Research Note 

Fishing Arctic Foxes AZopex Zagopus on a rocky island 
in West Greenland 
SUSSIE MQLLER NIELSEN 

Nielsen. S. M. 1991: Fishing Arctic Foxes Alopex lugopur on a rocky island in West Greenland. Polar 
Research 9(2). 211-213. 

On a small barren island in Disko Bay, West Greenland, 195 hours were spent observing Arctic Foxes at 
their den and the nearby coast. Their main food was found to be live, caught fish, and the activity of the 
foxes was correlated with the tidal height. 

S. M .  Nielsen, Arctic Station, Uniuersity of Copenhagen. DK-3953 Godhaun. Greenland. 

Introduction 
Although previously published works contain brief and des- 
ultory remarks indicating that the Arctic Fox Alopex lagopus 
is capable of catching live fish (Cranz 1765; Fabricius 1780; 
Sarmundsson 1939; Pedersen 1959). only Kaikusalo (1971) de- 
scribes actually having seen a fox unsuccessfully trying to catch 
a fish. Hence, no detailed description of fishing Arctic Foxes 
has been given to date. 

This paper aims to describe how Arctic Foxes catch live fish, 
how efficient they are, and to what extent they can iely on this 
food source. 

Study area 
The study took place on a 2 kmz island (0-70 m a.s.1.) that 
belongs to the archipelagos of Kronprinsens Ejland. Disko 
Bay (69N 53 W). West Greenland. The island is formed by 
Precambrian rocks, and except for two small beaches the coast- 
line (9 km) is rocky (1/3 steep cliffs). The distance to the nearest 
island is 1.8 km. At low tide several rock pools with rich seaweed 
vegetation (mainly Fucur disticur) are uncovered. The tidal 
fluctuation varied during June and July from 0.1 m to 2.7 m 
(mean 0.8 m). The island is sparsely vegetated by dwarf shrub 
heath, mainly Crowberry Empetrum hermaphroditum. Herb 
and marsh vegetation is found in narrow zones around ponds. 
Terrestrial animal life is poor (see also Porsild & Ostermanna 
1921). N o  signs of other mammals were found, and the only 
breeding bird species observed was the Snow Bunting Plec- 
trophennr niualis. Along the coast, however, several species of 
sea birds were foraging and some were seen resting on the cliffs 
almost daily. 

Materials and methods 
The observations were initiated 22 June 1990 when a family of 
dark phased (“blue”) foxes was located. A t  the timGof discovery 

the family consisted of 2 adults (nursing female and male) and 
6 cubs (4-5 weeks old). The two adults were easily identified 
by distinct fur characteristics. and sex-determination of the male 
was made at close hand. The family was still intact on 30 July 
when the last observations were made. Within this period the 
island was visited for ten 2 4 h o u r  periods. In total. 195 hours 
were spent observing both the den and about 200 m coastline 
with rock pools. The observations were made from cliffs at 
about l O m a . s . l . . 7 0 m f r o m t h e d e n , a n d  100mfromthecoast. 
The equipment consisted of binoculars (10 x 50) and a watch. 
The time (to the nearest minute) was recorded when an adult 
fox began to forage between the coastal rocks and the moment 
it stopped or went out of sight. Also recorded were the moment 
when a fish was caught and when an item was delivered to the 
cubs. Fish and other items were identified when possible. I n  
addition, sleeping sequences were noted: the time when an 
adult went to sleep as well as the length of time it slept were 
recorded. The results are related to tide tables for Kronprinsens 
Eiland 1990. 

