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Research Note

Ringed seal hispida fright behaviour caused by Odobenus rosmarus

IAN GJERTZ

Gjertz, I. 1990: Ringed seal Phoca hisppida fright behaviour caused by walrus Odobenus rosmarus. Polar Research 8, 317-319. Other marine tend to avoid . The prcsent papcr describes two incidents of avoidance behaviour displagcd by ringed seals in the presence of a walrus. Ian Gjertz. Norsk Pularinstitutt, P.0. Box 158. N-1330 Oslo Lufthaun, Norway; February 1990 (revised April 1990).

Walruses (Odobenus rosmarus) are at the top of are shallow with many large rocks which are sub- the interspecific social hierarchy among northern merged during high tide. (Hediger 1955, in Fay 1960, 1981). At Andreetangen in 1987 I witnessed two inci- They are omnivorous and forage mainly on ben- dents of different ringed seals (Phoca hispida) thic prey, but it is well documented that some apparently frightened by the presence of a walrus. walruses eat other marine mammals (Fay 1960, On 31 July, while observing the haul-out beach 1981; Lowry & Fay 1984). It is a matter of dispute at 2255 hr and mid tide, I noticed a young walrus, whether walruses actively prey upon these, or which according to its small teeth, was an esti- merely are carrion feeders (Fay 1960, 1981). It mated 4 years old, swimming northwards along has only recently been verified in the scientific the shore of Andreetangen towards the haul-out literature that walruses actively catch and kill beach. At the same time a ringed seal (estimated mammalian prey (Timoshenko & Popov 1990). weight 40 kg) was approaching along the coast in Marine mammals are known to desert or avoid the opposite direction. When they were still about areas occupied by walruses (Collett 1911-12; 100 m apart, the ringed seal appeared to become Freuchen 1921; Pedersen 1930, 1951; Fay 1960), aware of the walrus because it stopped swimming but it is not known whether this is caused by a and lay still for a few seconds. It then swam predator-prey relationship or is due to inter- straight to a nearby rock and climbed, except for specific dominance (Pedersen 1951; Fay 1960, its hind flippers, out of the water. All the time it 1981). looked in the direction of the swimming walrus. Edgeoya, in Svalbard, is historically an area of It remained on the rock until the walrus had walrus occupation. Andreetangen (Fig. 1) is a passed, at a distance of 3@40m, and surfaced peninsula on southern Edgeoya, along which some 60 m farther up the coast. The ringed seal there are some islands. The narrow sound then carefully slid backwards and sideways into between Andreetangen and the closest island is the water and continued swimming southwards fairly shallow and has strong tidal currents. The out through the sound. The walrus swam up to benthic fauna in the sound is obviously abundant, the area in front of the haul-out beach and as can be deduced by the eiders (Somateria mol- remained in the shallow water there until 2320 hr issirnu), bearded seals (Erignathus barbatus), when it swam offshore and started diving, appar- belugas (Delphinapterus leucas) and walruses that ently feeding. This activity was continued until feed there. At the northern entrance to the sound 2350 hr. While this was going on, a second ringed on the Andreetangen side there is a beach used seal came swimming southwards along the coast by walruses to haul out. The waters off this beach heading for the sound. The seal was observed for 318 Ian Gjertz

eAndree-

Fig, I. Map of AndrCctangcn (Edgcflya). with [nap of Sval- hard encl(i\cd in iipprr left cor- ner.

