈αof
␈↓ α∧␈↓catching␈αshrews␈αin␈αthe␈α
winter.)␈αThe␈αshrews␈αinvariably,␈αwhatever␈α
their␈αspecies,␈αfound␈αall␈α
the␈αprey
␈↓ α∧␈↓items,␈αor␈α
on␈αa␈αcouple␈α
of␈αoccasions,␈α
none␈αat␈αall.␈α
 On␈αthe␈α
occasions␈αwhen␈αthe␈α
shrew␈αfound␈α
none,␈αit
␈↓ α∧␈↓appeared␈α
that␈α
it␈α
had␈α
spent␈α
virtually␈α
all␈α
its␈α
time␈α
hiding␈α
in␈α
the␈α
nest␈α
tube␈α
-␈α
thus␈α
invalidating␈α
the␈α
test.
␈↓ α∧␈↓The␈α∂results␈α∂were␈α∂similar␈α∂for␈α∞shrews␈α∂which␈α∂had␈α∂not␈α∂been␈α∞in␈α∂the␈α∂experimental␈α∂cage␈α∂and␈α∞shrews
␈↓ α∧␈↓which␈αhad␈αbeen␈αaccustomed␈αto␈αthe␈αexperimental␈αcage␈αwith␈αpotatoes␈αwithout␈αmealworms␈αburied␈αin
␈↓ α∧␈↓it.␈α⊂ The␈α⊂level␈α⊂of␈α⊂bark␈α⊂dust␈α⊂was␈α⊂increased␈α⊂to␈α⊂make␈α⊂the␈α⊂prey␈α⊂more␈α⊂difficult␈α⊂to␈α⊂detect.␈α⊂ On␈α∂two
␈↓ α∧␈↓occasions␈α
a␈α
shrew␈α
took␈α
some␈α
but␈α
not␈α
all␈α
the␈α
prey.␈α In␈α
each␈α
case␈α
it␈α
was␈α
a␈α
first␈α
trial,␈α
with␈α
a␈αdensity␈α
of
␈↓ α∧␈↓16␈α∞mealworms/m␈↓∧2␈↓.␈α∞ In␈α∞one␈α∞case,␈α∞the␈α∞Water␈α
Shrew,␈α∞the␈α∞shrew␈α∞had␈α∞not␈α∞been␈α∞in␈α∞the␈α
experimental
␈↓ α∧␈↓cage␈α
beforehand,␈α
with␈α
potato␈αpieces␈α
buried␈α
in␈α
it.␈α In␈α
the␈α
first␈α
case,␈α
26␈αof␈α
the␈α
prey␈α
items␈αwere␈α
taken,
␈↓ α∧␈↓in␈α∞the␈α∞second,␈α∂27␈α∞were␈α∞taken.␈α∞ In␈α∂each␈α∞case,␈α∞in␈α∞all␈α∂subsequent␈α∞experiments,␈α∞no␈α∞matter␈α∂what␈α∞the
␈↓ α∧␈↓density of prey items, every single one was taken.

