Part 13

Other Common Names

None known.

Description

Pygmy sperm whales reach a length of at least 11 feet (3.4 m). They are characterized by 1) an extremely robust body that rapidly tapers near the tail, 2) a squarish head, and 3) a narrow, underslung lower jaw which is located well behind the tip of the snout. Along the side of the head, in approximately the same position where gill slits would be located on a fish of comparable size, there is a crescent-shaped bracket mark, often called a false gill.

The flippers, which are smoothly curved on the forward margin and may reach a length of 18 inches (45.7 cm) or more on an adult specimen, are located well forward on the body, just below and behind the bracket mark.

The dorsal fin is very small, falcate, and located in the latter half of the back.

Though coloration can be described only from stranded specimens and a few encounters with living animals, pygmy sperm whales appear to be dark steel gray on the back, shading to a lighter gray on the sides, and gradually fading to a dull white on the belly. The outer surface of the flippers and the upper surface of the tail flukes are also steel gray.

Natural History Notes

From the few accounts, the following may be summarized about the behavior of pygmy sperm whales at sea: They reportedly usually rise slowly to the surface to breathe, produce a blow that is inconspicuous, and do not normally roll aggressively at the surface like most other species of small whales. They reportedly fold their flippers flat against their bodies when swimming. They have been reported to lie motionless in the water with the back of the head on the surface and the tail hanging loosely down in the water. (A similar behavior in sperm whales has made them a minor hazard to shipping, since it has resulted in some collisions with ships.) When they are startled in this posture, they may defecate, issuing a cloud of reddish brown to rust-colored fece. Beached pygmy sperm whales have also been observed to defecate a fine chocolate feces.

Pygmy sperm whales apparently feed primarily on squid, but do take fish as well.

May Be Confused With

In general, when they can be examined at close range, pygmy sperm whales are so distinctive that they are unlikely to be confused with any other species except perhaps the dwarf sperm whales. At a distance, they might be confused with small individuals of any of the beaked-whale species (p. 78) that also have a relatively small, falcate dorsal fin located in the latter third of the back. Closer examination should permit easy separation, however, since the pygmy sperm whale has a blunted head, while the beaked whales, as the name implies, have elongated "dolphinlike" beaks and are considerably larger. At sea, pygmy sperm whales are most likely to be confused with their cousins the dwarf sperm whales (p. 148 and Fig. 160). The two species can be distinguished as follows:

PYGMY SPERM WHALE DWARF SPERM WHALE

MAXIMUM SIZE

To 11 feet (3.4 m). To 9 feet (2.7 m).

DORSAL FIN

Small to 8 inches (20.3 cm), Taller, more like that of falcate; located in latter third bottlenosed dolphins; located of back. near the midpoint of the back.

COLORATION

Both species are dark steel gray on the back, grading to lighter on the belly.

Distribution

Because they have been rarely observed at sea, normal ranges for this species are not known. Based on stranding records, however, the following can be stated. In the western North Atlantic, pygmy sperm whales have been found as far north as Sable Island, Halifax, Nova Scotia, as far south as Cuba, and as far west as Texas in the Gulf of Mexico. They are frequently found stranded along the Atlantic coast of Florida and throughout the eastern and northern Gulf of Mexico.

Stranded Specimens

Because of the distinctive characters of the genus, stranded pygmy and dwarf sperm whales are unlikely to be confused with any other species of cetacean, though the rather narrow underslung jaw and the blunted head may result in their casual dismissal by some beach walkers as stranded sharks. The two species of Kogia may be distinguished by the following:

PYGMY SPERM WHALE DWARF SPERM WHALE

TEETH

12-16 (rarely 10-11) in lower 8-11 (rarely 13) small and jaw are larger; no teeth in extremely sharp teeth in upper. lower jaw; sometimes have up to 3 teeth in each upper jaw.

THROAT

No creases or grooves on Several short irregular creases throat. or grooves on throat.

DWARF SPERM WHALE (T)

_Kogia simus_ (Owen 1866)

Other Common Names

Rat porpoise (West Indies).

Description

Dwarf sperm whales reach an overall length of approximately 9 feet (2.7 m). Like the other species of _Kogia_, the pygmy sperm whale (p. 144), the dwarf sperm whales are characterized by 1) a squarish head, 2) an extremely robust body which tapers rapidly near the tail stock, 3) a narrow, underslung lower jaw, and 4) a bracket mark or false gill on the side of the head.

The dorsal fin of this species is tall and falcate, closely resembling that of the Atlantic bottlenosed dolphin, and is located near the midpoint of the back. There are several short, irregular creases or grooves on the throat similar to those found on the sperm whale (see Figs. 60, 165).

Dwarf sperm whales are dark steel gray on the back, grading to lighter gray on the sides, and fading to dull white on the belly.

May Be Confused With

Because of their tall, falcate dorsal fin, dwarf sperm whales may be confused at a distance with any of the small dolphin species. Their all-black or dark steel-gray coloration and the blunted head increase the likelihood that they can be confused with pygmy killer whales or many-toothed blackfish. They will have to be examined at close range before they can be distinguished.

Dwarf sperm whales may also be confused with pygmy sperm whales (p. 144 and Fig. 160). The two species can be differentiated by the characteristics tabularized on p. 144.

Distribution

Since it has only recently been recognized as a species distinct from the pygmy sperm whale and even more recently given a common name, records of dwarf sperm whales may have been confused with those of its close relatives. The dwarf sperm whale has been reported from at least Georgia south to St. Vincent, Lesser Antilles, and throughout the eastern and northern Gulf of Mexico. It is highly likely that this species, like the pygmy sperm whale, extends further to the north.

Stranded Specimens

Because of the distinctive characteristics of the genus, neither species of stranded _Kogia_ is likely to be confused with any other species. They can be distinguished from one another by the characteristics tabularized on p. 144.

HARBOR PORPOISE (T)

_Phocoena phocoena_ (Linnaeus 1758)

Other Common Names

Common porpoise, herring hog, puffing pig (Newfoundland and New England), Pourcils (Quebec), harbour porpoise.

Description

The harbor porpoise is the smallest cetacean species in the western North Atlantic Ocean, reaching a maximum overall length of about 5 feet (1.5 m). Its most distinctive identifying features in encounters at sea are 1) the small, chunky body; 2) the coloration, dark brown or gray on the back, fading to lighter grayish brown on the sides, often with speckling in the transition zone, and white on the belly extending farther up on the sides in front of the dorsal fin; 3) the small rounded head, lacking a distinctive beak; 4) the small, triangular dorsal fin; and 5) the shallow, inshore northerly distribution.

Natural History Notes

As the name implies, the harbor porpoise inhabits bays, harbors, river mouths, and all the relatively shallow inshore water between. Though it may travel in schools of nearly a hundred individuals, it is more often seen in pairs or in small groups of from 5 to 10 individuals. It often swims quietly at the surface. It will not ride the bow wave and is very difficult to approach closely by boat.

May Be Confused With

The harbor porpoise is not known to associate with dolphins but is sometimes seen in close proximity to fin whales and humpback whales off the Canadian coast in spring and summer. Because of its northern inshore habitat, the harbor porpoise is not likely to be confused with any other cetacean.

Distribution

Harbor porpoises are restricted to the colder waters of the western North Atlantic Ocean. They have been reported from North Carolina north to the Davis Straits and the waters of southwestern Greenland. Within this range they are probably most common in the Bay of Fundy and off southwest Greenland.

Stranded Specimens

In addition to the characteristics described above for living animals, stranded harbor porpoises can be readily identified by the small spade-shaped teeth, 22-28 per jaw.

ACKNOWLEDGMENTS

Obviously this guide could not have been produced without the cooperation of many people. Of over 450 individuals and scientific organizations contacted in 14 countries, 255 responded to our letters and well over 100 provided photographs for review and selection. We were particularly pleased that for the majority of the species found in the western North Atlantic our most difficult problem was narrowing the choices and ultimately selecting illustrations from the many good materials made available to us. Although there are far too many contributors to mention all by name, their prompt and enthusiastic responses to requests for help are gratefully acknowledged, whether or not their materials were used.

Although photo credits follow each figure, we would particularly like to cite the generosity of Marineland of Florida, Hideo Omura of the Japanese Whales Research Institute, J.G. Mead of the U.S. National Museum, K.C. Balcomb of Moclips Cetological Society, Seiji Ohsumi of the Far Seas Fisheries Research Laboratory, Jack Lentfer of the Alaskan Department of Fish and Game, the U.S. Naval Undersea Center (NUC), The University of Rhode Island, and William F. Perrin of the National Marine Fisheries Service (NMFS). Photographs by Taruski, McCann, Hain, Wheeler, and Rigley are in Winn's files. All others are in the files of Leatherwood and Caldwell. The illustrations for Figures B1 and D1 were prepared by George Galich of NUC. All other illustrations were prepared by Lois Winn.

The extensive and often tedious job of preparing black and white photographs of suitable format from the vast array of black and white and color negatives and prints and from color transparencies was accomplished at the NUC Photographic Laboratory by the able team of Domingo Sanchez, Ray Krenik, Jeanne Lucas, and Alan McPhee.