Results 
At least one adult fox was in focus for 39 hours and 14 minutes 
(20% of the observation time). The adults were in sight simul- 
taneously for 39 minutes, so the total observation time of 
individual adult foxes was 39 hours and 53 minutes (the male 
was observed for 24 hours and 7 minutes, the female for 15 
hours and 32 minutes, and there were 14 minutes when the sex 
could not be recognized). Altogether the two adults foraged at 
the coast for 6 hours and 59 minutes (range 1-37 minutes) 
distributed over 32 sequences. Within this time a minimum of 
25 fish were caught (mean 17 minutes per catch and 0.8 fish per 
sequence). The male caught 9 fish in 4 hours and 13 minutes 
(13 sequences; mean 28 minutes per catch and 0.7 fish per 
sequence). The female caught 16 fish in 2 hours and 46 minutes 
(19 sequences; mean 10 minutes per catch and 0.8 fish per 
sequence). One morning when conditions for fishing may have 
been especially favourable. the female caught 6 fish in 28 
minutes. 



212 Siissie M d l e r  Nielsen 

70 

A 

--- 

I - m  

6 

r; 

r 

2 
Tidal height 

Fig. I .  The proportion ( % )  of the ohservation time thc adult 
l o w \  spent foraging it1 t h c  cciast ( A )  and slccping ( B )  in relation 
t u  t h e  tidal height Observation timc in minutes: 314(1 (U.(k 
( 1 . 5 m ) , 4 0 j 5 ( ~ l  5-1 llm);2270(1.(k1.5rn);XZS~l.i-2 0 i n ) a n d  
300 (2.lL-2 5 m) 

T h s  ioxci were <c'cn searching for food at the coast only when 
the tide was helow I m. and the amount of timc spent foraging 
was inver\cly proportional to the tidal height (Fig. I A ) .  O n  the 
contrary. 8 4 5  of thc time \pent slccping ( a l w a l s  in the cliffs 
ahovc the d e n )  occurrcd Hhen the tidc wai ahovc 1 m (Fig 
1B). Thc adult foxc, were o b w r \ c d  sleeping for a total of I4 
hour< and 4 minutes ( t h c  malc was observed slccping for a total 
of 8 hour< and 5 5  ininutes and the female for 5 hours and 
9 minute\). Thc mean slccping timc wa\ 34 minutes (range 
J-105. n = 2 5 ) .  

When the foxes travelled along the coast they foraged eithcr 
h\ turning scdwecd u i t h  a front paw and gleaning Amphipode< 
from the algae. or b) searching for fish in cracks and rock pools 
on thcir way 

Whcn fishing. thc fox would stand with its hindquarters on 
the edge of a pool. the tail pointing vertically upwards. and 
with mo\t of i t s  head and forepart hidden hetween rocks and 
seawccd. During thc catch, the fox twisted its tail from side to 

FIR. 7 Adult f o x  catching live fish in a rock pool (field sketch). 

sidc to kccp its balance. These fishing scenarios lasted only for 
a few seconds. after which the fox often appeared with a wrig- 
Fling fish in its mouth (Fig. 2). T h e  fox either delivered thc fish 
(often still wriggling) to the cubs, ate it on the way hack to the 
den. o r  left i t  on a rock while continuing to fish. Fivc times a 
fox was seen depositing a fish between rock5 o r  in ii m a l l  holc 
( I 0  to 15 cm deep) in the nearest surroundings o f  the d e n .  These 
h o b  were dug with the front paws. and after depositing t h e  
prey the fox covered the holca by pushing and patting the earth 
down with its nose. Thc foxc5 were not sccn entering the water 
t n  catch tkh: they were usually wet only on the head and 
torcpart when they returned from fishing. They often spent 
ronir timc drying thcir coats by ruhhing thcinsclvcs against t h e  
vegetation On one occasion thc male returned t o  the den 
waking wet. with a Lump-sucker Cyclopfmcs /uwipits. indi- 
cating that it might have hccn necessary for him to cntcr the 
water to catch the large f s h .  After delivering the fish to the 
cubs. he shook the water off his coat and ruhbcd against the 
vcgctation. Only once was a fox seen swimming hctwcen the 
\kerrics of the c o a s  ( a  distance of about 2 m). hut I have seen 
Arctic Foxes swim across a 10 ni wide river o n  several occasions 
i n  anothcr location. They are steady hut not fast swimmers. 
I)ing fairly high in the water (head and back dry and the tail 
floating behind). partly held up by the dense and puffy coat. 
Immcdiately after swimming. the fox shakes the water from the 
coat. often while it is still moving o n .  