␈↓ α∧␈↓α␈↓ ε$DISCUSSION

␈↓ α∧␈↓␈↓ αTI␈αbelieve␈αthat␈αif␈αhigh␈αhad␈αkept␈αtrying␈αlong␈αenough␈α-␈αand␈αwho␈αknows␈αhow␈αlong␈α
that␈αmight
␈↓ α∧␈↓have␈α∂been␈α∂-␈α⊂I␈α∂would␈α∂have␈α⊂eventually␈α∂gotten␈α∂functional␈α∂response␈α⊂curves.␈α∂ Possibly␈α∂it␈α⊂would␈α∂be
␈↓ α∧␈↓necessary␈α∂to␈α∞use␈α∂a␈α∞naive␈α∂shrew␈α∞every␈α∂time.␈α∞ Possibly␈α∂the␈α∞reason␈α∂I␈α∞was␈α∂unable␈α∞to␈α∂get␈α∞functional
␈↓ α∧␈↓response␈α
curves␈α
was␈αsimply␈α
that␈α
the␈αtask␈α
itself␈α
was␈αtoo␈α
simple,␈α
and␈αhence␈α
there␈α
was␈αno␈α
opportunity
␈↓ α∧␈↓for␈αlearning␈αto␈αtake␈αplace.␈α If␈αthere␈αis␈αno␈αroom␈αfor␈αlearning,␈αone␈αshould␈αget␈αa␈αType␈αII␈αcurve.␈α It␈αis
␈↓ α∧␈↓worth␈αnoting␈αthat␈αwhen␈αC.S.␈αHolling␈αblindfolded␈αpeople␈αand␈αhad␈αthem␈αhunt␈αfor␈αsandpaper␈αdisks
␈↓ α∧␈↓on␈αa␈αtable␈αtop␈αby␈αpoking␈αabout␈αwith␈αa␈αfinger␈αtip,␈αhe␈αgot␈αvery␈αnice␈αpure␈αType␈αII␈αresponses.␈α And
␈↓ α∧␈↓this␈α
from␈α
a␈α
species␈α
notorious␈α
for␈α
its␈α
larning␈α
abilities!␈α
 Holling␈α
got␈α
a␈α
functional␈α
response␈αcurve␈α
from
␈↓ α∧␈↓a␈α
deer␈α
mouse␈α
under␈α
conditions␈α
almost␈α
identical␈α∞to␈α
the␈α
ones␈α
I␈α
used.␈α
 Possibly␈α
learning␈α
to␈α∞dig␈α
out
␈↓ α∧␈↓prey␈α∞items␈α
is␈α∞more␈α∞foreign␈α
to␈α∞a␈α
deer␈α∞mouse␈α∞than␈α
to␈α∞a␈α
shrew,␈α∞and␈α∞so␈α
more␈α∞learning␈α∞is␈α
involved.
␈↓ α∧␈↓Possibly␈α
the␈α
mealworms,␈α
which␈α
are␈α
capable␈α
of␈α
being␈α
fairly␈α
active,␈α
made␈α
noise␈α
or␈α∞were␈α
otherwise
␈↓ α∧␈↓obvious␈α
to␈α
the␈α
shrews,␈αas␈α
the␈α
cocoons␈α
used␈αby␈α
Holling␈α
might␈α
not␈αhave␈α
been.␈α
 Shrews␈α
have␈αbeen
␈↓ α∧␈↓observed␈α(when␈αthey␈αare␈αobserved)␈αrunning␈αalong,␈αunder␈αand␈αamong␈αleaf␈αlitter␈α-␈αit␈αmight␈αbe␈αthat
␈↓ α∧␈↓the␈αbark␈α
dust␈αwas␈αsufficiently␈α
similar␈αso␈α
that␈αtheir␈αregular␈α
foraging␈αpattern␈α
would␈αquickly␈αturn␈α
up
␈↓ α∧␈↓all␈αthe␈αmealworms␈αpresent.␈α Or,␈αas␈αis␈αquite␈αlikely,␈αthe␈αshrew␈αmay␈αbe␈αsuch␈αa␈αquick␈αlearner␈αthat␈αthe
␈↓ α∧␈↓cage␈αwas␈α
too␈αsmall␈α
to␈αallow␈α
a␈αsufficiently␈α
low␈αdensity␈α
of␈αmealworms␈α
to␈αcapture␈α
the␈αrising␈α
part␈αof
␈↓ α∧␈↓the curve.

␈↓ α∧␈↓␈↓ αTThere␈α⊃is␈α⊃no␈α⊂real␈α⊃evidence␈α⊃either␈α⊃way,␈α⊂and␈α⊃so␈α⊃anything␈α⊃I␈α⊂might␈α⊃say␈α⊃about␈α⊃the␈α⊂possible
␈↓ α∧␈↓foraging␈α
strategy␈αof␈α
shrews␈αwould␈α
be␈α
as␈αspeculative␈α
as␈αwhen␈α
I␈α
began.␈α The␈α
question␈αremains␈α
open.
␈↓ α∧␈↓One␈α
fruitful␈α∞approach␈α
migh␈α∞be␈α
an␈α∞attempt␈α
to␈α∞construct␈α
a␈α∞model␈α
specifically␈α∞designed␈α
to␈α∞look␈α
at
␈↓ α∧␈↓this question.




