Whales, Dolphins, and Porpoises of the Western North Atlantic Part 19

Females and subadult males may be confused with any of the beaked whales species (p. 74 and Fig. 78).

[Ill.u.s.tration: Figure 79.--Two views of the body of a stranded True's beaked whale from northeastern Florida. This species reaches at least 16 feet (4.9 m) and closely resembles the goosebeaked whale in general body shape. It is distributed in temperate waters from Nova Scotia to Florida. (_Photos courtesy of Marineland of Florida._)]

[Ill.u.s.tration: Figure 80.--The head of a True's beaked whale stranded in North Carolina. Note the small head, the p.r.o.nounced beak, and the position of the blowhole in the indentation behind the forehead. The teeth, visible above the gums only in adult males, are in the position indicated by the arrow. The photo on the right shows the two V-shaped throat grooves characteristic of beaked whales. (_Photos from U.S.

National Museum, courtesy of J. G. Mead._)]

ANTILLEAN BEAKED WHALE (T)

_Mesoplodon europaeus_ (Gervais 1855) (equals _M. gervaisi_ [Deslongchamps])

Other Common Names

Gulfstream beaked whale, Gervais' beaked whale.

Description

Antillean beaked whales reach a length of at least 22 feet (6.7 m). They are slender in form and appear somewhat laterally compressed (i.e., taller than they are wide). The head is extremely small and tapers rapidly to a narrow beak. The flippers are small (to about one-twelfth the body length) with their origin well down on the sides of the body.

The dorsal fin is small, located behind the midpoint of the back, and variable in shape from falcate to triangular. The flukes are less than one-fifth the body length and are not notched.

Antillean beaked whales are dark grayish black on the back and sides, slightly lighter on the abdomen. The flukes are dark gray above and below.

Natural History Notes

Antillean beaked whales are probably primarily oceanic in distribution and are known to feed on squid.

May Be Confused With

Antillean beaked whales may be confused with any of the other beaked whales though they are larger than all except the northern bottlenosed whale (p. 67) and the goosebeaked whale (p. 70).

Distribution

Antillean beaked whales have been reported stranded from the lat.i.tude of Long Island, N.Y. south to Florida, thence into the Caribbean and the Gulf of Mexico.

Stranded Specimens

The teeth of Antillean beaked whales are located at the suture of the mandible, about one-third of the way from the tip of the snout to the corner of the mouth (Fig. 78).

[Ill.u.s.tration: Figure 81.--Two views of an Antillean beaked whale stranded in New Jersey in 1899. Note the very small head, the prominent back-curved dorsal fin, and the slightly concave rear margin of the tail flukes, which lack a distinct notch. (_Photos by F. W. True, courtesy of U.S. National Museum._)]

[Ill.u.s.tration: Figure 82.--Two views of an Antillean beaked whale stranded in Jamaica. This species reached at least 22 feet (6.7 m) in length. Compared to the smaller True's beaked whale, Antillean beaked whales have a smaller head, a narrower beak, and a taller, narrower body. Furthermore, the teeth of this species are located about one-third of the way back from the tip of the snout to the corner of the mouth.

(_Photos by J. J. Rankin._)]

DENSE-BEAKED WHALE (T)

_Mesoplodon densirostris_ (Blainville in Desmarest 1817)

Other Common Names

None known.

Description

Dense-beaked whales reach a length of at least 17 feet (5.2 m). The body is distinctly spindle-shaped. The head, the contour of which is the most distinctive characteristic of this species, is marked by a prominent rise, located near the angle of the gape on each side. This rise, which bears the teeth, gives a peculiar high, arching contour to the mouth (p.

84), particularly in adult males.

The flippers are small (one-eleventh to one-tenth the body length) and have their origin in the lighter color of the lower sides. The dorsal fin varies from small and triangular to nearly falcate and pointed on the tip. It is located behind the midpoint of the back. The flukes are from one-sixth to one-fifth the body length, are seldom notched, and occasionally even bulge slightly backwards near the center of the rear margin.

Dense-beaked whales are black or charcoal gray on the back, slightly lighter on the abdomen. They are somewhat blotched with grayish white and are often extensively scratched or scarred. The flippers are lighter than the back. The flukes are dark above, light below.

Natural History Notes

From stomach contents of stranded animals dense-beaked whales are known to feed on squid.

May Be Confused With

Adult male dense-beaked whales can be separated from the other beaked whales by the high, arching contour to the corners of the mouth. If there is no adult male in the group, however, dense-beaked whales may be confused with any of the other beaked whales species.

Distribution

Dense-beaked whales have been reported from Peggys Cove, Nova Scotia south to Florida. From all accounts, this species appears widely but spa.r.s.ely distributed in warm temperate seas.

Stranded Specimens

Adults of this species should be distinguishable by the highly distinctive contour of the mouth. The teeth, located in the high rise of the mouth, are oriented slightly backwards.

[Ill.u.s.tration: Figure 83.--A dense-beaked whale in the tank at New York Aquarium. Note the position of the prominent dorsal fin, just breaking the surface. The blow of beaked whales is usually small and inconspicuous and reportedly projects markedly forward from the head.

(_Photo by J. G. Mead._)]

[Ill.u.s.tration: Figure 84.--Views of the heads of dense-beaked whales.

Females (bottom) and immature males have a slight curvature to the rear of the mouth. As they mature, males (middle and top) begin to display the two arching prominences near the corners of the mouth which give the characteristic contour to the mouth. The teeth are located in these prominences and are oriented slightly backwards. (Photos from _northeastern Florida by W. A. Huck, courtesy of Marineland of Florida_ (top and middle) and by J. G. Mead (bottom).)]