Part 2
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 (12.2 m) long are discussed in the section on Large Whales, those from 13 to 40 feet (4.0 to 12.2 m) in the Medium-Sized Whale, and those less than 13 feet (4.0 m) in the Small Whales, Dolphins, and Porpoise (with a dorsal fin). 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 ill.u.s.trates 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 inst.i.tutions 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.
[Ill.u.s.tration: Figure 5.--A humpback whale lying on its left side on the deck of a Canadian whaling station. Note the fringes of baleen suspended from the roof of the mouth. (_Photo by J. G. Mead_.)]
[Ill.u.s.tration: Figure 6.--Atlantic bottlenosed dolphin mother and calf from northeastern Florida. Note the single open blowhole, a characteristic that marks these animals as toothed whales. (_Photo courtesy of Marineland of Florida._)]
[Ill.u.s.tration: Figure 7.--The open mouth of an Atlantic bottlenosed dolphin from the northeastern Gulf of Mexico. All toothed whales have teeth, which are used primarily for grasping rather than for chewing.
The number varies from 2 to over 250, though they are buried beneath the gums in females and immature animals of several species, take peculiar form in one (narwhal), and are extensively worn in others. (_Photo by D.
K. Caldwell._)]
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 a.s.sociated 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 partic.i.p.ate in the acc.u.mulation 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 a.s.sociated 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 a.s.sociated 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.
[P] = Page of species account ------------------------------------------------------------------------------
Ranges in
tooth
counts
Species
-----+-----
Species common name
scientific name
[P]
Upper
Lower
Remarks --------------------+----------------+---+-----+-----+------------------------ Sperm whale
_Physeter_
57
0
18-25
Ten to sixteen upper
_catodon_
teeth _rarely_ emerge;
lower teeth fit into
sockets in upper jaw.
Northern
_Hyperoodon_
67
0
2(2)
At tip of lower jaw; bottlenosed whale
_ampullatus_
[A]
sometimes second
pair behind first.
Goosebeaked whale
_Ziphius_
70
0
2[A]
At tip of lower jaw.[B]
_cavirostris_
True's beaked whale
_Mesoplodon_
77
0
2[A]
At tip of lower jaw.[B]
_mirus_
Antillean beaked
_Mesoplodon_
78
0
2[A]
At suture of mandible.
whale
_europaeus_
One-third of way
from tip of snout to
gape.[B]
Dense-beaked whale
_Mesoplodon_
80
0
2[A]
On prominences near
_densirostris_
corner of mouth;
oriented backwards.[b]
North Sea beaked
_Mesoplodon_
82
0
2[A]
About halfway from whale
_bidens_
tip of snout to
gape.[B]
Killer whale
_Orcinus orca_
84
10-12
10-12
Prominent; curved and
oriented backwards
and inwards; pointed.
False killer whale
_Pseudorca_
88
8-11
8-11
Prominent; pointed
_cra.s.sidens_
and curved.
Atlantic pilot whale
_Globicephala_
91
8-10
8-10
-- --
_melaena_
Short-finned pilot
_Globicephala_
94
7-9
7-9
-- -- whale
_macrorhyncha_
Grampus
_Grampus_
96
0
0-7
Near front of jaw;
_griseus_
may have fallen out
in older specimens;
sometimes teeth in
upper jaw.
Beluga
_Delphinapterus_
99
8-11
8-9
-- --
_leucas_
Narwhal
_Monodon_
102
2
0[A]
One (rarely both)
_monoceros_
grows up to 9 ft
(2.5 m) tusk which
has left-hand
(sinestral) spiral.
Spotted dolphin
_Stenella_
104
30-36
28-35
-- --
_plagiodon_
Bridled dolphin
_Stenella_
108
29-34
33-36
-- --
_frontalis_
Spinner dolphin
_Stenella_
110
46-65
46-65
-- --
_longirostris_
Striped dolphin
_Stenella_
113
43-50
43-50
-- --
_coeruleoalba_
Saddleback dolphin
_Delphinus_
116
40-50
40-50
-- --
_delphis_
Fraser's dolphin
_Lagenodelphis_
120
38-44
38-44
-- --
_hosei_
Atlantic white-sided
_Lagenorhynchus_
123
30-40
30-40
Some specimens have dolphin
_acutus_
more teeth in upper
than in lower jaw.
