A DWARF FORM OF KILLER WHALE IN ANTARCTICA

Publication Type:Journal Article
Year of Publication:2007
Authors:Pitman, RL, Perryman, WL, LeRoi, D, Eilers, E
Journal:Journal of Mammalogy
Volume:88
Pagination:43-48
Date Published:2007
ISBN Number:0022-2372
Keywords:Orcinus orca
Abstract:

In the early 1980s, 2 groups of Soviet scientists independently described 1, possibly 2 new dwarf species of killer whales (Orcinus) from Antarctica. We used aerial photogrammetry to determine total length (TL) of 221 individual Type C killer whales?a fish-eating ecotype that inhabits dense pack ice?in the southern Ross Sea in January 2005. We confirmed it as one of the smallest killer whales known: TL of adult females (with calves) averaged 5.2 m ± 0.23 SD (n = 33); adult males averaged 5.6 ± 0.32 m (n = 65), with the largest measuring 6.1 m. Female Type A killer whales?offshore mammal-eaters?from Soviet whaling data in the Southern Ocean were approximately 1?2 m longer, and males were 2?3 m (up to 50%) longer (maximum length 9.2 m). Killer whale communities from the North Atlantic and in waters around Japan also appear to support both a smaller, inshore, fish-eating form and a larger, offshore, mammal-eating form. We suggest that, at least in Antarctica, this degree of size dimorphism could result in reproductive isolation between sympatric ecotypes, which is consistent with hypotheses of multiple species of killer whales in the Southern Ocean.

URL:http://dx.doi.org/10.1644/06-MAMM-A-118R1.1
Taxonomic name: 
Thu, 2014-03-20 12:57 -- admin
https://secure.gravatar.com/avatar/5ade1b012674ce3dd941e2ea5dd15cc1.jpg?d=https%3A//mammals.indianbiodiversity.org/sites/all/modules/contrib/gravatar/avatar.png&s=100&r=G
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith