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A bibliography of useful references on cetaceans in general and cetaceans of this region in particular and a directory to species accounts are included.

HOW TO USE THE GUIDE

To Identify Animals at Sea

The three major sections of the guide are preceded by a directory to species accounts, which is a summary of the most obvious characteristics of each species and in which summary statements about each characteristic are arranged in parallel order. To use the guide to identify living animals observed at sea, a person or persons should:

This guide will probably work best if, in advance of attempting to use the key in the field, the reader will familiarize himself with the general outline, with characters or behaviors to note, and with the locations of the various species accounts. It will also help if he schools himself to ask a series of questions about the animal he sees at the time of the encounter rather than depending on his recall at a later time . As we have emphasized several times in this guide, positive identification of cetaceans at sea can only occasionally be made on the basis of a single characteristic. Therefore, the greater the amount of pertinent evidence an observer obtains, the greater the likelihood he can make a reliable identification.

To Identify Stranded Animals

Stranded animals can best be identified by referring to Appendix C and its associated tables, making a preliminary determination and then consulting the species accounts in the main body of the book for verification of the identification. As noted in that appendix, if the animal is recently stranded, identification can be made using any of the externally visible characteristics described for the living species at sea. But even if the animal is in an advanced stage of decomposition, it can usually be identified by referring to the key and to the numbers and descriptions of baleen plates, for all baleen whales, and the numbers and relative lengths of ventral grooves, for all balaenopterine whales , or to the tables on the numbers and descriptions of teeth, for toothed whales .

To Record and Report Information

As discussed in the preface, though learning to identify the whales, dolphins, and porpoises one sees may be exciting in itself, many persons may want to participate in the accumulation of data on these interesting animals by routinely reporting their observations to scientists who are actively studying them and who can make immediate use of the information. The following may help these persons:

Suggestions for making and recording observations of cetaceans at sea and sample data forms are included in Appendix C. Similar suggestions for taking and recording data on stranded cetaceans are included in Appendix D. For both types of data, blank data forms located after the appendices may be photocopied in bulk for use in the field.

Completed data forms and all associated information for sightings at sea should be forwarded to the Platforms of Opportunity Program, National Marine Fisheries Service, Tiburon, CA 94920, or to one of the authors of this guide. From there, they will be made available to scientists actively studying the cetaceans of a given species or geographical area.

Completed data forms and all associated information for observations of stranded cetaceans should be forwarded to the Division of Mammals, U.S. National Museum, Washington, DC 20560, to one of the authors of this guide, or to one of the regional laboratories listed in Appendix E. These persons have, in turn, been encouraged to keep a free flow of information among them.

Table 1. Ranges in Numbers of Teeth in Each Upper and Lower Jaw of Western North Atlantic Odontocetes.

Table 2. Body Size; Numbers, Maximum Dimensions and Descriptions of Baleen Plates; and Numbers and Relative Lengths of Ventral Grooves of W. N. Atlantic Mysticetes.

DIRECTORY TO SPECIES ACCOUNTS

LARGE WHALES

With a Dorsal Fin

All five species of large whales with a dorsal fin belong to the same major baleen whale group, the balaenopterid whales or rorquals. All are characterized by the presence of a series of ventral grooves, usually visible on stranded specimens and the length and number of which are diagnostic to species. In addition, all species, with the exception of the humpback whale, have at least one distinctive ridge along the head from just in front of the blowhole to near the tip of the snout. In Bryde's whale, the single head ridge characteristic of the other rorquals is supplemented by two auxiliary ridges, one on each side of the main ridge.

At sea, these whales often appear very similar and must be examined carefully before they can be reliably identified.

In general, though the characteristics of behavior may vary from one encounter to the next, based on the activities in which the animal is engaged, whales in this group may be distinguished from each other on the basis of differences in 1) the size, shape, and position of the dorsal fin and the timing of its appearance on the surface relative to the animal's blow ; 2) the height of body in the area of the dorsal fin, relative to the size of the dorsal fin, which is exposed as the animal sounds; 3) sometimes the blow rate and movement patterns; and 4) the shape and color of the head.

Despite variability in behavior by members of the same species from one encounter to the next, an observer can greatly increase the reliability of his identification by forming the habit of working systematically through a set of characteristics for the species rather than depending on any single characteristic.

Body very large, up to 85 feet long. Body basically bluish with mottlings of grayish white. Baleen all black. Head broad and nearly U-shaped, viewed from above. Head flat in front of blowhole, viewed from side. Dorsal fin small , triangular to moderately falcate, in the last one-third of back. Distribution primarily from temperate seas to pack ice; rare in tropics. Distribution more northerly during summer. Flukes occasionally raised slightly on long dive.

