ACTA THERIOLOGICA
Vol. 23, 23: 371—380, 1978
Minimum and Maximum Metabolic Rates
of Sorex sinuosus
James R. NEWMAN & Robert L. RUDD
N e w m a n J . R. & R u d d R. L., 1978: M i n i m u m a n d m a x i m u m m e t a b o l i c
r a t e s of Sorex sinuosus.
Acta theriol., 23, 23: 371—380 [With 1 Fig. &
5 Tables].
T h e m i n i m a l a n d m a x i m a l m e t a b o l i c r a t e s of Sorex
sinuosus
are
similar to o t h e r species of s h r e w s . T h e s e m e t a b o l i c r a t e s s h o w e d consid e r a b l e v a r i a b i l i t y d e p e n d i n g u p o n t h e season, n u t r i t i o n a l state, sex
b e h a v i o r a n d t i m e of day. T h e a v e r a g e m i n i m a l m e t a b o l i c r a t e at 20 c C
is 4.5 'kcal/day w h i l e t h e a v e r a g e m a x i m u m m e t a b o l i c r a t e at 20°C is
6.0 k c a l / d a y . Only u n d e r e x t r e m e f a s t i n g c o n d i t i o n s did m i n i m a l m e t a bolic r a t e s a p p r o a c h p r e d i c t e d b a s a l v a l u e s f o r s m a l l m a m m a l s . T h e
c o n s t a n t l y a c t i v e n a t u r e of s h r e w s c o n t r i b u t e s to t h e h i g h metabolic
r a t e s o b s e r v e d in S.
sinuosus.
[Environ. Sci. Engineer., Inc. P.O. B o x 13454, Univ. Stat., Gainesville,
F l o r i d a 32605 (JRN) a n d Dept. Zool., U n i v . Calif., Davis, C a l i f o r n i a 95616
(RLR)].
I. I N T R O D U C T I O N
Opinion is divided as to why the observed »basal« metabolic ratets of
shrews are higher than the predicted basal metabolic rates derived from
K 1 e i b e r's {1967) allometric equation for mammals of similar size. One
group of investigators believes that these observed high metabolic rates
are characteristic of shrews ( P e a r s o n , 1948; G < ? b c z y r i s k i , 1965,
1971a; G ^ b c z y n s k a & G ^ b c z y n s k i , 1965; P o c z o p k o , 1971;
V o g e l , 1976). V o g e l <1976) compared the metabolism of 13 species of
shrews and concluded that only the tribe Soricini have a uniquely higher
metabolic rate. The subfamily Crocidurinae is characterized by relatively
low metabolic rates. The tribes Neomyini and Blarinini have intermediate
metabolic rates. Other investigators attribute these observed high values
to experimental conditions such as SDA and activity ( M o r r i s o n , et al.,
1959; H a w k i n s et al., 1960; B u c k n e r , 1964; M a r t i n s e n , 1969;
P i a t t , 1974).
Several factors are known to significantly affect the metabolism of
small mammals including size, shape, sex, reproductive condition, ciradian variation, season, activity and temperature (G e s s a m a n , 1973;
G r o d z i n s k i & W u n d e r , 1975). Detailed studies on the metabolism
and factors affecting the metabolism of the genus of Sorex have been
[371]
372
J. R. Newman & R. L. Rudd
conducted on five species: S. araneus ( G ^ b c z y n s k i , 1965); S. arcticus;
S. cinereus ( B u c k n e r , 1964); S. minutus ( G ^ b c z y n s k i , 1971b). Additional studies on other species are needed to further explain the metabolic uniqueness of shrews ( P o c z o p k o , 1971). The objectives of this
study were to measure the minimum and maximum metabolic rates of
S. sinuosus and to determine some factors influencing the metabolic
rate of this species.
II. M A T E R I A L A N D M E T H O D S
Sorex sinuosus is a s m a l l i n s e c t i v o r e w h i c h occurs in t h e n o r t h e r n salt m a r s h e s
of S a n P a b l o Bay a n d S u i s u n Bay, of C a l i f o r n i a ( R u d d , 1955). At b i r t h S.