␈↓ α∧␈↓␈↓ ε|2␈↓ ∧



␈↓ α∧␈↓α␈↓ ε2APPENDIX

␈↓ α∧␈↓␈↓ αTIn␈αthe␈αcourse␈αof␈αmy␈αwork␈αon␈αthis␈αthesis,␈αI␈αlearned␈αa␈αnumber␈αof␈αthings␈αabout␈α
shrews␈αwhich
␈↓ α∧␈↓either␈αwere␈αnot␈αmentioned␈αin␈αthe␈αliterature,␈αor␈αwhich␈αI␈αfeel␈αcould␈αstand␈αmore␈αor␈αless␈α
emphasis.␈α I
␈↓ α∧␈↓included␈α
these␈αhere,␈α
because␈αI␈α
think␈αsome␈α
of␈αthem␈α
will␈αbe␈α
of␈αvalue␈α
to␈αanyone␈α
working␈αwith␈α
shrews
␈↓ α∧␈↓in the future; knowing them would have helped me considerably.

␈↓ α∧␈↓␈↓ αTIt␈α∂has␈α∂been␈α∂shown␈α∂(MacLeod␈α∂and␈α∂Lethrieq␈α∂1963;␈α∂Brown␈α∂1967)␈α∂that␈α∂the␈α∂"sunken␈α∞bucket"
␈↓ α∧␈↓technique␈α∂of␈α⊂trapping␈α∂is␈α⊂much␈α∂more␈α∂effective␈α⊂than␈α∂snap␈α⊂or␈α∂box␈α∂trapping.␈α⊂ It␈α∂seems␈α⊂that␈α∂most
␈↓ α∧␈↓animals␈αare␈αeasily␈αable␈αto␈αjump␈αout␈αof␈αthe␈αsunken␈αtraps,␈αbut␈αshrews'␈αhind␈αlegs␈αare␈αnot␈αthat␈α
strong,
␈↓ α∧␈↓and␈α∞shrews␈α
either␈α∞do␈α
not␈α∞enter␈α
other␈α∞traps␈α∞or␈α
are␈α∞too␈α
light␈α∞to␈α
trigger␈α∞them.␈α∞ Nevertheless␈α
many
␈↓ α∧␈↓authors␈α
refer␈α
to␈α
the␈α
possibility␈α
of␈α
catching␈α
shrews␈α
in␈α
ordinary␈α
traps,␈α
which␈α
led␈α
me␈α
to␈α
believe␈αit␈α
was
␈↓ α∧␈↓feasible␈α⊂if␈α∂not␈α⊂the␈α∂most␈α⊂efficient␈α∂way.␈α⊂ One␈α⊂evening␈α∂I␈α⊂trapped␈α∂along␈α⊂about␈α∂200␈α⊂meters␈α⊂of␈α∂the
␈↓ α∧␈↓Zigzag␈αWest␈αof␈αa␈αcertain␈αbridge␈αwith␈α
sunken␈αbucket␈αtraps␈αand␈αcaught␈αtwo␈αshrews.␈α A␈α
few␈αnights
␈↓ α∧␈↓later␈α
I␈α
trapped␈α
along␈αthe␈α
200␈α
meters␈α
East␈αof␈α
the␈α
bridge␈α
with␈αordinary␈α
box␈α
traps␈α
and␈αcaught␈α
twelve
␈↓ α∧␈↓Deer␈α
Mice␈α
(␈↓↓Peromyscus␈α
maniculatus␈↓),␈α∞four␈α
California␈α
Redback␈α
Voles␈α∞(␈↓↓Clethrionomys␈α
occidentalis␈↓),
␈↓ α∧␈↓and␈αone␈αTownsend's␈αChipmunk␈α(␈↓↓Eutamias␈αtownsendii␈↓).␈α
 I␈αprobably␈αwould␈αhave␈αcaught␈αmore␈α
if␈αI
␈↓ α∧␈↓had␈αchecked␈αthe␈αtraps␈αmore␈α
often␈αand␈αreset␈αthem.␈α I␈αcaught␈α
not␈αone␈αsingle␈αshrew.␈α The␈αnext␈α
night
␈↓ α∧␈↓I␈α∂trapped␈α∂again␈α∂on␈α∞the␈α∂200␈α∂meter␈α∂area␈α∞East␈α∂of␈α∂the␈α∂bridge,␈α∞using␈α∂the␈α∂sunken␈α∂bucket␈α∞technique
␈↓ α∧␈↓again,␈α∂and␈α∂caught␈α∂one␈α∂shrew.␈α∂ (Who␈α∂knows␈α∞what␈α∂creatures␈α∂both␈α∂methods␈α∂miss?)␈α∂It␈α∂was␈α∂a␈α∞very
␈↓ α∧␈↓graphic demonstration of the selectivity of the trapping techniques.

