就像冬天來(lái)了人們總想跑到熱帶的溫泉（SPA）以擺脫寒冷一樣，棲息在南極海岸附近的殺人鯨（又稱逆戟鯨）有時(shí)候也會(huì)離開冰冷的家鄉(xiāng)海域而小憩片刻,。
對(duì)這種生活在地球最南端的6米長(zhǎng)的鯨目動(dòng)物進(jìn)行的首個(gè)人造衛(wèi)星標(biāo)記顯示,，全部5頭進(jìn)行了標(biāo)注的殺人鯨都會(huì)在3周多的時(shí)間里，離開通常屬于它們的2攝氏度的海域,，向東前往位于烏拉圭和巴西海域的20攝氏度的?？颂m群島。其中一頭殺人鯨在42天的時(shí)間里游完了長(zhǎng)達(dá)9400公里的往返行程,。
這些殺人鯨在前往北方目的地的過(guò)程中會(huì)以更慢的速度游水,，然而它們?cè)卺鳙C或照顧幼鯨的時(shí)候卻從未真正降低過(guò)游水的速度，這意味著這些遠(yuǎn)行并非像典型的鯨類遷徙那樣是為了覓食或繁殖,。
事實(shí)上,，研究人員日前在《生物學(xué)快報(bào)》網(wǎng)絡(luò)版上指出，殺人鯨前往更溫暖的海域是為了恢復(fù)它們的皮膚——這些事情是鯨類在寒冷的水中所無(wú)法完成的，因?yàn)檫@一過(guò)程會(huì)將熱血從它們的身體內(nèi)部消耗掉,。
海豹通過(guò)爬上陸地脫皮來(lái)解決這一問(wèn)題,，然而由于缺乏這樣的本領(lǐng)，殺人鯨或許真的需要展開一次SPA之旅,。
逆戟鯨是一種大型食肉動(dòng)物,，體重9噸左右，背呈黑色,，腹為灰白色,，牙齒鋒利，性情兇猛,，善于進(jìn)攻獵物,，是企鵝、海豹等動(dòng)物的天敵,。有時(shí)它們還會(huì)襲擊其他鯨類,，甚至是大白鯊，可稱得上是海上霸王,。（生物谷 Bioon.com）
doi:10.1098/rsbl.2011.0875
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Antarctic killer whales make rapid, round-trip movements to subtropical waters: evidence for physiological maintenance migrations?
J. W. Durban and R. L. Pitman
Killer whales (Orcinus orca) are important predators in high latitudes, where their ecological impact is mediated through their movements. We used satellite telemetry to provide the first evidence of migration for killer whales, characterized by fast (more than 12 km h−1, 6.5 knots) and direct movements away from Antarctic waters by six of 12 type B killer whales tagged when foraging near the Antarctic Peninsula, including all tags transmitting for more than three weeks. Tags on five of these whales revealed consistent movements to subtropical waters (30–37° S) off Uruguay and Brazil, in surface water temperatures ranging from −1.9°C to 24.2°C; one 109 day track documented a non-stop round trip of almost 9400 km (5075 nmi) in just 42 days. Although whales travelled slower in the warmest waters, there was no obvious interruption in swim speed or direction to indicate calving or prolonged feeding. Furthermore, these movements were aseasonal, initiating over 80 days between February and April; one whale returned to within 40 km of the tagging site at the onset of the austral winter in June. We suggest that these movements may represent periodic maintenance migrations, with warmer waters allowing skin regeneration without the high cost of heat loss: a physiological constraint that may also affect other whales.