sinuosus
w e i g h s a b o u t 0.5 g r a m s a n d g r o w s to a n a v e r a g e w e i g h t of 4.5 g r a m s . R e p r o d u c u v e i y a c t i v e s h r e w s m a y w e i g h as m u c h as 7 g r a m s ( R u d d , 1955). Reproduct i v e a c t i v i t y s t a r t s in l a t e F e b r u a r y , r e a c h e s a p e a k in May, a n d declines s h a r p l y in
e a r l y J u n e ( J o h n s t o n & R u d d , 1957). S. sinuosus h a s a life e x p e c t a n c y of less
t h a n one y e a r a l t h o u g h a s m a l l n u m b e r of i n d i v i d u a l s do s u r v i v e t h r o u g h t h e
second y e a r . T h e r e is a t u r n o v e r in age classes of a d u l t s b o r n t h e p r e v i o u s y e a r to
a d u l t s b o r n in t h e c a l e n d a r y e a r d u r i n g t h e s u m m e r . A t this t i m e t h r e e a g e classes
c a n be i d e n t i f i e d : juveniles, y o u n g a d u l t s , a n d old a d u l t s ( R u d d 1955). B e c a u s e
of t h e d e f i n e d b r e e d i n g season a n d s e a s o n a l c h a n g e i n a g e classes, t h r e e seasons
w e r e recognized f o r a n a l y s i s : s p r i n g (March, April, May, a n d J u n e ) , l a t e s u m m e r
( J u l y , A u g u s t , S e p t e m b e r , a n d October), a n d w i n t e r ( N o v e m b e r , D e c e m b e r , J a n u a r y ,
a n d F e b r u a r y ) . S. sinuosus
w a s c a p t u r e d u s i n g S h e r m a n live t r a p s ( 2 2 X 8 X 8 cm)
d u r i n g 1967 to 1970. C a p t u r e d s h r e w s w e r e m a i n t a i n e d in t h e l a b o r a t o r y u n d e r t h e
n o r m a l l i g h t i n g r e g i m e of t h e salt m a r s h a n d f e d a m i x t u r e of beef b r a i n s a n d
P u r i n a C a t C h o w (Registered t r a d e m a r k ) . T h e a n i m a l r o o m a p p r o x i m a t e d t h e n o r m a l t e m p e r a t u r e r e g i m e of t h e salt m a r s h e s to w i t h i n 5°C.
O x y g e n c o n s u m p t i o n w a s m e a s u r e d in a m e t a b o l i s m c h a m b e r u s i n g a B e c k m a n
m o d e l F - 3 p a r a m a g n e t i c o x y g e n a n a l y z e r w i t h a s p a n of 19—21 p e r c e n t oxygen in
a n o p e n - c i r c u i t system. T h e millivolt o u t p u t of t h e a n a l y z e r w a s c o n t i n u o u s l y
m o n i t o r e d on a H o n e y w e l l S t r i p c h a r t r e c o r d e r . The» a n i m a l s w e r e s u p p l i e d w i t h
c a r b o n d i o x i d e - f r e e a i r a n d o x y g e n a n a l y s i s w a s also p e r f o r m e d on c a r b o n d i o x i d e f r e e air. O x y g e n c o n s u m p t i o n v a l u e s w e r e c a l c u l a t e d a c c o r d i n g to t h e f o r m u l a of
D e p o c a s & H a r t (1957) f o r o p e n - c i r c u i t systems. This p r o c e d u r e h a s b e e n f o u n d
to p r o d u c e a c c u r a t e r e s u l t s (H i 1 1, 1972).
T h e m e t a b o l i s m c h a m b e r w a s a 0.33 liter glass c h a m b e r . T h e f l o o r of t h e c h a m b e r
w a s w i r e d w i t h m i c r o - s w i t c h e s w h i c h detected a n y locomotor a c t i v i t y . T h i s activity
w a s r e c o r d e d s i m u l t a n e o u s l y w i t h o x y g e n c o n s u m p t i o n on a n E s t e r l i n e - A n g u s E v e n t
r e c o r d e r . By c o m p a r i n g o x y g e n c o n s u m p t i o n v a l u e s w i t h a c t i v i t y r e c o r d i n g s t h e
m e t a b o l i c r a t e s d u r i n g p e r i o d s of a c t i v i t y a n d i n a c t i v i t y could b e d e t e r m i n e d . D u r i n g
t h e e x p e r i m e n t s t h e m e t a b o l i s m c h a m b e r w a s s u b m e r g e d in a c o n s t a n t t e m p e r a t u r e
w a t e r b a t h k e p t at 20°C. Food a n d w a t e r w e r e p r o v i d e d ad libitum
d u r i n g each
e x p e r i m e n t . Metabolic m e a s u r e m e n t s w e r e m a d e w i t h i n t h r e e w e e k s of c a p t u r e .
