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Introduction 1 Classification of cetaceans 1 Dolphin or porpoise 5 Organization of the guide 5 How to use the guide 7 To identify animals at sea 7 To identify stranded animals 7 To record and report information 7 Directory to species accounts: Large whales: With a dorsal fin 10 Without dorsal fin 13 Medium-sized whales: With a dorsal fin 14 Without dorsal fin 15 Small whales, dolphins, and porpoises with a dorsal fin 16 Species accounts: Large whales with a dorsal fin: Blue whale 19 Fin whale 26 Sei whale 32 Bryde's whale 37 Humpback whale 40 Large whales without dorsal fin: Bowhead whale 49 Right whale 52 Sperm whale 57 Medium-sized whales with a dorsal fin: Minke whale 63 Northern bottlenosed whale 67 Goosebeaked whale 70 Other beaked whales 74 True's beaked whale 77 Antillean beaked whale 78 Dense-beaked whale 80 North Sea beaked whale 82 Killer whale 84 False killer whale 88 Atlantic pilot whale 91 Short-finned pilot whale 94 Grampus 96 Medium-sized whales without dorsal fin: Beluga 99 Narwhal 102 Small whales, dolphins, and porpoises with a dorsal fin: Atlantic spotted dolphin 104 Bridled dolphin 108 Spinner dolphin 110 Striped dolphin 113 Saddleback dolphin 116 Fraser's dolphin 120 Atlantic white-sided dolphin 123 White-beaked dolphin 126 Atlantic bottlenosed dolphin 128 Guiana dolphin 132 Rough-toothed dolphin 135 Pygmy killer whale 138 Many-toothed blackfish 142 Pygmy sperm whale 144 Dwarf sperm whale 148 Harbor porpoise 150 Acknowledgments 152 Selected bibliography 152

Appendix A, Tags on whales, dolphins, and porpoises 154

Appendix B, Recording and reporting observations of cetaceans at sea 160

Appendix C, Stranded whales, dolphins, and porpoises; with a key to the identification of stranded cetaceans of the western North Atlantic 163

Appendix D, Recording and reporting data on stranded cetaceans 169

Appendix E, List of institutions to contact regarding stranded cetaceans 171

The National Marine Fisheries Service does not approve, recommend or endorse any proprietary product or proprietary material mentioned in this publication. No reference shall be made to NMFS, or to this publication furnished by NMFS, in any advertising or sales promotion which would indicate or imply that NMFS approves, recommends or endorses any proprietary product or proprietary material mentioned herein, or which has as its purpose an intent to cause directly or indirectly the advertised product to be used or purchased because of this NMFS publication.

Whales, Dolphins, and Porpoises of the Western North Atlantic

A Guide to Their Identification

STEPHEN LEATHERWOOD, DAVID K. CALDWELL, and HOWARD E. WINN

with special assistance by William E. Schevill and Melba C. Caldwell

ABSTRACT

This field guide is designed to permit observers to identify the cetaceans they see in the western North Atlantic, including the Caribbean Sea, the Gulf of Mexico, and the coastal waters of the United States and Canada. The animals described are grouped not by scientific relationships but by similarities in appearance in the field. Photographs of the animals in their natural environment are the main aids to identification.

A dichotomized key is provided to aid in identification of stranded cetaceans and appendices describe how and to whom to report data on live and dead cetaceans.

INTRODUCTION

All whales, dolphins, and porpoises belong to an order or major scientific group called the Cetacea by scientists. They are all mammals which have undergone extensive changes in body form and function to cope with a life spent entirely in the water. The breathing aperture, called a blowhole or blowholes, has migrated to the top of the head to facilitate breathing while swimming; the forward appendages have become flippers; the hind appendages have nearly disappeared, they remain only as small traces of bone deeply imbedded in the muscles. Propulsion is provided by fibrous, horizontally flattened tail flukes.

Scientists recognize two suborders of living cetaceans: the whalebone whales, suborder Mysticeti, and the toothed whales, suborder Odontoceti. The two groups are separated in the following ways:

BALEEN OR WHALEBONE WHALES. These animals are called whalebone whales because when fully formed instead of teeth they have up to 800 or more plates of baleen or whalebone depending from the roof of the mouth. They use these plates to strain their food, which consists of "krill" and/or small schooling fish, by taking water into the mouth and forcing it out through the overlapping fringes of the baleen plates. Baleen whales are externally distinguishable from toothed whales by having paired blowholes. There are eight species of baleen whales in the western North Atlantic, ranging in size from the minke whale to the blue whale .