George E. Lingle and John C. Moore assisted with gathering and reviewing the literature and with cataloging and screening photo materials.

The various drafts of the manuscript were typed by Linda Thomson, Margaret Alvarez, and Sandra Nolan. Sandra Peterson assisted with proofreading the later drafts.

In preparing this guide we drew freely from the literature on cetaceans of this region and supplemented it with our own observations and with unpublished notes provided by our colleagues. A partial list of materials used, each a good source of reference material on cetaceans in general or on cetaceans of the western North Atlantic in particular, is provided in the following section, "Selected Bibliography."

All of the following colleagues read all or part of the manuscript and made useful suggestions for its improvement: K.C. Balcomb, W.C. Cummings, J.G. Mead, Hideo Omura, W.F. Perrin, F.K. Rodgers, Allen N. Saltzman, D.E. Sergeant, W.A. Watkins, A.A. Wolman, and F.G. Wood.

All of the information and photographs contributed by Lois Winn were obtained under grants from the Office of Naval Research. Funds and assistance for the preparation of intermediated drafts and logistics support for all stages of preparation of this guide were provided by Biological Systems, Inc., St. Augustine, Fla.

In addition to securing funds for the preparation and publication of this guide, Paul Sund, Platforms of Opportunity Program, NMFS, Tiburon, Calif., provided continuing help and criticism.

To these and to all who use this guide to further help knowledge about the cetaceans of the western North Atlantic, we are grateful.

SELECTED BIBLIOGRAPHY

ANDERSEN, H. T. (editor).

1969. The biology of marine mammals. Academic Press, N.Y., 511 p.

BURT, W. H.

1952. A field guide to the mammals. Houghton Mifflin Co., Boston, 200 p.

CALDWELL, D. K., and M. C. CALDWELL.

1973. Marine mammals of the eastern Gulf of Mexico. _In_ J. I. Jones, R. E. Ring, M. O. Rinkel, and R. E. Smith (editors), A summary of knowledge of the eastern Gulf of Mexico, p. III-I-1--III-I-23. State Univ. Syst. Fla. Inst. Oceanogr., St. Petersburg, Fla.

CALDWELL, D. K., and F. B. GOLLEY.

1965. Marine mammals from the coast of Georgia to Cape Hatteras. J. Elisha Mitchell Sci. Soc. 81:24-32.

CALDWELL, D. K., H. NEUHAUSER, M. C. CALDWELL, and H. W. COOLIDGE.

1971. Recent records of marine mammals from the coasts of Georgia and South Carolina. Cetology 5:1-12.

FRASER, F. C. 1937. Whales and dolphins. _In_ J. R. Norman and F. C. Fraser, Giant fishes, whales and dolphins, p. 201-349. Putnam and Sons, Lond. [There are several editions of this work, all with the same information.]

1966. Guide for the identification and reporting of stranded whales, dolphins and porpoises on the British coasts. Br. Mus. Nat. Hist., Lond., 34 p.

GOLLEY, F. B.

1966. South Carolina mammals. The Charleston Museum, Charleston, S.C., xiv + 181 p.

GUNTER, G.

1954. Mammals of the Gulf of Mexico. _In_ P. S. Galtsoff (coordinator), Gulf of Mexico, its origin, waters, and marine life, p. 543-567. U.S. Fish Wildl. Serv., Fish. Bull. Vol. 55.

HALL, E. R., and K. R. KELSON.

1959. Order cetacea--cetaceans. _In_ The mammals of North America, 2:806-840. Ronald Press, N.Y.

HERSHKOVITZ, P.

1966. Catalog of living whales. Bull. U.S. Natl. Mus. 246, 259 p.

KELLOGG, R.

1940. Whales, giants of the sea. Natl. Geogr. Mag. 77:35-90.

LAYNE, J. N.

1965. Observations on marine mammals in Florida waters. Bull. Fla. State Mus., Biol. Sci. 9:131-181.

LEATHERWOOD, S., W. E. EVANS, and D. W. RICE.

1972. The whales, dolphins, and porpoises of the eastern north Pacific. A guide to their identification in the water. Nav. Underseas Cent., Tech. Publ. 282, 175 p.

LOWERY, G. H., JR.

1974. The mammals of Louisiana and its adjacent waters. Louisiana State Univ. Press, Baton Rouge, 565 p.

MITCHELL, E. D.

1973. The status of the world's whales. Nat. Can. 2(4):9-25.

MOORE, J. C.

1953. Distribution of marine mammals to Florida waters. Am. Midl. Nat. 49:117-158.

NORRIS, K. S. (editor).