T h e m i n i m a l m e t a b o l i s m w a s c a l c u l a t e d to be t h e m e a n of t h e l o w e s t oxygen
c o n s u m p t i o n v a l u e s o b s e r v e d in each 1 5 - m i n u t e i n t e r v a l t h r o u g h 24 h o u r s . M a x i m u m m e t a b o l i s m w a s t h e m e a n of t h e h i g h e s t v a l u e s o b s e r v e d i n each 15-minute
i n t e r v a l t h r o u g h 24 h o u r s .
Minimum and maximum metabolic rates of Sorex
sinuosus
373
III. R E S U L T S
The metabolic rate of S. sinuosus exhibited considerable variability
depending upon the season, nutritional state, behavior and time of day.
The minimal daily metabolic rate at 20°C ranged from 3.3 ±1.2 kcal/day
in the winter to 6.9 ± 1.2 kcal per day in the spring (Table 1).
Comparison of seasonal metabolic rates reveal a significant decline
[¿(.oij (44) = 3.214] in minimal daily metabolic rates from late summer to
winter. There is a significant increase [t(.oiK3i) = 3.645] in the metabolic
Table 1
C o m p a r i s o n of t h e seasonal m i n i m a l daily m e t a b o l i c r a t e a t 20°C of S.
with predicted basal metabolic rates.
Sex
No.
Wt.
(g)
Males
Females
Both
12
10
22
5.4+0.8
5.3+0.5
5.4+0.7
Males
Females
Both
15
9
24
5.0+0.8
4.8+0.6
5.0+0.7
Males
Females
Both
7
2
9
6.8+1.5
5.4
6.4+1.4
sinuosus
Observed minimal
P r e d i c t e d b basal Percent c
metabolic rate
metabolic rate
difference
(cc0 2 g— :l hr— l ) (kcal day— 1 ) a
(kcal day— 1 )
Late Summer
4.4+1.4
7.1+2.2
5.2+1.4
8.6+2.4
7.8+2.1
4.9+1.3
Winter
3.2+1.4
5.6+2.5
3.4+0.6
6.2+1.2
5.8+2.1
3.3+1.2
Spring
8.6+3.4
6.7+2.6
10.1
7.5
9.4+3.5
6.9+2.6
1.4
1.4
1.4
214
271
250
1.3
1.3
1.3
146
162
154
1.6
1.4
1.6
318
435
331
a kcal d a y - 1 = c c 0 2 g - 1 h r - 1 X 2 4 h r X w t ( g ) X 4 . 8 - M 0 0 0 . K l e i b e r (1961).
b k c a l / d a y = 69W.™+1.2 k c a l w h e r e W = k g . K l e i b e r (1961).
c (Minimal metabolic rate-predicted basal metabolic rate/predicted basal metabolic
rate)X100.
rates from winter to spring. No significant differences existed between
the seasonal body weights of these experimental animals. Fasting metabolic rates were observed in three shrews during experiments in which
food was deprived (Table 2). All experiments ended in the death of the
animal with measurement times lasting from 5 to 23 hours. Fasting
animals lost between 8 and 10°/o of their body weights. The minimal
metabolism observed three hours before death (considered post-absorptive) was significantly greater than the predicted basal values. These
values were 3 to 6 times greater than predicted basal values. At one
hour before death only one animal showed a metabolic rate significantly
higher than predicted basal values. At 15 minutes before death the
fasting metabolic rates of the three shrews were not significantly different from the predicted basal values.
374
il
t:
o)
•o« « I
^ cc/îd
ca
l
Oo
o
CL
«
-
o> > x:
« i •*->oS-i
»->
I I ? O -C
tH fljO
<v Un
P3
OJ
3
O
^«Ol
hNN
+1 +1+1
mMm
NN «
O) O -rP
<N w
+1+1 +1
CO ** co
eó c<i
( O ^ D3
CO O o
° o rt +I+I+)
O •""< .-H
CQ Q M to o
W
X!
(U
G
O
W
•
C)-G
.¡3
-<-'
ca
c/l <1)
«tj
4)
X3 T3 i)
t- t- co
«-Î o o
O o « +1
+1 +1
CO O 00
r-^ co tt
u <p &
m
ii 03^
-<II-> 2ca
W) U
G «M
o
^ o
•->
T3
v
L
<u 'a
u a)
0) -i->
-G «
0)
o CX
' É-.
121
-»-> ca CCO
a 2
<ca >3
ca _c
5 S 'C
Q
h
X
X'
c- io co
o o o
ca -G
X
w
h
ca
o.