White-beaked dolphin
_Lagenorhynchus_
126
22-28
22-28
-- --
_albirostris_
Atlantic bottlenosed
_Tursiops_
128
20-26
18-24
-- -- dolphin
_truncatus_
Guiana dolphin
_Sotalia_
132
26-35
26-35
-- --
_guianensis_
Rough-toothed
_Steno_
135
20-27
20-27
Crown is sometimes dolphin
_bredanensis_
marked with many
fine vertical
wrinkles.
Pygmy killer whale
_Feresa_
138
8-13
10-13
Many specimens have.
_attenuata_
fewer teeth on right
than on left side.
Many-toothed
_Peponocephala_
142
22-25
21-24
-- -- blackfish
_electra_
Pygmy sperm whale
_Kogia_
144
0
12-16
Rarely 10 or 11;
_breviceps_
curved back and
inwards; fit into
sockets in upper jaw.
Dwarf sperm whale
_Kogia simus_
148
0-3
8-11
Rarely 13; curved
back and in; sharply
pointed; fit into
sockets in upper jaw.
Rarely has 1-3 upper
teeth as well.
Harbor porpoise
_Phocoena_
150
22-28
22-28
Spade shaped, laterally
_phocoena_
compressed, and
relatively small.
[Footnote A: Usually erupted from gums only in adult [MALES].]
[Footnote B: May have toothpick size vestigial teeth in either jaw.]
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.
-----------------------------------------------------------------------------
Maximum dimensions
of plates
-------------------
Number
Width
Maximum
of
Length
base
Page of
body
baleen
----+----+----+----
Species
Species
species
size[C]
plates/
ft/
ft/
common name
scientific name
account
ft(m)
side
in.
cm
in.
cm
-------------+---------------+-------+---------+--------+----+----+----+----
Blue whale
Balaenoptera
19
85 (26.0)
270-395
33"
84
12"
30
musculus
Fin whale
Balaenoptera
26
79 (24.0)
262-473
29"
72
12"
30
physalus
Sei whale
Balaenoptera
32
62 (19.0)
318-340
31"
78
15"
39
borealis
Bryde's whale
Balaenoptera
37
46 (14.0)
250-300?
17"
42
10"
24
edeni
Humpback
Megaptera
40
53 (16.0)
270-400
24"
60
5"
13
whale
novaeangliae
Bowhead whale
Balaena
49
65 (19.8)
325-360
14'
414
14"
36
mysticetus
Right whale
Eubalaena
52
53 (16.0)
250-390
7.3'
223
12"
30
glacialis
Minke whale
Balaenoptera
63
31 (10.0)
300-325
8"
21
4"
10
acutorostrata
-----------------------------------------------------------------------------
-----------------------------------------------------------------------------
Mean No.
Numbers
of
of
Species
bristles
ventral
Relative lengths common name
Color of baleen
/cm.
grooves
of ventral grooves --------------+------------------------+--------+---------+------------------ Blue whale
All black with black
10-30
55-88
At least to navel.
bristles.
Fin whale
Dark gray to bluish
10-35
56-100
At least to navel.
gray; one-fifth to
one-third of right
front is whitish.
Sei whale
Ash black with blue
35-60
38-56
End far short of
tinge and fine, light
navel.
bristles; some near
front may be light.
Bryde's whale
Slate gray with dark
15-35
40-50
At least to navel.
bristles.
Humpback whale
Ash black to olive
10-35
14-22
At least to navel.
brown; sometimes
whitish; bristles
grayish white.
Bowhead whale
Black; anterior
?
None
XX
side of some is
present.
whitish; bristles
black.
Right whale
Dirty or yellowish gray;
35-70
None
XX
some anterior plates
present.
all or part white.
Minke whale
White to yellowish
15-25
50-70
End short of
white. Posterior plates
navel; often just
may be brown or black.
behind flippers.
[Footnote C: As stated in the Index to the species, these figures represent maximum sizes recorded for the W. N. Atlantic. For all species exploited by whaling industries' current maximum sizes will be substantially smaller than these figures (see species accounts).]
