Identifying the Animal
Cetaceans may be found during or shortly after the stranding or many months later, when the carcass is bloated or rotted nearly beyond recognition. If the stranded animal is alive or freshly dead, it can be identified by any of the characteristics itemized in the text. But even if it is in an advanced stage of decomposition it can be identified using the key below. In general numbers and descriptions of teeth ([Table 1]) and numbers and descriptions of baleen plates ([Table 2]) persist longest as reliable identifying characteristics. If they are still detectable on the carcass, numbers and lengths of ventral grooves may also be used to separate the balaenopterine whales.[17]
[17] The tables were prepared primarily from Tomilin (1967) and supplemented by miscellaneous published papers and our own observations. The sections on toothed whales in the key were developed following the general outline of Moore (1953).
In order to use the key below, begin with the first pair of opposing characteristics—one of the two will apply to the specimen you are examining. On the line following that statement there will be a paragraph number, go to that paragraph. There you will find two more paired, opposing characteristics. Again, one of the two will apply to the specimen you are examining. Select that one and go to the paragraph indicated on the line following it. Continue this procedure until the statement which is true for your specimen is followed by a species name instead of a reference to another paragraph. This name identifies the specimen. To verify your identification go to the discussion of that species in the text. With a little practice and careful attention to details, identification of whales, dolphins, and porpoises will become easier.
KEY TO THE IDENTIFICATION OF STRANDED CETACEANS OF THE WESTERN NORTH ATLANTIC
- 1. a. Double blowhole; no teeth present in either jaw; baleen plates in upper jaws.
- (Baleen whale) Go to 2
- b. Single blowhole; teeth present (sometimes concealed beneath the gums); no baleen plates in upper jaw.
- (Toothed whale) Go to 9
- 2. a. Ventral grooves present; dorsal fin present; viewed in profile, upper jaw relatively flat and broad.
- (Balaenopterine whale) Go to 3
- b. Ventral grooves absent; dorsal fin absent; viewed in profile, upper jaw and lower lips strongly arched; upper jaw very narrow.
- (Right whale) Go to 8
- 3. a. Ventral grooves end before navel.[18]
- Go to 4
- b. Ventral grooves extend to or beyond navel
- Go to 5
- 4. a. 50-70 ventral grooves, longest often ending between flippers; baleen less than 8 inches (20.3 cm), mostly white or yellowish white (some posterior plates may be dark) with 15-25 white bristles per centimeter; 300-325 plates per side.
- Minke whale, p. [63]
- b. 38-56 ventral grooves, longest ending well short of navel; baleen less than 31 inches (78.7 cm), black (some anteriormost plates may be white) and with 35-60 fine silky white bristles per centimeter; 318-340 plates per side.
- Sei whale, p. [32]
- 5. a. Flippers one-fourth to one-third length of the body length and knobbed on leading edge; less than 22 broad and conspicuous ventral grooves, longest extending at least to navel; head covered with numerous knobs; baleen less than 24 inches (61 cm), ash black to olive brown (sometimes whitish) with 10-35 grayish white bristles per centimeter; 270-400 plates per side.
- Humpback whale, p. [40]
- b. Flippers less than one-fifth body length; no knobs; from 40 to 100 fine ventral grooves, longest extending at least to navel; head lacks knobs
- Go to 6
- 6. a. Three ridges on head, one from blowholes, forward towards tip of snout, one auxiliary groove along each side of main ridge; 40-50 ventral grooves; 250-300 slate-gray baleen plates with 15-35 dirty gray bristles per centimeter.
- Bryde's whale, p. [37]
- b. Only one prominent ridge on head,[19] from just in front of blowholes forward towards tip of snout; 55-100 ventral grooves
- Go to 7
- 7. a. Head broad and U-shaped; dorsal fin less than 13 inches (33 cm) and very far back on tail stock; baleen all black with 10-30 black bristles per centimeter; plates extremely broad relative to length.
- Blue whale, p. [19]
- b. Head broad at gape but sharply pointed on tip; dorsal fin to 24 inches (61 cm) and slightly more than one-third forward from tail; right front one-fifth to one-third of baleen ivory white to yellowish white, remainder dark gray to bluish gray streaked with yellowish white; plates have 10-35 gray or white bristles per centimeter and are narrow relative to length.
- Fin whale, p. [26]
- 8. a. Top of snout not covered with callosities; 325-360 baleen plates per side, longest reaching 14 feet (4.3 m); plates black with black bristles (anterior portion of some plates may be whitish).
- Bowhead whale, p. [49]
- b. Top of snout covered with callosities, often including lice and/or barnacles; 250-390 baleen plates per side, longest reaching 7.2 feet (2.2 m); plates dirty or yellowish gray (some anterior plates all or part white and some posterior plates brown or black) with 35-70 bristles per centimeter.
- Right whale, p. [52]
- 9. a. Upper part of head extending appreciably past tip of lower jaw; lower jaw markedly undershot and considerably narrower than upper jaw
- Go to 10
- b. Upper part of head not extending appreciably past tip of lower jaw; lower jaw approximately same width as upper jaw
- Go to 12
- 10. a. Body more than 13 feet (4.0 m); head massive, to one-third of body length; blowhole located far forward of eyes and to left front of head; dorsal fin low, triangular or rounded followed by series of knuckles or crenulations; 18-25 teeth in each lower jaw fit into sockets in upper jaw (10-16 upper teeth rarely emerge).
- Sperm whale, p. [57]
- b. Body less than 13 feet (4.0 m); head considerably less than one-third body length; blowhole located approximately even with eyes on top of head, slightly displaced to left but not on left front of head; conspicuous dorsal fin present; 8-16 teeth in each lower jaw fitting into sockets in upper jaw
- Go to 11
- 11. a. No creases on throat; dorsal fin small and located in latter third of back; 12-16 teeth (rarely 10-11) in each lower jaw.
- Pygmy sperm whale, p. [144]
- b. Inconspicuous creases on throat; dorsal fin tall and falcate, resembling that of the Atlantic bottlenosed dolphin, and located near middle of back; 8-11 (rarely 13) extremely sharp teeth in each lower jaw; rarely 1-3 teeth in each upper jaw.
- Dwarf sperm whale, p. [148]
- 12. a. Two conspicuous grooves on outer surface of throat forming V-shape pointed forward; notch absent or inconspicuous in flukes.
- (Beaked whale) Go to 13
- b. No conspicuous grooves on outer surface of throat; deep median notch on rear margin of tail flukes
- Go to 18
- 13. a. A pair of teeth located at the tip of the lower jaw (erupted only in adult males, concealed in females and immature animals)
- Go to 14
- b. No teeth at the tip of the lower jaw
- Go to 16
NOTE: Immature individuals of the species covered in paragraphs 14 and 15 may not be readily identifiable without museum preparation and examination.