PYGMY SPERM WHALE
Kogia breviceps (Blainville 1838)

Order Cetacea : Family Kogiidae

DESCRIPTION. A small, toothed whale; upperparts, top of pectoral fins, and flukes blackish; underparts and upper lip white; dorsal fin small, situated posteriorly to the midpoint on back, the tip pointing backward; pectoral fin short and spear shaped; blowhole an oblique crescent left of midline; mouth small and subterminal; snout blunt; skull short, broad, spongy, and markedly asymmetrical; left naris large, right one degenerate, as in the sperm whale; front part of skull deeply bowl shaped. Teeth small, slender, and widely spaced, 12–16 in each lower jaw. Total length 2–4 m. Measurements of one whale: total length, 3.2 m; snout to anterior edge of dorsal fin, 1.7 m; height of dorsal fin, 76 mm; length of pectoral fin, 495 mm. Weight of adults, >300 kg.

DISTRIBUTION. These whales are found in warm waters worldwide. In the western North Atlantic they occur from Nova Scotia to Cuba and as far westward as the Texas coast, where strandings occur relatively frequently. They were once thought to be quite rare, but stranding records indicate they may be more common than originally believed. The most recent stranding period (2002–2014) included 18 strandings of these small whales from nine different counties along the Texas coast.

SUBSPECIES. Monotypic species.

HABITS. This is a deepwater, pelagic species about which very little is known. They occur in small groups of three to six individuals and appear slow and deliberate in their actions. Low frequency, low intensity, pulsed sounds have been recorded from these whales, suggesting that they may be capable of echolocation.

Their food habits are not well known. Stomachs that have been examined contained carapaces and appendages of green crabs, shrimp, and beaks of squid.

Information available suggests that mating takes place in late summer, and the young are born the following spring after a gestation period of some 9 months. The young calf stays with its mother during its first year, as judged from records of capture of pregnant females accompanied by offspring of the previous year. Newborns are about 1.2 m long and weigh 54 kg. Strandings of these whales may often be related to calving, as females with newborn young often strand, as do females whose reproductive tract shows evidence of parturition just prior to stranding.

POPULATION STATUS. Uncommon; strandings and observations. Although pygmy sperm whales frequently strand on the coastline of the Gulf of Mexico, including Texas, these small whales overall are relatively uncommon in the Gulf fauna and their habits prevent them from being readily observed. Estimate of abundance from shipboard and aerial sightings in all seasons was about 1,000 individuals in the northern Gulf.

CONSERVATION STATUS. Although it is not listed by the USFWS, the pygmy sperm whale is listed as threatened by the TPWD. The IUCN lists it as "data deficient" because there is considerable uncertainty about its abundance and population trends.

 

From The Mammals of Texas, Seventh Edition by David J. Schmidly and Robert D. Bradley, copyright © 1994, 2004, 2016.  Courtesy of the University of Texas Press.