SO
cj
G
cu
S £
T*< t~ t-^
t—' + cö
O) co --I
i i i
WHÜ
? G
co g
S «M
00
«M
oí
c\l
Il 'S M t- ^ ^
1 >»
S
•S c ® S s »
ú?
o °J5 oio S?
o
11
V M
ra M S3 u a o
Minimum and maximum metabolic rates of Sorex
sinuosus
375
Females had an average metabolic rate that was 15°/o higher than
males (Table 1). Although this difference was not significant, the higher
metabolic rates of females was observed in each season. Females showed
a greater variation in metabolic rate than males from season to season.
Comparison of the minimal metabolic rates of juveniles, young adults,
and old adults, showed that juveniles had the highest metabolism, and
old adults the lowest. However, this variation was not statistically significant and appears to be weight related (Table 3). One very old female,
Table 3
C o m p a r i s o n of t h e m i n i m a l m e t a b o l i c r a t e s of v a r i o u s a g e classes
of S. sinuosus in l a t e s u m m e r .
Juveniles
Number
Body w e i g h t (g)
M i n i m a l m e t a b o l i c r a t e (cc Oag—»hr—»)
Young Adults
7
3.7±0.3
9.5±5.7
Old A d u l t s
11
4.9+0.5
8.5+2.3
8
5.7+0.6
6.6+1.6
Table 4
C o m p a r i s o n of m e a n m i n i m a l a n d m a x i m u m m e t a b o l i c r a t e s f o r
l a t e s u m m e r , w i n t e r , a n d spring.
Late Summer
Number
22
M i n i m a l m e t a b o l i c r a t e (cc 02g—'hr—:l)
7.8±2.1 b
M a x i m u m m e t a b o l i c r a t e (cc 0 2 g — J h r — 9 . 5 ± 2 . 1 b
Percent a difference
22
Winter
Spring
24
5.8+2.1 c
8.8+2.1 c
52
9
9.4±3.5
12.4+3.3
32
a ( m a x . met. r a t e — m i n . met. r a t e / m i n . met. r a t e ) X100.
b S i g n i f i c a n t l y d i f f e r e n t ; t (.02) (42) =2.464.
c S i g n i f i c a n t l y d i f f e r e n t ; t (.ooi) <46) =4.784.
approximately 22 months old, had a metabolic rate similar to the rest
of the population sampled.
Activity was recorded in every hour during the metabolic experiments
and was a major factor in raising metabolic rate (Table 4). The maximum
daily metabolic rates corresponding to periods of activity were significantly higher (22 to 52°/o) than minimal daily metabolic rates. Although
maximum daily metabolic rates of spring were 32% higher than minimal
daily metabolic rates of the spring, they were not significantly different
[¿(.05)(i6)= 1.858]. Significant differences were observed between the diurnal and nocturnal metabolic rates of winter and spring individuals (Table
5). Individuals from the winter had a slightly greater diurnal metabolic
rate while individuals from the spring had a 24°/o greater nocturnal
metabolic rate. There was no significant difference between the diurnal
and nocturnal metabolism of late summer.
376
J. R. Newman & R. L. Rudd
IV. D I S C U S S I O N
Minimal metabolic rates of Sorex sinuosus are similar to the minimal
metabolic rates observed in other species of shrews, especially the genus
Sorex (Fig. 1). V o g e 1 (1976) derived an allometric equation for the minimal metabolism of Soricinae (M = 82.6W0-53, where M equals cal./hr. and
W equals grams). It best describes the late summer minimal metabolism
of S. sinuosus. The observed minimal metabolism of spring and winter
animals are respectively higher and lower than the metabolism described
Table 5
C o m p a r i s o n of t h e m e a n d i u r n a l m e t a b o l i c r a t e w i t h t h e m e a n n o c t u r n a l m e t a b o l i c
r a t e a n d n i g h t / d a y r a t i o s (N/D) f o r l a t e s u m m e r , w i n t e r a n d spring.
Winter
Spring
24
15
9.6+0.4
6.8+0.6 a
10.2+2.1 b
9.7+0.3
1.02
6.3+0.3 a
0.93
12.7+1.6 b
1.24
Late Summer
Number
Mean diurnal metabolic r a t e
(cc O z g - i h r - 1 )
Mean nocturnal metabolic rate
(cc 0 2 g ~ 1 h r —
N/D r a t i o
a
b
9
S i g n i f i c a n t l y d i f f e r e n t ; t (.05) (22) = 3 . 3 95.