about 10 minutes, swimming largely at the surface lundica) pup between its Hippers. When it saw making short regular dives. When it was about people, the walrus let go of the pup. which was 15C200m away from the walrus, its mode of still alive. The pup had a hole in its gut and a swimming suddenly changed, as its surfacing time large part of the intestines were hanging out. was rcduced to a minimum. The seal just shoved Timoshenko & Popov (1990) summarize several its nose above the water, made one or two short observations of walruses preying on seals in the breaths and submerged. The ringed seal surfaced . Seals obviously have reason to fear 4 times while in the area where the walrus was walruses. and surprisingly it only surfaced while the walrus Pedersen (1962) claims that the apparent fear was at the surface. They passed each other at a that ringed seals exhibit towards walruses indi- distance of approximately 6&70 m, the seal being cates that incidents of walruses preying on ringed closer to shore. When the seal was about 150 m seals are not infrequent. Pedersen (1934) writes past the walrus, it resumed its former mode of that walruses catch seals by swimming underneath swimming and was seen swimming into the sound. them and grabbing them with their foreflippers Though little evidence exists to show that when the seal surfaces to breathe. One of the walruses catch and kill live seals, there are indi- seals observed in this study did not surface while cations that this does occur. The well known the walrus was submerged and this may indicate sealer Waldemar Kraemer, in his unpublished that the seal feared the submerged walrus. The diary kept at the Norwegian Polar Research Insti- observations reported here may indicate that rin- tute library, claims to have seen this happen. ged seals fear walruses snd that they possibly Hantzsch (1977), from travels in Baffinland 1909- through active and/or passive acoustic means 1911, writes that his cskimos repeatedly had seen detect their presence, direction and when they walruses catch seals in the water, embrace them have surfaced. and kill them. Iversen (1927) mentions seeing a According to Pedersen (1934), walruses also walrus surfacing with a (Phoca groen- catch seals that are hauled out on ice. This is done Ringed seal fright behaviour caused by walrus 319 by suddenly surfacing in front of the seal and Collett. R. 1911-12: Norges Parfedyr. Asctichoug & Co. (W. grabbing it. This has been supported by Timo- Nygaard). Kristiania. 744 pp. shenko & Popov (1990). Phncid seals should be Fay. F. 11. 1960: Carnivorous walrus and some zoonom. Arcric IS. 1 11-122. able to outswim walruses (Perry 1967), something Fay. F. H. 1981: Walrus Odobenus rosmurus Linnaeus, 1758. that is also indicated by the swimming velocities Pp. 1-23 in Ridgcway. S. H. & Harrison, R. J. (eds.): Hurid- given for walruses (Fay 1981) and the largha seal book of marine mammcils I. Academic Press, London. 235 (Phoca lurgha) (Bigg 1981). If this is correct, it is PP. Frcuchen, P. 1921: Om hvalrosscns forckomst og vandringcr surprising that the seal first observed did not stay ved Grucnlands vcstkyst. Vidensk. Medd. Dansk riufurh. in the water, where it should be more able to Form. 72. 237-249. detect the whereabouts of the walrus, thus fac- 1Iantzach. B. 1977: My life amwig the EsskrmoA: Ba/Jinlund ilitating an escape. jourrieys in rhe years 1909-1911. Mawdsley Memoir Ill. 395 If the ringed seals could detect the presence of pp. (translated by L. H. Ncatby. University of Siiskatclicwan. Saskatoon). the walrus, then the opposite may probably also Hcdigcr, H. 195.5: Srrrdiev of rhe psyc/~o/o~.vund hehaoioirr of be true. However, I could not notice any change uriimals in zoos arid circuses. Butterworths. London. Ihh pp. in the behaviour of the walrus. Iverscn, T. 1927: Drivis og sclfangst. Aarsh. vedk. Norgev Fiskr. The two incidents observed at Edgeoya are too 1927 11). 1-84, few to give more than an indication of how ringed Lowry. L. F. & Fay, F. 1%.1984: Scal cating by walruscs in the Bcring and Chukchi Seas. Polar Riol. 3, 11-18. seals react to walruses. The apparent increase in Pederscn. A. 1Y30: Fortgesctztc hcitfigc zur kenntnis dcr the number of walruses in Svalbard in recent years Saugtier- und Vogelfauna der ostkuatc Griinlands. Medd. may provide ample opportunity to observe this in Grmnluncl 77. 341-507. the future. Pcdcrscn. A. 1934: Polurdyr. Gyldcndalske Boghandcl, Nor- disk Forlag, Copenhagen. 1.50 pp. Pedcrscn. A. 1951: Kosmarus. en heretiling om hc~olro.ssensliii og hrsrorie. Gyldendal, Copenhagen. 98 pp, Pcdcrscn. A. 1962: Dus Walro~s.A. Zicmscn Vcrlap. Wit- tcnhcrg Lutherstadt. 60 pp. References Pcrry. R. 1967: The world offhe wulrro. Cassell. London. 162 PP . Bigg. M. A. 1981: Harbour scal Phoc'ci iiirulirra Linnacus. 17.58 Timoshenko. Yu. K. & Popov, L. A. 1990: On predatory habits and /'/mu lrirgho Pallas. 1x1 1, Pp. 1-27 in Kidgcway S. H. of Atlantic walrus. The International Workshop on Populufioii & llarrison. R. J. (cdr.): Hondhook ofmurine mamnials 2. Ecology and Mauugemenf of Walruses. 2&30 Murcli 1990, Academic Press. London. 359 pp. Seafrle. Washmgton, USA.