Body large, up to 79 feet long. Body mostly dark gray or brownish gray; undersides of flukes and flippers and belly white; grayish-white chevron frequently on back behind head. Right lower lip white; right upper lip sometimes white; left lip dark. Head V-shaped, viewed from above. Right front one-third to one-fifth of baleen plates, yellowish white. Other baleen bluish gray with yellowish-white stripes. Dorsal fin to 24 inches , slightly more than one-third forward from tail; forms angle of less than 40? with back. Distribution extensive but not very common near pack ice and in tropics. Distribution more northerly during summer. Flukes not raised on dive.

Body up to 62 feet long. Body appears shiny; dark gray on back, often with ovoid grayish-white scars; white on front of belly; undersides of flippers and flukes dark. Baleen grayish or ash black with fine, light-gray bristles. Dorsal fin to 24 inches , strongly falcate, well more than one-third forward from tail; forms angle of more than 40? with back. Distribution extensive; are not very common in cold waters and may have a greater tendency than fin whales to enter tropical waters. Distribution more northerly in summer. Flukes not raised on dive.

Body up to 46 feet long. Body dark gray overall. Head has series of three ridges from area of blowhole to snout. Baleen slate gray with coarse dark bristles. Dorsal fin to 18 inches , falcate, well more than one-third forward from tail, often irregularly worn on rear margin. Distribution primarily tropical and southern temperate. Flukes not raised on dive.

Body up to 53 feet long. Body dark gray with irregular white area on belly; flippers white; underside of flukes often has varying amounts of white. Head in front of blowhole flat and covered with knobs. Baleen dark gray to black with olive-black bristles. Dorsal fin small, quite variable in shape, usually hooked, located on a step or hump, in last one-third of back. Flippers very long , white, and scalloped on leading edge. Distribution at least New England to Iceland and Greenland during summer. Distribution to shallow tropical banks, winter and spring. Flukes often scalloped on trailing edges and sometimes raised on dive.

NOTE: Because of its small adult size, usually less than 30 feet , another member of the rorqual family, the minke whale, is included with the medium-sized whales in this guide. Features by which it may be distinguished from all other rorquals are discussed in the species account.

Further, inasmuch as the dorsal fin of the humpback whale is highly variable in shape, positive identification may require reference to the sperm whale , which, though the sperm whale has been classified with species without dorsal fin, has a rather distinct dorsal hump, particularly noticeable when the animal arches the back and tail to begin a long dive.

Without a Dorsal Fin

There are three species of large whales without a dorsal fin in the western North Atlantic Ocean. Two of these, the bowhead or Greenland whale, and its more widely distributed close relative the right whale, are baleen whales. The third, the sperm whale, is a toothed whale. The first two have relatively smooth backs without even a trace of a dorsal fin. The sperm whale has a humplike low, thick, dorsal ridge, which, from certain views, particularly when the animal is humping up to begin a dive, may be clearly visible and look like a fin. But because the profile of that hump and the knuckles which follow it are often not very prominent in this species, it has been classified with the finless big whales.

All three species are characterized by very distinctive blows or spouts. In both the bowhead and the right whales, the projection of the blow upward from two widely separated blowholes assumes a very wide V-shape with two distinct columns, which may be seen when the animals are viewed from front or back. Though this character may be visible under ideal conditions in many of the other baleen whales species as well, it is exaggerated and uniformly distinct in the bowhead and right whales and may be used as one of the primary key characters. In the sperm whale, the blow emanates from a blowhole which is displaced to the left of the head near the front and projects obliquely forward to the animal's left. This blow seen under ideal conditions positively labels a large whale as a sperm whale.

Remember, however, that wind conditions may affect the disposition and duration of the blow of any species and that a single character alone is seldom sufficient to permit positive identification.

Body to 65 feet long. Body dark; back smooth. Chin and belly often white. Head lacks callosities. Baleen dark gray with gray fringes; to 12 feet or more. Upper jaw and lower lip strongly arched. Two blowholes clearly separated. Blow projects upward in wide V-shape. Distribution restricted to Arctic waters south to Davis Straits. Flukes raised on longer dives.

Body to 53 feet long. Body from dark to light gray and mottled; back smooth; chin and belly usually white. Head and lower jaw covered with callosities . Baleen usually dark gray with dark fringes; to 7.2 feet . When animals swim, mouth agape, near surface; baleen sometimes appears pale brownish to yellowish gray in color. Upper jaw and lower lip strongly arched. Two blowholes clearly separated. Blow projects upward in wide V-shape. Distribution extends from Iceland south at least to Florida and reported from Texas. Flukes raised on longer dives.