S i g n i f i c a n t l y d i f f e r e n t ; t (.oi) (13) =3.070.
by this allometric relationship. At thermal neutrality, the minimal metabolic rates in other species of shrews are considerably higher than predicted basal values ( M o r r i s o n et al., 1959; H a w k i n s et ah, 1960;
G ^ b c z y r i s k a & G ^ b c z y r i s k i , 1965). Minimal metabolic rates
measured under post-absorptive conditions in S. sinuosus, Cryptotis parva (P f e i f f e r & G a s s, op. cit.), S. araneus, S. minutus, and Neomys
fodiens ( G ^ b c z y n s k i , 1971b) were found to be significantly higher
than predicted. Only under extreme fasting conditons resulting in death
of the animal did the observed metabolic rates of S. minutus and S. araneus significantly drop to near »basal« levels. This lowering of metabolism was associated with a reduction in activity of the fasting shrews
( G ^ b c z y r i s k i , 1971b). S. sinuosus showed the same response to extreme fasting. Seasonal variation in the metabolic rates of shrews is
common. Winter is a time of energy reduction in Neomys fodiens (G e bc z y n s k a & G ^ b c z y r i s k i , 1965), S. araneus and S. minutus (G e bc z y n s k i , 1965). A 34°/o decline in the metabolic rate from summer to
winter is observed in <S. sinuosus (Table 1).
In European shrews, a reduction in body size and organ weight also
occurs during the winter (D e h n e 1, 1949; P u c e k, 1965). An analysis
of the body weights of S. sinuosus revealed a similar seasonal drop in
Minimum and maximum metabolic rates of Sorex
sinuosus
377
body weights. The average body weight for S. sinuosus is 3.9 ±0.1 grams
(n = 43) in the winter compared to 4.3 ±0.1 grams (n = 50) for the summer
and 5.9 ±0.2 grams (n = 120) for the spring. This seasonal reduction in
metabolic rates and body weights of shrews is hypothesized as an adaptation for physiological conservation during periods of the year with high
energy demands ( G ^ b c z y r i s k i , 1965; M e z h z h e r i n , 1969).
20
r
. Neomys onomolus® GloucomySs*.
(?)
// -Neomys fodiens
volons
/ /
Microtus
. (es i iNapoeozapus ©pennsylvanicu
S pacificus® £ 4
mstqnis •
>
•
10
8
a>
Peromyscus truei
(S)
. ^ ® Clethri onomys
. Peromyscu^®
S. vaqrans^ ®S trowbndgii
®gapperi
" californicus
Microsorex hoyiT V - c arcxicus
Blanno#(S
nrctlfll ,©
_
brevicauda
W
S sinuosus®
'Peromyscus mamculatu
S cinereus Q
#S minutus®
I Peromyscus eremicus®
Peromyscus leucopus®
S cinereus
r
Mus musculus®
PREDICTED BASAL
METABOLISM, M A M M A L S
M = 0 3936 W075
I
I I I I I
8
10
20
J
40
I I I I II
60
80 100
BODY WEIGHT (grams)
Fig. 1. Comparison of the observed m i n i m a l metabolic r a t e s of s h r e w s with other
small m a m m a l s : 1 - M c N a b & Morrison, 1963; 2-Pearson, 1947; 3-Morrison et al., 1959;
4-GQbczynsiki, 1971a; 5-Buckner, 1964; 6 - P e a r s o n , 1948; 7-Gebczynska & G^bczyriski,
1965; 8 - M a r t i n s o n ; 1969; 9 - A u t h o r ; 10-G<?bczynski, 1965.
An increase in spring metabolic rates is observed in N. fodiens (G q bc z y n s k a & G ^ b c z y n s k i , 1965) and S. araneus ( G ^ b c z y n s k i ,
1965). S. sinuosus shows a 67% increase in metabolic rate from winter
to summer. These increases in energy expenditure of shrews are associated with increases in body size resulting in part from reproductive
maturation ( J o h n s t o n & R u d d , 1955; R u d d, 1955; P u c e k, 1965;
B r o w n , 1974) and increased activity associated with the reproduction
( B u c k n e r , 1969; C r o i n - M i c h i e l s e n , 1966; N e w m a n , 1976).
In the autumn metabolic rates of S. araneus and S. minutus are intermediate between the metabolic rates of spring and winter ( G < ? b c z y n s k i ,
1965; 1971). A similar pattern exists in S. sinuosus for late summer metabolic rates (Tab. 1).