␈↓ α∧␈↓␈↓ αTI␈α
trapped␈α
in␈α
a␈α
very␈α
small␈α
are␈α
and␈α
caught␈α
both␈α
Water␈α
Shrews␈α
and␈α
Trowbridge␈α
Shrews.␈α
 Two
␈↓ α∧␈↓workers␈α∂from␈α∂Lewis␈α∂and␈α⊂Clark␈α∂College,␈α∂Jean␈α∂Robertson␈α∂and␈α⊂Dan␈α∂Barret,␈α∂trapped␈α∂a␈α⊂few␈α∂miles
␈↓ α∧␈↓lower␈α∞down␈α
and␈α∞caught␈α
only␈α∞Trowbridge␈α∞Shrews,␈α
though␈α∞this␈α
may␈α∞have␈α
been␈α∞because␈α∞they␈α
did
␈↓ α∧␈↓not␈α
trap␈α
very␈αnear␈α
the␈α
edge␈αof␈α
the␈α
river.␈α
 Nearer␈αto␈α
Portland,␈α
the␈αonly␈α
shrews␈α
are␈αTrowbridge␈α
and
␈↓ α∧␈↓Wandering.

␈↓ α∧␈↓␈↓ αTShrews␈αare␈α
notoriously␈αhard␈α
to␈αkeep␈α
in␈αcaptivity.␈α I␈α
was␈αtold␈α
that␈αTrowbridge␈α
Shrews␈αhad
␈↓ α∧␈↓never␈αbeen␈αkept␈αalive,␈αand␈αindeed,␈αsearching␈αthe␈αliterature,␈αI␈αwa␈αonly␈αable␈αto␈αfind␈αone␈αaccount␈αof
␈↓ α∧␈↓them␈α∪in␈α∩captivity.␈α∪ Yet␈α∩I␈α∪believe␈α∩the␈α∪difficulties␈α∩of␈α∪keeping␈α∩shrews␈α∪alive␈α∩have␈α∪been␈α∩greatly
␈↓ α∧␈↓exaggerated.␈α
 (And␈α
then,␈α
they␈α∞don't␈α
live␈α
very␈α
long␈α∞under␈α
any␈α
conditions,␈α
considering␈α∞their␈α
short
␈↓ α∧␈↓lifespan).␈α∂ One␈α⊂thing␈α∂that␈α∂may␈α⊂contribute␈α∂greatly,␈α∂however,␈α⊂to␈α∂the␈α∂mortality␈α⊂of␈α∂captives,␈α⊂is␈α∂the
␈↓ α∧␈↓moisture␈αlevel.␈α The␈αthree␈αspecies␈αof␈αshrews␈αthat␈α
I␈αkept␈αall␈αcame␈αfrom␈αmoist␈αhabitats.␈α Getz␈α
(1965),
␈↓ α∧␈↓studying␈αthe␈αdistribution␈αof␈α␈↓↓Blarina␈αbrevicauda␈↓␈αand␈α␈↓↓Sorex␈αcinereus␈↓,␈αfound␈αthat␈αthe␈αmost␈αimportant
