Ziphius cavirostris Cuvier, 1823

Adult females seen with juvenile (23 Apr 2009) and a calf (20 May 2012).

Dinis, A., R. W. Baird, et al. (2017). "Beaked whales with rostrum deformities: Implications for survival and reproduction." Marine Mammal Science ****(****): ***** [9 pp.]. Beaked whales, members of the family Ziphiidae, are thought to be suction feeders (Heyning and Mead 1996).With the exception of the Shepherd's beaked whale (Tasmacetus shepherdi), all beaked whales have a reduction in the number of erupted teeth. In their upper jaws, teeth are absent or vestigial; only one or two pairs of teeth are found in the lower jaws, and usually erupt only in adult males, where they are thought to function primarily for combat between males (Mead 2002). Beaked whales also have two throat grooves that allow them to stretch and expand their throat, and a mobile tongue that can be retracted quickly, creating a drop in pressure that would suck prey into their mouths (Heyning and Mead 1996). Most of the information on diet of beaked whales comes from analyses of stomach contents of stranded individuals (MacLeod et al. 2003). They are believed to feed mainly on cephalopods (e.g., Lefkaditou and Poulopoulos 1998, Blanco and Raga 2000, Santos et al. 2001, MacLeod et al. 2003), although fish and crustaceans also play an important role in the diet of these whales, especially in some Mesoplodon species (Debrot and Barros 1994, Santos et al. 2007, Wenzel et al. 2013). With such a specific diet and feeding strategy, the rostral anatomy of beaked whales is considered a key aspect in feeding success. Here we report on several beaked whales with rostral malformations, including information on their sighting histories, suggesting that even with major deformities of the rostrum, beaked whales appear to be able to feed and reproduce successfully.

24 Jul 2019

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