378
J. R. Newman & R. L. Rudd
The metabolic sensitivity of shrews to activity can be seen in the
differences between the differences in maximum (active) and minimum
(resting) metabolic rates. Shrews are active twenty-four hours a day with
greatest amount of activity occurring at night ( H a m i l t o n , 1940;
C l o t h i e r , 1955; C r o w c r o f t , 1957; I n g l e s , 1960; S h i 11 i t o, 1963;
B u c h a l c z y k , 1972; N e w m a n , 1976). The difference in maximum
and minimum metabolic rates of shrews range from 28°/o in Blarina
brevicauda ( M o r r i s o n et al, 1959) to 343% in S. minutus (G b c z y ris k i, 1971a). In S. sinuosus the maximum metabolic rates were 20 to
52% higher than minimal metabolic rates (Table 4).
Activity was recorded every hour during the twenty-four hour experiments. Shrews averaged 8 to 12 periods of recorded locomotor activity
per hour. The duration of these activity periods ranged from a few
seconds to 10 minutes of sustained activity. Unrecorded activity such as
twitching and moving the nose was often observed during the »inactive«
periods. P i a t t (1974) and V o g e l (1976) conclude that the nearly constant activity of shrews makes the predicted basal values difficult to
obtain. The constant activity of S. sinuosus during the metabolic experiments supports their conclusions.
Nocturnal metabolic rates appear to be slightly higher than diurnal
metabolic rates and correlate with the higher amount of nocturnal activity observed in shrews. Night/day metabolic ratios range from 1.04 for
S. cinereus ( G r o d z i r i s k i , 1965) to 1.17 for S. minutus (G q b c z y ris k i, 1971a). S. sinuosus showed a similar pattern during the spring and
late summer with night/day ratios of 1.24 and 1.02, respectively. During
the winter, diurnal energy expenditure is slightly higher (Table 5). Seasonal variation in the night/day ratios is also observed in S. araneus
( G q b c z y r i s k i , 1965).
Investigations into the metabolic patterns of S. sinuosus and other
species of shrews reveal a number of significant factors affecting their
metabolic rates. Efforts at developing daily and annual energy budget
for shrews should account for these factors, especially seasonal and
behavioral influences.
A c k n o w l e d g e m e n t s : We w o u l d also like to t h a n k t h e l a t e . Dr M a x Kleiber,
U n i v e r s i t y of C a l i f o r n i a (Davis), f o r his g u i d a n c e d u r i n g t h e s t u d y . T h i s r e s e a r c h
w a s p a r t i a l l y s u p p o r t e d by C h a n c e l l o r ' s P a t e n t F u n d D. G. 132 a n d N S F G r a n t s
G. B. 6392 a n d G. B. 15916. I n addition, w e t h a n k W o r d P r o c e s s i n g C e n t e r , E n v i r o n m e n t a l Science a n d E n g i n e e r i n g , Inc. (Gainesville, Florida), f o r t y p i n g the
manuscript, and Joy Dabney, Western Washington University (Bellingham, Washington), f o r t h e a r t w o r k .
Minimum and maximum metabolic rates of Sorex
sinuosus
379
REFERENCES
1. B r o w n R. J., S e x u a l d i m o r p h i s m in t h e pelvic g i r d l e of t h e o r n a t e s h r e w ,
Sorex ornatus. W a s m a n n J. Biol. 32: 99—104.
2. B u c h a l c z y k A., 1972: S e a s o n a l v a r i a t i o n in t h e a c t i v i t y of s h r e w s . Acta
theriol., 17: 221—242.
3. B u c k n e r C. H., 1964: M e t a b o l i s m , food c a p a c i t y a n d f e e d i n g b e h a v i o r in f o u r
species of s h r e w s . C a n a d . J. Zool. 42: 259—279.
4. B u c k n e r C. H., 1969: S o m e a s p e c t s of t h e p o p u l a t i o n ecc'ogy of t h e c o m m o n
s h r e w , Sorex araneus n e a r O x f o r d , E n g l a n d . J . M a m m a l . 50: 326—332.
5. C l o t h i e r R. R., 1955: C o n t r i b u t i o n s to t h e life h i s t o r y of Sorex vagrans
in
M o n t a n a . J. M a m m a l . 36: 214—221.
6. C r o i n - M i c h i e l s o n N. C., 1966: I n t r a s p e c i f i c a n d i n t e r s p e c i f i c c o m p e t i t i o n
in t h e s h r e w s Sorex araneus L. a n d S. minutus
L. A r c h s n e e r l . Zool., 17: 73—
—174.