␈↓ α∧␈↓factor␈α⊂governing␈α⊂their␈α⊂distribution␈α⊃was␈α⊂the␈α⊂necessity␈α⊂for␈α⊂a␈α⊃habitat␈α⊂with␈α⊂close␈α⊂to␈α⊃one␈α⊂hundred
␈↓ α∧␈↓percent␈α
humidity.␈α
 A␈αnumber␈α
of␈α
researchers␈α
reported␈αthat␈α
they␈α
kept␈αtheir␈α
shrews␈α
humid,␈α
or␈αthat
␈↓ α∧␈↓shrews␈αwithout␈αdrinking␈αwater␈αwould␈αdie,␈αbut␈αI␈αdon't␈αthink␈αthe␈αimportance␈αof␈αmoisture␈α
has␈αbeen
␈↓ α∧␈↓sufficiently␈α
emphasized.␈α (For␈α
some␈αspecies␈α
-␈αthose␈α
that␈αlive␈α
in␈αdry␈α
or␈αdesert␈α
areas␈α-␈α
this␈αshould␈α
be
␈↓ α∧␈↓unimportant).␈α
 Shrews␈α∞posess␈α
a␈α∞powerful,␈α
obnoxious␈α∞and␈α
penetrating␈α
odor␈α∞at␈α
all␈α∞times,␈α
and␈α∞it␈α
is
␈↓ α∧␈↓one's␈α
natural␈α
instinct␈αto␈α
house␈α
them␈αin␈α
a␈α
clean␈αdry␈α
cage␈α
lined␈αwith␈α
dry␈α
absorbent␈α
material,␈αsince
␈↓ α∧␈↓moisture␈αseems␈αto␈αmake␈αthem␈αsmell␈αeven␈αworse.␈α My␈αshrew␈αC,␈αwhich␈αlived␈αthe␈αlongest,␈αand␈αwhich
␈↓ α∧␈↓eventually␈αdied␈αof␈αold␈αage,␈αwas,␈αdue␈αto␈αa␈αshortage␈αof␈αscreen,␈αhoused␈αin␈αa␈αtank␈αwith␈αa␈αclose␈αfitting
␈↓ α∧␈↓glass␈αtop,␈αwhich␈αwas␈αconsequently␈αvery␈αmoist.␈α It␈αwas␈αnot␈αuntil␈αfairly␈αlate␈αin␈αthe␈αyear␈αthat␈αI␈αmade
␈↓ α∧␈↓the␈αconnection␈α
between␈αmoisture␈α
and␈αlongevity.␈α
 I␈αthen␈αprovided␈α
my␈αshrews␈α
with␈αwet␈α
leaves␈αand
␈↓ α∧␈↓glass-topped␈α∞tanks,␈α∞or␈α∞alternated␈α∞glass␈α∞and␈α∞screen␈α∞tops␈α∞-␈α∞I␈α∞had␈α∞no␈α∞more␈α∞deaths.␈α∞ Shrews␈α∞which
␈↓ α∧␈↓died␈α∞earlier␈α
in␈α∞the␈α
year␈α∞either␈α∞died␈α
of␈α∞obvious␈α
old␈α∞age,␈α∞or␈α
of␈α∞unknown␈α
causes.␈α∞ A␈α∞shrew␈α
whose


