HOW TO USE THE GUIDE

To Identify Animals at Sea

The three major sections of the guide (i.e., large, medium, and small whales) 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:

1. First estimate the animal's size and determine whether or not it has a dorsal fin.

2. Note also any distinctive features of body shape and coloration and observe its general behavior, including swimming, blowing, and diving characteristics. It should be noted that coloration may vary somewhat at sea, depending on light conditions and water clarity. For example, animals which appear dark gray or black at the surface or when dead may appear brown in good light or when submerged. Making a brief sketch at this point may aid in identifying the animal or in later recalling its distinctive features.

3. Using the directory, locate the section to which the animal probably belongs.

4. Then, for more detailed information, consult the section indicated. There you will find a more complete discussion of the animal's range, size, and distinctive characteristics. In addition, you will find a brief discussion distinguishing it from animals with which it is likely to be confused in the field.

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(s) he sees at the time of the encounter rather than depending on his recall at a later time (see p. 160). 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 (Table 1), or to the tables on the numbers and descriptions of teeth, for toothed whales (Table 2).

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.

Species common name Species scientific name Page of species account Ranges in tooth counts Remarks

Upper Lower

Sperm whalePhyseter catodon57018-25Ten to sixteen upper teeth rarely emerge; lower teeth fit into sockets in upper jaw.

Northern bottlenosed whaleHyperoodon ampullatus6702(2)[A]At tip of lower jaw; sometimes second pair behind first.

Goosebeaked whaleZiphius cavirostris7002[A]At tip of lower jaw.[B]

True's beaked whaleMesoplodon mirus7702[A]At tip of lower jaw.[B]

Antillean beaked whaleMesoplodon europaeus7802[A]At suture of mandible. One-third of way from tip of snout to gape.[B]

Dense-beaked whaleMesoplodon densirostris8002[A]On prominences near corner of mouth; oriented backwards.[B]

North Sea beaked whaleMesoplodon bidens8202[A]About halfway from tip of snout to gape.[B]

Killer whaleOrcinus orca8410-1210-12Prominent; curved and oriented backwards and inwards; pointed.

False killer whalePseudorca crassidens888-118-11Prominent; pointed and curved.

Atlantic pilot whaleGlobicephala melaena918-108-10— —

Short-finned pilot whaleGlobicephala macrorhyncha947-97-9— —

GrampusGrampus griseus9600-7Near front of jaw; may have fallen out in older specimens; sometimes teeth in upper jaw.

BelugaDelphinapterus leucas998-118-9— —

NarwhalMonodon monoceros10220[A]One (rarely both) grows up to 9 ft (2.5 m) tusk which has left-hand (sinestral) spiral.

Spotted dolphinStenella plagiodon10430-3628-35— —

Bridled dolphinStenella frontalis10829-3433-36— —

Spinner dolphinStenella longirostris11046-6546-65— —

Striped dolphinStenella coeruleoalba11343-5043-50— —

Saddleback dolphinDelphinus delphis11640-5040-50— —

Fraser's dolphinLagenodelphis hosei12038-4438-44— —

Atlantic white-sided dolphinLagenorhynchus acutus12330-4030-40Some specimens have more teeth in upper than in lower jaw.

White-beaked dolphinLagenorhynchus albirostris12622-2822-28— —

Atlantic bottlenosed dolphinTursiops truncatus12820-2618-24— —

Guiana dolphinSotalia guianensis13226-3526-35— —

Rough-toothed dolphinSteno bredanensis13520-2720-27Crown is sometimes marked with many fine vertical wrinkles.

Pygmy killer whaleFeresa attenuata1388-1310-13Many specimens have fewer teeth on right than on left side.

Many-toothed blackfishPeponocephala electra14222-2521-24— —

Pygmy sperm whaleKogia breviceps144012-16Rarely 10 or 11; curved back and inwards; fit into sockets in upper jaw.

Dwarf sperm whaleKogia simus1480-38-11Rarely 13; curved back and in; sharply pointed; fit into sockets in upper jaw. Rarely has 1-3 upper teeth as well.

Harbor porpoisePhocoena phocoena15022-2822-28Spade shaped, laterally compressed, and relatively small.

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.

Species common name Species scientific name Page of species account Maximum body size[C] ft(m) Number of baleen plates/side Maximum dimensions of plates Color of baleen Mean No. of bristles /cm. Numbers of ventral grooves Relative lengths of ventral grooves

Length Width base

ft/in. cm ft/in. cm

Blue whale Balaenoptera musculus 19 85 (26.0) 270-395 33" 84 12" 30 All black with black bristles. 10-30 55-88 At least to navel.

Fin whale Balaenoptera physalus 26 79 (24.0) 262-473 29" 72 12" 30 Dark gray to bluish gray; one-fifth to one-third of right front is whitish. 10-35 56-100 At least to navel.

Sei whale Balaenoptera borealis 32 62 (19.0) 318-340 31" 78 15" 39 Ash black with blue tinge and fine, light bristles; some near front may be light. 35-60 38-56 End far short of navel.

Bryde's whale Balaenoptera edeni 37 46 (14.0) 250-300? 17" 42 10" 24 Slate gray with dark bristles. 15-35 40-50 At least to navel.

Humpback whale Megaptera novaeangliae 40 53 (16.0) 270-400 24" 60 5" 13 Ash black to olive brown; sometimes whitish; bristles grayish white. 10-35 14-22 At least to navel.

Bowhead whale Balaena mysticetus 49 65 (19.8) 325-360 14' 414 14" 36 Black; anterior side of some is whitish; bristles black. ? None present. XX

Right whale Eubalaena glacialis 52 53 (16.0) 250-390 7.3' 223 12" 30 Dirty or yellowish gray; some anterior plates all or part white. 35-70 None present. XX

Minke whale Balaenoptera acutorostrata 63 31 (10.0) 300-325 8" 21 4" 10 White to yellowish white. Posterior plates may be brown or black. 15-25 50-70 End short of navel; often just behind flippers.