1966. Whales, dolphins, and porpoises. Univ. California Press, Berkeley, 789 p.

PALMER, R. S.

1954. The mammal guide. Doubleday and Co., N.Y., 384 p.

RICE, D. W.

1967. Cetaceans. _In_ S. Anderson and J. K. Jones (editors), Recent mammals of the world; a synopsis of families, p. 291-324. The Ronald Press, N.Y.

RICE, D. W., and V. B. SCHEFFER.

1968. A list of the marine mammals of the world. U.S. Fish Wildl. Serv., Spec. Sci. Rep. Fish. 579, 16 p.

RIDGEWAY, S. H. (editor).

1972. Mammals of the sea; biology and medicine. Charles C. Thomas, Springfield, Ill., xiii + 812 p.

SCHEVILL, W. E.

1974. The whale problem. Harvard Univ. Press, Cambridge, Mass., 297 p.

SERGEANT, D. E., and H. D. FISHER.

1957. The smaller Cetacea of eastern Canadian waters. J. Fish. Res. Board Can. 14:83-115.

SERGEANT, D. E., A. W. MANSFIELD, and B. BECK.

1970. Inshore records of Cetacea of eastern Canada, 1949-68. J. Fish. Res. Board Can. 27:1903-1915.

SLIJPER, E. J.

1962. Whales. Hutchinson and Co., Ltd., Lond., 475 p. [There is also an American edition.]

TOMILIN, A. G.

1967. Cetacea. Mammals of the U.S.S.R. and adjacent countries. Isr. Program Sci. Transl., Jerusalem, Vol. IX, 717 p. [A compilation of worldwide data, originally published in Russian.]

TOWNSEND, C. H.

1935. The distribution of certain whales as shown by logbook records of American whaleships. Zoologica (N.Y.) 19:1-50.

TRUE, F. W.

1889. Contributions to the natural history of the cetaceans, a review of the family Delphinidae. Bull. U.S. Natl. Mus. 36:1-192.

WALKER, E. P.

1964. Mammals of the world. The Johns Hopkins Press, Baltimore, p. 1083-1145. [Cetaceans. There is also a second, revised edition of this work, and a third, revised edition is planned.]

APPENDIX A

TAGS ON WHALES, DOLPHINS, AND PORPOISES

Field studies of cetaceans are very difficult. First, it is extremely hard to be positive that an individual or a group of animals is the same from one encounter to the next. This means that it is nearly impossible to determine, for example, whether herds of animals are resident in an area or only seasonal visitors. Without information of this kind, determinations vital to population management, such as sizes of populations and natural ranges, are impossible to make.

Secondly, as we frequently point out in this guide, individual cetaceans are usually visible to a surface observer only during the brief moments when they break the air-water interface to breathe. The majority of their vital activities (e.g., feeding, reproduction, communication, establishing and maintaining position within the herd, and defending against natural enemies) take place primarily below the surface, well out of view to a surface observer.

In recent years, in an attempt to overcome some of these problems, scientists have been placing markers on various species of cetaceans and monitoring their movements. The following brief summary of major methods of tagging cetaceans is provided to acquaint the reader with markers he may expect to see in the western North Atlantic.

Static Tags

Since their development in the mid-1920's, numerous Discovery marks (small stainless steel projectiles with identifying information stamped on them) have been shot into commercially valuable species by means of a shotgun. The recovery of these marks from whales subsequently killed in the whaling industry has provided valuable information on the movement patterns and on basic aspects of the growth and development of harvested species of whales. Discovery marks are limited, however, because they are not visible in a living animal. Reduction in whaling activities will bring about a significant reduction in their use.

More recent tagging developments relate to marks which will be visible on a free-swimming animal. Large whales, for instance, may be tagged with color-coded streamers, such as that shown in Appendix Figure A2. The tags, which are modified versions of the spaghetti tags first constructed for use on fishes, consist of a small stainless steel head for attachment to the blubber and a colorful streamer (sometimes stamped with information on agencies to which tags should be returned) which is visible above the surface of the animal. These tags may be applied by using either a pole applicator or a crossbow and crossbow bolts. Both applicators are equipped with a stop to limit the depth of penetration into the animal's blubber. Extensive experimentation indicates that the tags do not harm the animals and that their application is not traumatic. With the continued reduction in whaling activity, it is hoped that the use of such markers in the study of movements of big whales will be increased.

Because they often ride the bow wave of a moving vessel, thereby making themselves accessible for tagging and capture, small porpoises and dolphins have been tagged with a greater variety of marks than large whales. In recent years, at least three kinds of static tags, including spaghetti streamers, have been placed on small and medium-sized cetaceans.