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Marine Mammal Physiology: Requisites for Ocean Living
seasonally abundant (Berta and Sumich 1999). The timing of coastal migration patterns of
the California blue whale appears to be linked to annual patterns in coastal upwelling and
krill development patterns (Croll et al. 2005).
6.3.2 Pierce feeding
Another major feeding strategy among marine mammals is pierce feeding, and this is utilized by the odontocete whales (toothed whales), and most phocid and otariid seals. Pierce
feeding involves catching squid and fish using sharp, homodont teeth and swallowing
them whole, or mechanically breaking them into large pieces (Jones et al. 2013).
Species that employ pierce feeding display much greater diversity in size, habitat,
and diet than filter feeders. This more generalized diet permits greater ecological and lifehistory diversity. The range of diet types extends from deep-diving squid specialists to top
level predators. Additionally, whereas the diet of baleen whales is highly seasonal due to
the seasonal nature of zooplankton biomass and production, that of odontocetes is generally more constant year-round.
There are 7 families and 52 species that comprise the suborder Odontocete, all of
which utilize echolocation to locate their prey. Most species feed on fish and cephalopods,
with species that live on the continental shelf eating muscular fish (herring, pilchards,
whiting, and soles) and cephalopods (squid, cuttlefish, and octopods), and species that live
in deeper oceanic waters eating mainly fish of the Myctophidae family, and soft-bodied,
gelatinous squids. In contrast to mystecetes, most odontocete species generally chase, capture, and swallow single relatively large prey items (fish, squid, large crustaceans, and
occasionally other marine mammals).
Broadly speaking, for dolphins (family Delphinidae) cephalopods comprise over 75%
of the diet and fish make up the remainder. Depending on the species, cephalopod prey
taken can be muscular squid for species living on the continental shelf, including the shortbeaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops
truncatus). The diet of other species, including the spinner dolphin (Stenella longirostris) and
spotted dolphins (Stenella attenuata and Stenella frontalis), may include many soft-bodied
oceanic species. Overall, dolphins, including species found in oceanic waters (including
pilot whales, Globicephala spp.), favor muscular squid over soft-bodied species. Other species, such as Commerson’s dolphins (Cephalorhynchus commersonii), eat some krill and killer
whales also prey on seals and other crustaceans.
For the porpoises (family Phocoenidae), cephalopods are also the primary prey (75% of
the diet) together with fish for half of the species in this family. Cephalopods comprise 50%–
75% and fish comprise 25%–50% of the diet in the other half of the species. Porpoises are
a family of inshore cetaceans, and their food consists of common muscular inshore squid,
cuttlefish, and octopus, as well as fish such as herrings, whitings, and bottom-living soles.
Many aspects of the diet of beaked whales are poorly understood, but in general, more
than half of the food of beaked whales (family Ziphidae) consists of cephalopods and the
rest is fish. These whales are deep divers and at least one species favors soft-bodied squids.
The number of teeth in this family is highly reduced and the two teeth in the lower jaw
grow over the upper jaw and limit it to a narrow gape. In most species of beaked whales,
females and juveniles lack erupted teeth and that of adult males are primarily used for
intraspecific fighting (Heyning and Mead 1996). It has been hypothesized that some species may capture prey primarily by suction (Caldwell et al. 1966; Norris and Mohl 1983),
and observations of live animals corroborate the anatomical findings that beaked whales
use suction to acquire prey (Heyning and Mead 1996).
Marine Mammal Physiology: Requisites for Ocean Living
seasonally abundant (Berta and Sumich 1999). The timing of coastal migration patterns of
the California blue whale appears to be linked to annual patterns in coastal upwelling and
krill development patterns (Croll et al. 2005).
6.3.2 Pierce feeding
Another major feeding strategy among marine mammals is pierce feeding, and this is utilized by the odontocete whales (toothed whales), and most phocid and otariid seals. Pierce
feeding involves catching squid and fish using sharp, homodont teeth and swallowing
them whole, or mechanically breaking them into large pieces (Jones et al. 2013).
Species that employ pierce feeding display much greater diversity in size, habitat,
and diet than filter feeders. This more generalized diet permits greater ecological and lifehistory diversity. The range of diet types extends from deep-diving squid specialists to top
level predators. Additionally, whereas the diet of baleen whales is highly seasonal due to
the seasonal nature of zooplankton biomass and production, that of odontocetes is generally more constant year-round.
There are 7 families and 52 species that comprise the suborder Odontocete, all of
which utilize echolocation to locate their prey. Most species feed on fish and cephalopods,
with species that live on the continental shelf eating muscular fish (herring, pilchards,
whiting, and soles) and cephalopods (squid, cuttlefish, and octopods), and species that live
in deeper oceanic waters eating mainly fish of the Myctophidae family, and soft-bodied,
gelatinous squids. In contrast to mystecetes, most odontocete species generally chase, capture, and swallow single relatively large prey items (fish, squid, large crustaceans, and
occasionally other marine mammals).
Broadly speaking, for dolphins (family Delphinidae) cephalopods comprise over 75%
of the diet and fish make up the remainder. Depending on the species, cephalopod prey
taken can be muscular squid for species living on the continental shelf, including the shortbeaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops
truncatus). The diet of other species, including the spinner dolphin (Stenella longirostris) and
spotted dolphins (Stenella attenuata and Stenella frontalis), may include many soft-bodied
oceanic species. Overall, dolphins, including species found in oceanic waters (including
pilot whales, Globicephala spp.), favor muscular squid over soft-bodied species. Other species, such as Commerson’s dolphins (Cephalorhynchus commersonii), eat some krill and killer
whales also prey on seals and other crustaceans.
For the porpoises (family Phocoenidae), cephalopods are also the primary prey (75% of
the diet) together with fish for half of the species in this family. Cephalopods comprise 50%–
75% and fish comprise 25%–50% of the diet in the other half of the species. Porpoises are
a family of inshore cetaceans, and their food consists of common muscular inshore squid,
cuttlefish, and octopus, as well as fish such as herrings, whitings, and bottom-living soles.
Many aspects of the diet of beaked whales are poorly understood, but in general, more
than half of the food of beaked whales (family Ziphidae) consists of cephalopods and the
rest is fish. These whales are deep divers and at least one species favors soft-bodied squids.
The number of teeth in this family is highly reduced and the two teeth in the lower jaw
grow over the upper jaw and limit it to a narrow gape. In most species of beaked whales,
females and juveniles lack erupted teeth and that of adult males are primarily used for
intraspecific fighting (Heyning and Mead 1996). It has been hypothesized that some species may capture prey primarily by suction (Caldwell et al. 1966; Norris and Mohl 1983),
and observations of live animals corroborate the anatomical findings that beaked whales
use suction to acquire prey (Heyning and Mead 1996).