Of 40 items delivered to the cuhs ( 2 3  fish. I Snow Bunting. 
1 wing of il Raven Curous corux and 15 not identified). most 
were delivered at low tide ( i l  rn) and most items delivered at 
high tide had been dug up from prey dcposirs near the den 
(Table I ) .  

I n  all. 36 fish were seen caught, delivered to the cuhs, or 
both: I Y  Banded Gunnels Pholis fnvciurw, 2 Lump-suckers, 1 
Father-lasher Myoxocephulus sp. and 13 not determined. 



Fishing Arctic Foxes Alopex lagopus on n rocky island in West Greenland 213 

Tuhle I .  Total observation time at low tide (< 1 m) and high tide (> 1 m), the number and frequency of items delivered to the 
cubs and of items dug u p  and delivered. 

Obs. time i n  
minutes (%) 

Items delivcred 

No. No./hour 

Items dug u p  and 
delivered (9; of 
items delivered) 

Tidal height: 
< I m  
> l m  
Total 

7195 (61) 

11700 (100) 
4505 (39) 

32 
8 

40 

0.3- 
0.1- 
0.2- 

Discussion 
The present observations document that Arctic Foxes are able 
to catch live fish with a high degree of success. They were not 
seen. however, alluring the fish with a paw as described by 
Cranz (1765) and Fabricius (1780). 

That hunting took place mainly at low tide and that live. 
caught fish comprised the most important food source for the 
fox family during the observation period are supported by the 
following facts: 1 )  Prey delivered to the cubs consisted primarily 
of fish; 2 )  Prey were delivered mainly at low tide; 3) Most prey 
delivered at high tide were dug up from deposits; 4) The bulk 
of the sleeping time occurred during high tide. 

A number of wings of sea birds found at the den had probably 
been taken from a nearby hut where several leftovcrs from 
hunters lay scattered. including wings of sea birds of the same 
species as found at the den (the hut was not in use during the 
study period). 

Arctic Foxes inhabit several small islands in the Disko Bay, 
and fishing foxcs may be a common. hut overlooked, phenom- 
enon. In Iceland remains of Lump-sucker is commonly found 
at fox dens (Hersteinsson 1984). 

The present island is much smaller than Arctic Fox home 
ranges measured by radiotracking elsewhere (marc than 8 km?) 
(Eherhardt et al. 1982; Hersteinsson & Macdonald 1982: Birks 
& Penford 1990). A rocky coastline may therefore be a richer 
habitat for Arctic Foxes than both inland and heach areas due 
to the foxcs’ ahility to catch live fish with high efficiency. This 
may be an important new aspect in the understanding of the 
distribution and ecology of the Arctic Fox. 

Acknowledgements. - For company and assistance in the field 
I want to thank T. B. Berg, A .  Caulfield and 0. Frimer. Special 
thanks go to A .  Jensen for her efforts and participation in the 
field. I am also grateful to P. Provencal for translating parts of 
Factno Groenlundicu (Fabricius 1780) from Latin to Danish. and 
to H .  Walhovd and L .  Albright for various help. 

The manuscript benefitted from criticism and suggestions from 
0. Frimcr and P. Mdgaard and was kindly read by E .  Muus. 
The study is supported by grants from the Commission for 
Scientific Research in Greenland and thc Carlsberg Foundation. 

References 
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of arctic foxes Alopex lugopus in Eqalummiut Nunaat. West 
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Cranz, D. 1765: Hisrorie oon Grdnlund. Leipzig. 
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A. & Hanson. E. E. 1982: Arctic Fox home range charac- 
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Fdbricius, 0. 1780: Fuicrtu Groerf/undicu. Hafnia & Lipsiac. 
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