TOOTHED WHALES. Unlike the baleen whales, the toothed whales do have teeth after birth. The teeth vary in number from 2 to over 250, though they may sometimes be concealed beneath the gum. In addition, toothed whales have only a single blowhole. This group includes the animals commonly called dolphin or porpoise as well as some commonly called whales . There are currently about 30 species of toothed whales known from the western North Atlantic, ranging in maximum adult size from the common or harbor porpoise, which is approximately 5 feet long, up to the sperm whale which reaches a length of 68 feet . Several other species which are expected to be found in this region, though they have not yet been reported, are also included in this guide.

CLASSIFICATION OF CETACEANS

In addition to the two suborders , the cetacean order contains numerous families, genera, and species. Each of these groupings represents a progressively more specialized division of the animals into categories on the basis of similarities in their skulls, postcranial skeletons, and external characteristics. The discipline which concerns itself with naming an animal and assigning it to its appropriate scientific category is known as taxonomy. An example of the classification of a cetacean species is shown in the following:

SCIENTIFIC CLASSIFICATION OF THE ATLANTIC BOTTLENOSED DOLPHIN

Kingdom: Animalia all animals

Phylum: Chordata having at some stage a notochord, the precursor of the backbone

Subphylum: Vertebrata animals with backbones--fishes, amphibians, reptiles, birds, and mammals

Class: Mammalia animals that suckle their young

Order: Cetacea carnivorous, wholly aquatic mammals: whales, including dolphins and porpoises

Suborder: Odontoceti toothed whales as distinguished from Mysticeti, the baleen whales

Family: Delphinidae dolphins

Genus: Tursiops bottlenosed dolphins

Species: truncatus Atlantic bottlenosed dolphin

Although classification of many species is still in a state of flux, the classification of western North Atlantic cetaceans followed in this guide is as follows:

Page of synoptic account of the species

Order Cetacea

Suborder Mysticeti--Baleen whales

Family Balaenopteridae--Rorquals

Family Balaenidae--Right whales

Suborder Odontoceti--Toothed whales

Family Ziphiidae

Family Physeteridae

Family Monodontidae

Family Stenidae

Family Delphinidae

Family Phocoenidae

This tentative classification follows an unpublished list by W.E. Schevill and E.M. Mitchell currently under review. The scientific names are followed by the name of the individual who named the species and the year of naming, and then by the common name most often used in the western North Atlantic. It may be noted that some of the authors are in parentheses. This indicates that though the species name has remained the same since the date of naming the species has since been assigned to another genus. Because the species are not arranged in taxonomic order in this field guide, the page of the synoptic account of each is provided in the column to the right.

DOLPHIN OR PORPOISE

Detailed treatment of the relative merits of the various terminologies is inappropriate here. Furthermore, it is our opinion that the usage of the terms dolphin, porpoise, and whale as part of the common names of cetaceans is largely a matter of personal preference.

ORGANIZATION OF THE GUIDE

The differences between baleen and toothed whales are easy enough to see in animals washed up on the beach or maintained in a tank at a zoo or aquarium. But since an animal at sea can seldom be examined that closely, its most obvious characteristics may be its overall size, the presence or absence of a dorsal fin, its prominent coloration or markings, its general behavior, or its swimming, blowing, and diving characteristics. For that reason, regardless of their scientific relationships, all the whales, dolphins, and the one porpoise covered in the main text of this guide are divided into three groups. Those over 40 feet long are discussed in the section on Large Whales, those from 13 to 40 feet in the Medium-Sized Whale, and those less than 13 feet in the Small Whales, Dolphins, and Porpoise . There are no small whales, dolphins, or porpoises in this region without a dorsal fin. Each section is further divided into those animals with a dorsal fin and those without. From that point, animals likely to be confused in the field are grouped together and the important differences between them are discussed.

The synoptic accounts of the species are followed by five appendices: Appendix A discusses and illustrates man-made and applied tags and natural markings on cetaceans and their importance in studies of natural history. Appendix B discusses the data which are most important to record in observations of cetaceans at sea, gives examples, and provides blank sighting forms. Appendix C discusses possible causes of cetacean strandings and the manner in which stranded animals should be handled and adds a key and tables to aid in identifying stranded cetaceans. Appendix D provides guidelines for collecting data on stranded cetaceans and provides forms and specific instructions for taking standard measurements. Appendix E lists institutions to be contacted in the event of a cetacean stranding or for information.

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

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