␈↓ α∧␈↓␈↓ ε|3␈↓ ∧



␈↓ α∧␈↓death␈αwas␈αmysterious␈α
usually␈αfirst␈αlost␈α
weight␈αsteadily,␈αand␈α
then␈αdied␈αin␈α
convulsions.␈α I␈αcame␈α
upon
␈↓ α∧␈↓one␈αas␈αit␈α
was␈αdying␈αdue␈α
to␈αold␈αage,␈αand␈α
it␈αtoo␈αwas␈α
convulsing,␈αwith␈αparalysis␈α
of␈αthe␈αhind␈αlimbs.␈α
 It
␈↓ α∧␈↓is␈α
possible␈α
that␈α
as␈αthey␈α
weaken,␈α
they␈α
succumb␈α
to␈αsome␈α
endemic␈α
disease␈α
which␈α
they␈αcould␈α
ordinarily
␈↓ α∧␈↓resist␈α-␈αperhaps␈αrabies.␈α It␈αis␈αeasy␈αto␈αtell␈αwhen␈αa␈αshrew␈αis␈αold.␈α For␈αone␈αthing,␈αits␈αfur␈αbecomes␈αdull
␈↓ α∧␈↓and␈α∩tacky␈α∪-␈α∩but␈α∩that␈α∪might␈α∩be␈α∩the␈α∪result␈α∩of␈α∩sickness.␈α∪ But␈α∩also,␈α∩at␈α∪that␈α∩time,␈α∩its␈α∪teeth␈α∩are
␈↓ α∧␈↓exceedingly␈α
worn.␈α
 This␈αis␈α
usual␈α
with␈α
shrews␈αin␈α
captivity␈α
or␈α
in␈αthe␈α
wild,␈α
(Rudd␈α
1955).␈α Their␈α
teeth
␈↓ α∧␈↓do␈α∞not␈α∞continue␈α
to␈α∞grow␈α∞as␈α
do␈α∞those␈α∞of␈α∞rodents.␈α
 My␈α∞captive␈α∞shrews␈α
showed␈α∞clear␈α∞signs␈α∞of␈α
this.
␈↓ α∧␈↓They␈αcould␈αno␈αlonger␈αcrunch␈αup␈αtheir␈αmealworms␈α
in␈αfew␈αbites,␈αbut␈αwere␈αforced␈αto␈αsqueeze␈αout␈α
the
␈↓ α∧␈↓soft␈αinsides.␈α Their␈αconsumption␈αof␈αthe␈αsoft␈αcatfood␈αwent␈αup␈αas␈αthe␈αmealworms␈αbecame␈αtoo␈αmuch
␈↓ α∧␈↓to handle, and then they would sicken and die.  After death their teeth were found to be worn.

␈↓ α∧␈↓␈↓ αTThe␈α
Water␈α
Shrew,␈α
one␈α
of␈αthe␈α
species␈α
I␈α
kept,␈α
is␈αa␈α
lovely␈α
and␈α
fascinating␈α
creature.␈α
 (Fig.␈α8a
␈↓ α∧␈↓and␈α∞b).␈α∞ The␈α
local␈α∞subspecies,␈α∞the␈α
only␈α∞one␈α∞in␈α
the␈α∞Western␈α∞U.S.,␈α
is␈α∞called␈α∞the␈α
␈↓↓navigator␈↓.␈α∞ It␈α∞is␈α
a
␈↓ α∧␈↓good␈αswimmer␈αand␈αcatches␈αmuch␈αof␈αits␈αfood␈αin␈αswift␈αmountain␈αstreams.␈α To␈αaid␈αit␈αin␈αswimming␈αit
␈↓ α∧␈↓has␈α∞fringes␈α∂of␈α∞stiff␈α∞short␈α∂hairs␈α∞along␈α∞the␈α∂edges␈α∞of␈α∞tis␈α∂feet.␈α∞ Mammal␈α∞books␈α∂state␈α∞that␈α∂these␈α∞are
␈↓ α∧␈↓found␈αon␈αthe␈αhind␈αfeet␈α
only,␈αand␈αthat␈αin␈α␈↓↓navigator␈↓␈αthey␈α
are␈αblack.␈α (Ingles␈α1965;␈αBurt␈α1964).␈α
 This
␈↓ α∧␈↓is␈αtrue,␈αbut␈αon␈αall␈αthe␈αwater␈αshrews␈αI␈αhave␈αseen,␈αthere␈αwere␈αalso␈αjust␈αas␈αprominent␈αfringes␈αon␈αthe
␈↓ α∧␈↓front␈α
feet,␈αwhite␈α
in␈α
color.␈α (See␈α
Fig.␈α8b).␈α
 What␈α
the␈αdifference␈α
is␈αI␈α
do␈α
not␈αknow.␈α
 Either␈αno-one␈α
has
␈↓ α∧␈↓noticed␈α
that␈α
␈↓↓S.P.␈α
Navigator␈↓␈αhas␈α
fringes␈α
on␈α
the␈α
front␈αfeet␈α
as␈α
well␈α
as␈αon␈α
the␈α
back␈α
feet␈α
where␈αthe
␈↓ α∧␈↓books␈αsay␈αthey␈αare,␈αor␈αthis␈αis␈αa␈αpeculiarity␈αof␈αa␈αlocal␈αpopulation.␈α The␈αway␈αto␈αcheck␈αthis␈αwould␈αbe
␈↓ α∧␈↓to examine museum collections.

