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| Ecology and Behavior |
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Habit:Oceanic
Most sightings of pygmy sperm whales are of small groups of less than five or six individuals. Almost nothing is known of the behavior and ecology of this species, other than what has been learned from brief sightings during research cruises. They are generally not commonly seen alive at sea, but they are among the most frequently stranded small whales in some areas. When seen at sea, they have usually appeared slow and sluggish, and often float at the surface with no visible blow. Very little is known of the reproductive biology of the pygmy sperm whale. |
| Feeding and Prey |
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Diet dominated by:Cephalopods
Studies of feeding habits, based on stomach contents of stranded animals, suggest that this species feeds in deep water on cephalopods and, less often, on deep-sea fishes and shrimps.
Feeding mode:Seizing
Known prey species:
Cephalopods:Heteroteuthis dispar, Lycoteuthis lorigera, Abralia sp., Octopoteuthis sp., Moroteuthis sp., Histioteuthis sp., Illex argentinus, Ornithoteuthis antillarum, Chiroteuthis veranyi, Onychoteuthis banksi, Chiroteuthis sp., Lepidoteuthis grimaldii, Histioteuthis hoylei, Cycloteuthis sirventi, Gonatus steenstrupi, Taonius pavo, Histioteuthis meleagroteuthis, Histioteuthis corona corona |
| Threats and Status |
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Main threats:
Harvest
Fisheries bycatch
Plastic pollution
Conservation status:
The pygmy sperm whale is not listed as threatened or endangered by either the IUCN or the U.S. government. Although they have never been taken in large numbers, either directly or incidentally in fisheries, pygmy sperm whales have been occasional victims of dolphin and small whale fisheries, as well as gillnet and purse seine operations. Other potential threats include plastic ingestion (as associated gut-blockage) and ship strikes.
The National Marine Fisheries Service considers animals in U.S. waters to be members of several distinct stocks, and assesses them separately. Delineations between stocks are often difficult to determine, therefore assessments should be considered ongoing processes. In the case of the pygmy sperm whale, concern that sightings may be confused with the cogener K. sima (the dwarf sperm whale) further complicates the estimation of abundance. Stocks are estimated as follows
California/Oregon/Washington stock 4,746 (CV=0.67) 1991, 1993, and 1996 surveys
All Kogia sp. (K. breviceps and K. sima) in the northern Gulf of Mexico 547 (CV=0.28) 1991-1994 shipboard surveys
All Kogia sp. in the western North Atlantic stock 536 (CV=0.45) 1998 shipboard and aerial surveys
For current information on the conservation status of this species, please consult the following websites.
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| References |
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Baird, R.W., D. Nelson, J. Lien, and D.W. Nagorsen. 1996. Status of the pygmy sperm whale, Kogia breviceps, in Canada. Canadian Field-Naturalist 110:525-532.
Caldwell, D.K., and M.C. Caldwell. 1989. Pygmy sperm whale Kogia breviceps (de Blainville, 1838) Dwarf sperm whale Kogia simus Owen, 1866. Pp. 234-260 in S.H. Ridgway and R. Harrison, eds. Handbook of marine mammals, Vol. 4 River dolphins and the larger toothed whales. Academic Press.
Dos Santos, R.A. and M. Haimovici. 2001. Cephalopods in the diet of marine mammals stranded or incidentally caught along southeastern and southern Brazil (21-34° S). Fisheries Research 5299-112.
McAlpine, D.F. 2002. Pygmy and dwarf sperm whales Kogia breviceps and K. simus. Pp. 1007-1009 in W.F. Perrin, B. Würsig and J.G.M. Thewissen, eds. Encyclopedia of marine mammals. Academic Press.
McAlpine, D.F., L.D. Murison, and E.P. Hoberg. New records for the pygmy sperm whale, Kogia breviceps (Physeteridae) from Atlantic Canada with notes on diet and parasites. Marine Mammal Science 13701-704.
Ross, G.J.B. 1979. Records of pygmy and dwarf sperm whales, genus Kogia, from southern Africa, with biological notes and some comparisons. Annals of the Cape Provincial Museums (Natural History) 15:259-327.
Scott, M.D., A.A. Hohn, A.J. Westgate, J.R. Nicolas, B.R. Whitaker, and W.B. Campbell. 2001. A note on the release and tracking of a rehabilitated pygmy sperm whale (Kogia breviceps). Journal of Cetacean Research and Management 3:87-94.
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