Acta Theriologica, 22, 29, 1977
389
Daily Food Consumption of Captive Moles
D ob ow e zużycie pokarm u przez krety w n iew oli
O lu w adare F U N M IL A Y O 1
F unm ilayo O., 1977: D aily fo o d consum ption o f cap tive m oles. A cta
theriol., 22, 29: 389— 392 [W ith 1 Table].
T h e quantity o f earth w orm s consum ed daily by 4 captive m oles was
m easured fo r 10 w eeks. T h e gut contents o f large earth w orm s w ere
rem ov ed b e fo r e they w ere fed to m oles and all m oles w ere fe d at the
sam e period o f the day and ad libitum . T h e lightest m ole consum ed
a sign ifican tly sm aller am ount o f food than each o f the h eavier ones
w h ile each fem a le consum ed sign ifican tly m ore food per unit o f body
w eigh t than m ales.
[Dept. A gric. Zool., S ch ool o f A gricu ltu re, W est M ains Road, E dinburgh
EH9 3JF, G reat Britain].
I. IN TR O D U C TIO N
Few previous w orkers have m easured the food consum ption of captive
moles. S k o c z e ń (1957) found that captive males fed on meat consum ­
ed 50°/o o f their body w eight while captive fem ales fed on earthworm s
consum ed 100% o f their body w eight daily. H a w k i n s & J e w e l l
(1962) found that a captive m ole consumes betw een 33.3% to 5 0% of
its b od y w eight daily w hen fed on earthworms. M e l l a n b y (1967) esti­
mated the daily food intake to be 5 0 % of the body w eight when a
captive m ole was fed only on demand.
The only record of the quantity of food consumed by w ild moles in
their natural habitat is that of G o d f r e y & C r o w c r o f t (1960). They
found the m axim um w eight of food in a fu ll stomach to be 16 g and
that w ild m oles have three daily periods of activity. They then estimated
that if a m ole fills its stomach six times daily, at the beginning and end
o f each active period, the m axim um w eight of food consum ed w ill be
96 g w hich is rou ghly equivalent to the body w eight of an adult mole.
The discrepancies in previous estimates suggest a need for further
critical study of food consum ption in this species. The present study
m easured food consum ption in fou r captive moles.
II. M A T E R IA L S A N D M ETH O DS
T he design o f the cages w as adapted from those o f S k o c z e ń (1961) and
R u d g e (1906). M oles w ere housed in d ividu ally in w ooden cases com prising o f a
sleeping com pa rtm en t and a feedin g com partm ent lin ked together by tw o tunnels
each one m eter lon g by 5 cm in diam eter. The cages w ere kept in an unheated
o u t-h ou se and clean ed regularly.
Seven m oles w ere kept in captivity b etw een 30th July 1968 and 9th July 1969
o f w hich on ly 4 su rviv ed fo r up to 10 w eeks. The gut contents o f large earthw orm s
1 Present address: Dept. A gric. Biol., Univ. Ibadan, Ibadan, Nigeria.
Acta T'heriologica, 22, 20, 1977
390
w ere rem ov ed b e fo r e they w ere fed to m oles w hile the heads o f sm aller earthw orm s
w ere crushed to m inim ise the chances o f their escape from the feedin g com pa rt­
ment. Each m ole w as p rovid ed w ith 100 g o f earth w orm s tw ice daily at 9.00 a.7ti.
and 6.00 p.m. so that the quantity o f fresh earthw orm s available w as alw ays in
excess o f w hat a m ole could eat. T h e w eight o f earth w orm s consum ed by each
m ole w as record ed daily fo r ten w eeks.
III. RE SU LTS
The daily consum ption of earthworm s was relatively high in the first
w eek in all m oles and also in the second w eek in m ole Nos. 2, 3 and 4
(Table 1). Data fo r this period was therefore excluded in further
T ab le 1
D aily earth w orm consum ption in gram s (M ean ± S.E.) o f captive m oles during
10 w eeks.
W eeks
1
2
3
4
5
6
7
8
9
10
3— 10
In per
cent o f
B ody wt.
No. 1
A du lt M ale
107.7 g
No. 2
J u ven ile Fem ale
76.5 g
No. 3
A du lt Fem ale
81.0 g
91.0±4.3
77.2±4.5
76.2±1.8
82.0+2.2
82.9+1.8
79.3+4.7
80.0+1.9
81.0+2.7
76.0+1.9
75.1 + 1.7
79.1 + 1.2
84.6+2.2
74.0+2.4
62.4+1.1
60.0+1.0
65.1 + 1.6
67.0+1.4
65.0+1.5
65.0+1.5
62.3+1.8
65.3+1.4
64.0+1.5
85.6+2.2
85.3+4.2
65.4+5.3
74.6+4.7
75.9+3.9
72.3+3.7
68.1+7.5
167.0+0.6
73.4+2.0
77.0+2.1
71.7+1.5
89.3+3.2
82.9+4.3
66.9+2.9
67.3+3.2
67.6+2.7
67.0+2.7
68.1 + 1.5
71.0+2.4
76.4+2.5
76.1+2.5
70.1+1.00
73.5+0.9
83.4+1.0
88.6+1.9
73.6+1.5
No. 4
A du lt M ale
95.0 g
calculations. On the other hand, daily earthworm consum ption was rela­
tively less variable in subsequent weeks w hich suggests that each m d e
should be allow ed to adapt to artificial confinem ent for tw o weeks before
m easurem ent of fo o d consum ption com m ences (cf. also H a w k i n s &
J e w e l l , 1962).
M ole No. 1 was heavier (Table 1) and ate significantly (P > 0.05) more
earthworm s than each of the other m oles w hile m ole No. 2 was lighter
and ate significantly less than each of the others. M ole Nos. 3 and 4
ate approxim ately equal quantities of earthworm s (Table 1).
The tw o fem ales each consum ed significantly (P > 0.05) m ore food
per unit o f their body w eight than the tw o males but food consumption
per unit o f body weight was equal in both males and in both females
indicating that the differences in food consum ption per unit of body
w eight was related to sex rather than the differences in body weig.it
(Table 1).
Acta Theriologica, 22, 29, 1977
391
IV. D ISC U SSIO N
The estimates o f fo o d consum ption obtained in the present study
agree w ith those obtained b y S k o c z e n (1957) and G o d f r e y &
C r o w c r o f t (1960). The results of M e l l a n b y (1967) could not be
com pared w ith the present estimate because he measured basically the
minimum food intake of a mole.
H i s a w (1923) has shown that in Scalopus aquaticus m achrinoides the
daily food intake is norm ally 32.1°/o of the body weight but a hungry
m ole m ay consum e up to 66.6°/o of its body weight daily. This suggests
that captive m oles whose food consum ption is to be com pared should
be fed at the same period of the day to ensure that they are under
similar gastronom ic conditions. Also, food consum ption should be com ­
pared only in m oles fed on the same diet because according to H a w k i n s
& J e w e l l (1962) the calorific value of the diet may influence food
consum ption in moles. It is further suggested that the gut contents
should be rem oved from large earthworm s fed to moles whose food
intake is being measured. This is because the gut of a large earthworm
like Lum bricus terrestris, Lum bricus jestivu s and Octalasium cyaneum
contains soil particules and food debris w hich m ay account for up to
1 0% of its fresh weight. M oles squeeze out and reject the gut contents
of large earthw orm s but sw allow small and m edium -sized earthworms
w hole w ith the gut contents. Therefore, if a m ole is fed exclusively on
large earthw orm s from w hich the gut contents w ere not rem oved its
food consum ption m ay be exaggerated by about 10%.
The present results indicate that heavy m oles m ay consum e m ore food
than light ones, a tendency w hich has been observed in field data (L a rk i n, 1948; G o d f r e y & C r o w c r o f t , 1960; S k o c z e n , 1966; F u n m i 1 a y o, 1970). Also, the present results supply new evidence to the
extent that captive fem ales consum e significantly (P > 0.05) m ore food
per unit of b ody w eight than males, because earlier results from field
data (F u n m i 1 a y o, 1970) indicated that food consum ption per unit of
body w eight was equal in the sexes except in M ay when lactating females
consum e m ore fo o d per unit of body w eight than males. The discrepancy
between laboratory and field results m ay arise from the fact that captive
moles w ith unlim ited food supplies ate to their full capacities while
m any w ild m oles w ere trapped when their stomachs were em pty or
only partially filled.
Confinem ent in solitary cages m ay alter the feeding behaviour and
food consum ption o f a norm ally sociable and free-ranging animal.
S o u t h w i c k (1955) in fact found that food consum ption in mice
decreases as population size increases. H owever, moles are solitary
( G o d f r e y & C r o w c r o f t , 1960) so that confinem ent in individual
cages largely simulates the social conditions obtaining among wild moles
and should therefore not affect their food intake except in the first one
or two weeks in confinem ent when the m oles were adjusting to human
presence and handling.
In conclusion, it w ill appear that most of the factors affecting food
consum ption in a m ole have been taken into account in the collection and
392
Acta Tberiodogica, 22, 29, 1977
interpretation of the present data w hich could therefore be regarded as
a reliable estimate of food consum ption in this species.
Acknowledgements: This report is part o f a Ph.D. thesis subm itted to the U ni­
versity o f Edinburgh. I w ish to thank Dr. W . J. G u i l d fo r supervising the w ork
and P rofessor K enneth M e l l a n b y fo r v alu able a d vice and keen interest in the
w ork.
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