By Nancy Shefferly
Geographic Range
The dwarf sperm whale is most often sighted in coastal waters.
Biogeographic Regions:
indian ocean (native 
); atlantic ocean (native ); pacific ocean (native ).
Habitat
Although dwarf sperm whales spend most of their time at the surface of the water near the shore, they forage at great depths.
Physical Description
(299.2 to 598.4 lbs; avg. 448.8 lbs)
The dwarf sperm whale has a porpoise-like form, with the blowhole positioned on the left side of the forehead, and a shark-like mouth posterior to the snout. The skull is asymetrical. The greatest girth of the body is between the dorsal and pectoral fins. The skin is a steel- gray color with a white ventrum. Some individuals have pink or purplish blotches on their venters. The head and body measure 210-270cm. The pectoral fin is 40 cm high, and the expanse of the flukes is 61 cm. The head is 1/6 of the entire length of the animal. The facial part of the skull is the shortest of any cetacean. The large teeth are sharp and curved, and they are present in the lower jaw only. Small non-functional teeth may be present in the upper jaw.
Some key physical features:
endothermic ; bilateral symmetry .
Reproduction
Liitle is known about the reproductive cycle of this rare whale. Males and females become sexually mature at lengths of 2.1 to 2.2 meters. Gestation is approximately nine months, and there appears to be a calving season that lasts four to five months. Females are typically seen in association with only one calf, indicating that single births are the norm. Calves are approximately 1 meter long at birth. Interestingly, the body proportions of these animals do not change as the calves mature.
Key reproductive features:
gonochoric/gonochoristic/dioecious (sexes separate); sexual ; viviparous .
Behavior
Dwarf sperm whales are reported to be sluggish creatures, often seen floating around on the surface of the water close to shore. They are typically social. Groups of ten or fewer animals are normal. Sexually mature males and females are found in the same groups, and there is some evidence that immatures form their own groups. Intraspecific fighting has been reported, but the nature of these conflicts is not known.
Key behaviors:
natatorial ; motile ; social .
Food Habits
The dwarf sperm whale feeds at great depths. The shape and position of the mouth indicate that this whale may feed very near the ocean floor. The diet of this species consists mainly of cephalopods, fish and crustaceans found at depths of 250-1300 meters.
Primary Diet:
carnivore (molluscivore ).
Animal Foods:
fish; mollusks; aquatic crustaceans.
Economic Importance for Humans: Positive
This whale is too rare to have any real economic importance to humans. However, researchers have suggested that the rarity of these sluggish animals may be due overharvesting of populations in the past.
Conservation Status
Cites Appendix II.
Contributors
Nancy Shefferly (author), Animal Diversity Web Staff.