7. C r o w c r o f t P., 1957: T h e life of t h e s h r e w . R e i n h a r t : 1—166. L o n d o n .
8. D e h n e l A., 1949: S t u d i e s on t h e g e n u s Sorex L. A n n . Univ. M. C u r i e - S k l o d o w s k a , C. 4: 17—102.
9. D e p o c a s F. & H a r t J. S., 1957: U s e of t h e P a u l i n g O x y g e n A n a l y s e r f o r
m e a s u r e m e n t of o x y g e n c o n s u m p t i o n of a n i m a l s in o p e n - c i r c u i t s y s t e m s a n d
in a s h o r t - l a g , c l o s e d - c i r c u i t a p p a r a t u s . J. Appl. Physiol. 10: 338—392.
10. G ^ b c z y n s k a Z. & G ^ b c z y n s k i M., 1965: O x y g e n c o n s u m p t i o n in t w o
species of w a t e r s h r e w s . Acta theriol. 10: 209—214.
11. G ^ b c z y n s k i M., 1965: S e a s o n a l a n d a g e c h a n g e s in t h e m e t a b o l i s m a n d
a c t i v i t y of Sorex araneus L i n n a e u s , 1758. Acta theriol. 10: 303—331.
12. G ^ b c z y n s k i M., 1971a: T h e r a t e of m e t a b o l i s m of t h e lesser s h r e w . Acta
theriol. 16: 329—339.
13. G ^ b c z y n s k i M. 1971b: O x y g e n c o n s u m p t i o n in s t a r v i n g s h r e w s . A c t a theriol.
16: 288—292.
14. G e s s a m a n J. A. 1973: Ecological e n e r g e t i c s of h o m e o t h e r m s : A v i e w c o m p a t i b l e w i t h ecological modeling. U t a h S t a t e U n i v e r s i t y M o n o g r a p h s Series, 20:
1—155.
15. G r o d z i n s k i W., 1965: Bionergetics of s m a l l m a m m a l s f r o m A l a s k a n taiga
f o r e s t . L y n x , 6: 51—55.
16. H a m i l t o n W. J., J r . 1940: T h e biology of t h e s m o k y s h r e w ( S o r e x
fumeus
fumeus Miller). J . M a m m a l . 25: 473—492.
17. H a w k i n s A. E , J e w e l l P. A., & T o m l i n s o n G., 1960: T h e m e t a b o l i s m
of s o m e B r i t i s h s h r e w s . Proc. zool. Soc. Lond., 135: 99—103.
18. H i l l R. W. 1972. D e t e r m i n a t i o n of o x y g e n c o n s u m p t i o n by use of t h e p a r a m a g netic o x y g e n a n a l y s e r . J . Appl. Physiol. 33: 261—263.
19. I n g l e s L. G., 1960: A q u a n t i t a t i v e s t u d y of t h e a c t i v i t y of t h e d u s k y s h r e w
(Sorex vagrans obscurus). Ecology, 42: 655—660.
20. J o h n s t o n R. F. & R u d d R. L., 1957: B r e e d i n g of t h e salt m a r s h s h r e w .
J. M a m m a l . 38: 157—163.
21. K l e i b e r M. 1961. F i r e of life. J o h n Wiley & S o n s : 1—454. N e w Y o r k .
22. M a r t i n s e n D. L., 1969: E n e r g e t i c s a n d a c t i v i t y p a t t e r n s of s h o r t - t a i l e d
s h r e w s ( B l a r i n a ) on r e s t r i c t e d diets. Ecology, 50. 505—510.
23. M c N a b B. K. & M o r r i s o n P., 1963: Body t e m p e r a t u r e a n d m e t a b o l i s m in
subspecies of Peromyscus
f r o m a r i d a n d mesic e n v i r o n m e n t s . Ecology Mono.,
33: 63—82.
J. R. Newman & R. L. Rudd
380
24. M e 7. h z h e r i n V. A., 1969: E n e r g e t i c s of p o p u l a t i o n s a n d evolution of t h e
s h r e w s (Sorex, Insectivora,
Mammalia).
[In: K. P e t r u s e w i c z & L. R y s z k o w s k i
(Eds), « E n e r g y F l o w T h r o u g h S m a l l M a m m a l s Populations»]. P W N - P o l i s h S c i e n t i f i c P u b l i s h e r s : 149—156. W a r s z a w a .
25. M o r r i s o n P., R y s e r F. A. & D a w e A., 1959: S t u d i e s on t h e physiology of
t h e m a s k e d s h r e w , Sorex cinereus. Physiol. Zool. 32: 256—271.