Body to 69 feet long; males grow significantly larger than females. Body dark grayish brown to brown; wrinkled in appearance. Back has rounded hump followed by knuckles. Head boxlike, comprises up to 40% of body length. From 18 to 25 functional teeth in each side of narrow lower jaw. Single blowhole on left of head at front. Blow projects forward obliquely from head and to left. Distribution extends from tropics to Arctic; adult males distributed farther north. Flukes raised on longer dives.

MEDIUM-SIZED WHALES

With a Dorsal Fin

There are 11 species of medium-sized whales with a dorsal fin known from the western North Atlantic. These species, taking many diverse forms, range in maximum adult size from about 13 feet to about 33 feet . This group includes such widely distributed and frequently encountered species as the pilot whales, false killer whales, and minke whales, and such rarely encountered and poorly known species as the various "beaked whales" .

Aside from their common inclusion within the stated size range and the presence of a dorsal fin in all species , these species have no diagnostic field characteristics in common. Therefore, each is discussed in detail and is placed in the text in near proximity to those species with which it is likely to be confused in the field.

Body to 30 feet , or more, long. Body black or dark gray; area of gray shading on each side just in front of and below dorsal fin. Flippers have transverse white band. Head very sharply V-shaped viewed from above. Dorsal fin falcate and distinct; usually appears simultaneous with blow. Blow often low and indistinct. Distribution polar, temperate, and tropical; frequently coastal. Often curious about boats. Flukes not raised on dive.

Body to 32 feet long. Body of young uniformly chocolate brown; body of adults brown with cream or yellow blotches. Head bulbous in adults and white in larger animals; has distinct beak. Dorsal fin falcate and distinct, in last one-third of back. Distribution north temperate and Arctic-offshore. Often curious about boats. Flukes large, rarely notched; occasionally raised on long dive.

Body to at least 23 feet long. Body from dark gray or brown to rust or fawn and splotched with white; eyes dark. Head of large males white. Back frequently scarred with numerous scratches, presumably tooth marks. Dorsal fin falcate and distinct, in last one-third of back. Distribution primarily tropical; extends to temperate. Flukes light beneath, sometimes shallowly notched; often raised on dive.

Body to 16-22 feet long. Body color black to dark gray. Back frequently scarred. Dorsal fin position varies with species. Distribution varies with species. Flukes not usually distinctly notched.

Body to at least 30 feet long. Body black with sharply demarcated white belly and oval white patch above and behind eye; gray saddle behind dorsal fin. Body chunky. Dorsal fin in males can be very tall, sometimes 6 feet . Dorsal fin in females and immature animals up to 3 feet , distinctly falcate. Distributed from tropics to Arctic; most common in colder waters. Often seen in shallow bays and rivers and near shore. Flukes may be raised on dive.

Body to at least 18 feet long. Body black . Body slender. Head small, tapering. Large prominent teeth frequently visible at sea. Flippers have distinct hump on leading edge. Dorsal fin to 14 inches , falcate, and from rounded to pointed on tip. Distribution pelagic tropical to warm temperate seas. Frequently ride bow waves.

Body to at least 22 feet long. Body black with light gray, anchor-shaped area on chest; gray saddle sometimes seen behind dorsal fin. Head becoming more bulbous with age, somewhat squarish in adult males viewed from above. Tail humped. Flippers long , sickle-shaped. Dorsal fin broad-based, falcate to flaglike, in front half of back. Distribution primarily north temperate--about Hatteras north. Flukes not usually raised on dive.

Body to at least 17.5 feet long. Body black with indistinct light gray area on chest; saddle behind dorsal fin. Head becoming more bulbous with age; square in large adult males viewed from above. Flippers relatively short . Dorsal fin broad-based, falcate to flaglike, in front half of back. Distribution tropical and warm temperate; from about Hatteras south. Flukes not usually raised on dive.

Body to at least 13 feet long. Body of newborn light gray; darkens with age. Body of adults light gray or white; scarred with numerous scratches. Head blunted, not beaked. Forehead has vertical crease in center. Dorsal fin less than 15 inches , rather erect and distinct, and dark even in light adults. Distribution tropical to temperate. Rarely ride bow wave.

Without a Dorsal Fin

The only two species of medium-sized cetaceans in the western North Atlantic which have no dorsal fin, the Beluga or white whale and the Narwhal, share such limited common range, well outside the theater of normal boating traffic, that they are generally infrequently encountered.

Both species are easily identifiable when seen.

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