Dwarf and pygmy sperm whales in Hawai‘i

An adult dwarf sperm whale off the island of Hawai‘i. Photo by Daniel Webster. Note the blunt head and large dorsal fin.

Dwarf sperm whales (Kogia sima) and pygmy sperm whales (Kogia breviceps) are the only two members of the Family Kogiidae, and both species are found in Hawaiian waters. In our work we've encountered dwarf sperm whales 74 times beween 2002 and 2012, while we've seen pygmy sperm whales on only five occasions. However, pygmy sperm whales strand much more frequently than dwarf sperm whales in Hawai‘i.

It is often reported that the two species are difficult to tell apart in the field, but there are a number of characteristics that allow us to discriminate the two species. Click on the image above to download a PDF copy of the information sheet with details on how to distinguish between the two species.

A number of photographs of dwarf sperm whales and more information is below.

 

Dwarf sperm whale off Kona. Photo by Greg Schorr. Both species also have a reputation for being difficult to approach, although we have found that, while they are difficult to keep track of, this is due to their long dive times, undemonstrative surfacing behavior (most of the time they float motionless at the surface between dives), and their generally unpredictable travel patterns, rather than active avoidance of small boats.

Dwarf sperm whale mother and calf off Kona. Photo by Robin Baird. Most adult individuals that we see tend to be very well marked, with large notches on the dorsal fin or very distinctive dorsal fins. We have compiled a catalog of distinctive individual dwarf sperm whales off the island of Hawai‘i. As of February 2013 our catalog includes 42 distinctive individuals, 14 of which have been seen on more than one occasion. At the 2009 Biennial Marine Mammal Conference we presented a poster on this work - to download a copy click here The adult in the photo above, HIKs020 in our catalog, has been seen eight times in six different years, evidence of site fidelity.

Dwarf sperm whale off Kona. Photo by Dan McSweeney.

Group sizes of dwarf sperm whales are typically small, ranging from 1 to 8 individuals (our most frequently encountered group size are single individuals)

Another very distinctive dwarf sperm whale off Kona. Photo by Daniel Webster. We have also found that dwarf sperm whales, like their larger cousin the sperm whale, often shed skin even when just resting at the surface, and we have been able to collect several samples for genetic analyses just by looking in the "fluke prints" of whales after they dive.

Dwarf sperm whale with apparent line injury on dorsal fin. Photo by Annie Douglas.

A pygmy sperm whale off Kona, photo by Daniel Webster. We see pygmy sperm whales so infrequently we have not obtained many photos. This individual shows the very long back relative to the size of the dorsal fin, the rounded tip of the dorsal fin, and the hump in the back when logging at the surface, all characteristic of this species.

For more information on dwarf and pygmy sperm whales see the following publications:

  • Mahaffy, S.D., R.W. Baird, D.J. McSweeney, D.L. Webster, and G.S. Schorr. 2009. Individual photo-identification of dwarf sperm whales off the island of Hawai‘i; evidence of site fidelity and a small population size. Poster presented at the 18th Biennial Conference on the Biology of Marine Mammals, Quebec, October 2009. Download PDF copy

  • West, K.L., W.A. Walker, R.W. Baird, W. White, G. Levine, and E. Brown. 2009. Diet of pygmy sperm whales (Kogia breviceps) in the Hawaiian Archipelago. Marine Mammal Science 25:931-943. Download PDF copy The definitive version is available at Wiley InterScience

  • Baird, R.W. 2005. Sightings of dwarf (Kogia sima) and pygmy (K. breviceps) sperm whales from the main Hawaiian Islands. Pacific Science 59:461-466. Download PDF copy

  • Willis, P.M., and R.W. Baird. 1998. Status of the dwarf sperm whale (Kogia simus) in Canada. Canadian Field-Naturalist 112:114-125. Download PDF copy

  • Baird, R.W., D. Nelson, J. Lien and D.W. Nagorsen. 1996. The status of the pygmy sperm whale, Kogia breviceps, in Canada. Canadian Field-Naturalist 110:525-532. Download PDF copy

All photos are copyrighted and should not be used without permission.