26. N e w m a n J . R. 1976. P o p u l a t i o n d y n a m i c s of t h e W a n d e r i n g S h r e w
Sorex
vagrans. W a s m a n n J. Biol. 34: 235—250.
27. P e a r s o n O. P., 1947: T h e r a t e of m e t a b o l i s m of s o m e s m a l l m a m m a l s . Ecology, 28: 128—145.
28. P e a r s o n O. P., 1948: M e t a b o l i s m of s m a l l m a m m a l s w i t h r e m a r k s on t h e
l o w e r l i m i t of m a m m a l i a n size. Science 108: 44.
29. P f e i f f e r C. J . & G a s s G. H. 1962. O x y g e n c o n s u m p t i o n in t h e s m a l l s h o r t t a i l e d s h r e w ( C r y p t o t i s parva). T r a n s . 111. S t a t e Acad. Sci. 55: 130—132.
30. P i a t t W. J., 1974: M e t a b o l i c r a t e s of s h o r t - t a i l e d s h r e w s . Physiol. Zool. 47:
75—90.
31. P o c z o p k o P. 1971. Metabolic levels in a d u l t h o m e o t h e r m s . Acta theriol. 16:
1—21.
32. P u c e k Z. 1965. S e a s o n a l a n d a g e c h a n g e s in t h e w e i g h t of i n t e r n a l o r g a n s of
s h r e w s . A c t a theriol. 10: 369—498.
33. R u d d R. L. 1955. Age, sex, a n d w e i g h t c o m p a r i s o n s in t h r e e species of s h r e w s .
J. M a m m a l . 36: 323—339.
34. S h i 11 i t o J. F. 1963. Field o b s e r v a t i o n s on t h e g r o w t h , r e p r o d u c t i o n a n d
a c t i v i t y of a w o o d l a n d p o p u l a t i o n of t h e c o m m o n s h r e w Sorex araneus L. Proc.
Zool. Soc. Lond., 140: 94—144.
35. V o g e l P. 1976. E n e r g y c o n s u m p t i o n of E u r o p e a n a n d A f r i c a n s h r e w s . Acta
theriol. 21: 207—215.
Accepted,
January
4, 1978.
J a m e s R. N E W M A N & R o b e r t L. R U D D
TEMPO METABOLIZMU MINIMALNEGO I MAKSYMALNEGO
U SOREX
SINUOSUS
Z b a d a n o m i n i m a l n e i m a k s y m a l n e t e m p o m e t a b o l i z m u u Sorex sinuosus.
Obyd w a t e p a r a m e t r y c h a r a k t e r y z u j ą się dużą zmiennością i zależą od sezonu, płci,
w i e k u , o k r e s u doby i s t o p n i a n a j e d z e n i a . M i n i m a l n e , ś r e d n i e t e m p o m e t a b o l i z m u ,
m i e r z o n e p r z y 20°C w y n o s i 4.5 kcal/dobę, m a k s y m a l n e , m i e r z o n e w t e j s a m e j t e m p e r a t u r z e — 6.0 k c a l / d o b ę (Tabela 1). S a m i c e m a j ą ś r e d n i o o 15% wyższy m e t a bolizm niż samce. W zależności od sezonu t e m p o m e t a b o l i z m u u l e g a i s t o t n y m z m i a n o m : obniżeniu w o k r e s i e od k o ń c a lata do zimy i p o d w y ż s z e n i u od zimy do w i o sny (Tabela 4).Tylko głodzone r y j ó w k i , tuż przed ś m i e r c i ą g ł o d o w ą , w y k a z u j ą niższy
m e t a b o l i z m m i n i m a l n y niż o s z a c o w a n y dla nich m e t a b o l i z m p o d s t a w o w y (Tabela 2).
N a j w y ż s z y m t e m p e m m e t a b o l i z m u c h a r a k t e r y z u j ą się osobniki m ł o d e a n a j n i ż szym s t a r e (Tabela 3). Ustalono, że n a j w i ę k s z y w p ł y w n a t e m p o m e t a b o l i z m u w y w i e r a a k t y w n o ś ć r y j ó w e k (Tabela 4) — s t ą d m a k s y m a l n e d o b o w e t e m p o m e t a b o lizmu połączone z d u ż ą a k t y w n o ś c i ą r u c h o w ą jest do 55% w y ż s z e niż m i n i m a l n e .
O b s e r w o w a n o r ó w n i e ż i s t o t n e różnice w t e m p i e m e t a b o l i z m u dziennego i nocnego
u z w i e r z ą t w r ó ż n y c h sezonach (Tabela 5).