OTHER BEAKED WHALES (T) 



Mesoplodon spp. 



Other Common Names 



Grampus (St. Vincent) (see also p. 96). 



Description 



In addition to the northern bottlenosed whale (p. 67) and 

 the goosebeaked whale (p. 70), four other species of beaked 

 whales have been reported from the western North Atlantic. 

 All four species are known primarily from stranded 

 specimens and have been rarely encountered at sea. 

 Therefore statements of range are usually limited to 

 inferences from locations of strandings, and information on 

 appearance and habits of the species in the wild is almost 

 totally lacking. 



The infrequent encounters with beaked whales at sea may 

 result from such factors as 1) a low inconspicuous blow, 2) 

 avoidance of ships, and/or 3) distribution in small groups in 

 offshore areas well outside the normal boating lanes. 



The following descriptions will aid primarily in identifying 



stranded specimens. Though subtle differences in ranges, 

 color patterns, and dorsal fin shapes and positions may be 

 helpful in narrowing the choices of living animals, the species 

 will continue to be extremely difficult to distinguish from one 

 another in the brief encounters typical at sea until additional 

 data are collected. 



The beaked whales have the following characteristics in 

 common: 1) two small creases forming a V-shape on the throat 

 2) the absence of a conspicuous notch on the rear margin of the 

 tail flukes (some specimens have a slight indentation), and 31 

 the absence of functional teeth in all except adult males. 

 Adult males have a single pair of teeth in the lower jaw, the 

 position and description of which help to identify the species. 

 The teeth of females are not functional and only rarely 

 emerge from the gums. Therefore, if a stranded animal is an 

 adult male, its species can be determined by the position and 

 description of the teeth. For example, in Mesoplodon mirus, 

 the teeth are located near the tip of the lower jaw; in M. 

 europaeus, they are located about a third of the way from the 

 tip of the snout to the corner of the mouth; in M. bidens, they 



Figure 76. - An unidentified beaked whale from the mid-Pacific. Note the marks along the back, presumably tooth rakes, consisting of scratches that are 

 paired and close together. A beaked whale in the western North Atlantic marked in this manner would be a northern bottlenosed whale (p. 671, a goose- 

 beaked whale (p. 70), or a True's beaked whale (p. 77). These are the only three species in which the teeth are located close together near the tip of the 

 lower jaw. {Photo by K. C. Balcomb.) 



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