␈↓ α∧␈↓␈↓ αTShrews␈α
are␈α
fascinating␈α
creatures␈α
with␈α
many␈α
remarkable␈α
aspects.␈α
 As␈α
a␈α
result␈α
some␈α
of␈αtheir
␈↓ α∧␈↓attributes␈α
have␈αpassed␈α
into␈αmyth,␈α
even␈αamong␈α
scientists␈α
who␈αought␈α
to␈αknow␈α
better.␈α It␈α
is␈αoften␈α
said
␈↓ α∧␈↓that␈α
a␈α
shrew␈α
must␈α
daily␈α
eat␈α
an␈α
amount␈α
of␈α∞food␈α
equal␈α
to␈α
its␈α
own␈α
weight␈α
in␈α
order␈α
to␈α∞survive.␈α
 A
␈↓ α∧␈↓small␈α
shrew␈α
can␈αeat␈α
its␈α
weight␈αor␈α
more␈α
daily,␈αbut␈α
it␈α
is␈αprobably␈α
untrue␈α
for␈αall␈α
but␈α
the␈αvery␈α
smallest
␈↓ α∧␈↓species␈α
that␈α
it␈α
must␈α
do␈α
so.␈α
 A␈α
Masked␈α
Shrew␈α
(␈↓↓Sorex␈α
cinereus␈↓),␈α
in␈α
captivity,␈α
weighed␈α
over␈α
the␈α
period
␈↓ α∧␈↓of␈αa␈αweek␈αan␈αaverage␈αof␈α3.6␈αgrams␈αand␈α
ate␈αan␈αaverage␈αof␈α11.7␈αgrams␈αof␈αfood␈αper␈α
day.␈α (Blossom
␈↓ α∧␈↓1932).␈α∂ Walker␈α∞(1964)␈α∂reports␈α∂a␈α∞captive␈α∂Gray␈α∞Shrew␈α∂(␈↓↓Notiosorex␈α∂crawfordii␈↓)␈α∞of␈α∂around␈α∂5␈α∞grams
␈↓ α∧␈↓which␈αate␈αdaily␈αfood␈αequal␈α
to␈αabout␈αthree-fourths␈αits␈αweight,␈α
but␈αalso␈αwent␈αfor␈αtwo␈α
days␈αwithout
␈↓ α∧␈↓eating␈α
at␈αall,␈α
and␈αsuffered␈α
no␈αill␈α
effects.␈α
 A␈αWater␈α
Shrew␈αthat␈α
I␈αkept,␈α
which␈αwas␈α
in␈α
good␈αhealth,
␈↓ α∧␈↓weighed␈α
over␈α
the␈α
week␈α
of␈α
Feb.␈α
9-16␈α
an␈α
average␈αof␈α
13.8␈α
grams␈α
and␈α
ate␈α
an␈α
average␈α
of␈α
6.2␈αgrams
␈↓ α∧␈↓daily.  This amount occasionally was much less or much more, but usually did not vary.
















␈↓ α∧␈↓␈↓ ε|4␈↓ ∧