xix
Introduction
Christopher D. Marshall and Jeremy A. Goldbogen (Chapter 5) begin Section II by
examining the feeding mechanisms that have been developed by marine species. How
do dugongs and manatees digest their vegetarian diet? Are the teeth of marine mammals
any different than terrestrial species? How do baleen whales obtain their food compared
to polar bears?
Mark A. Hindell and Andrea Walters (Chapter 6) continue with questions on diet and
nutrition. They examine the ranges of diets in many species, looking at common dietary
characteristics. Many whale species filter feed, but this is primarily in polar and highproductivity regions in the ocean. Did you know that some seals also filter feed? Marine
mammals are incredibly diverse in their diets, ranging from tiny krill and copepods, all
the way to the 6 ft Antarctic cod and, in some cases, other marine mammals.
It is well known that humans cannot survive on the ocean without access to freshwater. Miwa Suzuki and Rudy M. Ortiz (Chapter 7) explore the fascinating question of water
balance in marine species. You will discover that marine mammal kidneys look very different from those of a terrestrial mammal, yet have many physiological and biochemical
similarities. If available, will a marine mammal drink freshwater or ignore it?
Many marine mammals fast for very long periods either during migration or when on
land for breeding purposes. While Suzuki and Ortiz (Chapter 7) looked at this from water
balance requirements, David Rosen and Allyson Hindle (Chapter 8) ask how some marine
mammals can live for months with little or no access to food? They explore the sources of
energy during these periods on a biochemical and physiological basis.
Finally, Michael A. Castellini and Jo-Ann Mellish (Chapter 9) address how marine
mammals stay warm in a cold sea, yet do not overheat when on land. They look at the
normal body temperature of a marine mammal, and how their fur or blubber helps to
maintain that temperature. What about species that live on the frozen sea ice and give
birth to pups at extremely cold temperatures? Will some of the predicted changes in water
temperature through climate change impact marine mammals?
In the next section of the book (Section III), the authors focus on the amazing physiology of giving birth, and how these mammals have adapted to support their calves/pups
in a marine environment. Daniel E. Crocker and Birgitte I. McDonald (Chapter 10) take
you onto elephant seal breeding beaches where nursing mothers support rapidly growing
newborn pups, yet do not eat or drink for many weeks. They explore the complex biochemical pathways that allow milk production during caloric restriction. They address the
support of newborn whale calves and overwintering polar bears alike.
Sensory systems must clearly be very different in marine versus terrestrial mammals,
as they have to be able to hear and see underwater with very high resolution. Do they have
other senses that we only partially understand?
Dorian Houser and Jason Mulsow (Chapter 11) begin with a focus on the acoustic
aspects of the physiology and anatomy of hearing underwater. It is well known that
marine mammals can produce a large range of acoustic calls, many of which are not in
the audible range of humans. What is the nature of their sound production? What are the
differences in the acoustic biology of whales and sea otters? Increasing background noise
in the ocean, and how that may influence marine mammals, is another point of discussion
in this chapter.
Marine mammals must be able to see both in the air at the surface and deep underwater. The darkness of the ocean at several hundred meters and variable light under the
sea ice are not conditions that we as humans are built to contend with. Frederike D. Hanke
and Guido Dehnhardt (Chapter 12) consider the difference in the neural structures of the
vision system across marine mammals. They look at how they might sense particle flow
Introduction
Christopher D. Marshall and Jeremy A. Goldbogen (Chapter 5) begin Section II by
examining the feeding mechanisms that have been developed by marine species. How
do dugongs and manatees digest their vegetarian diet? Are the teeth of marine mammals
any different than terrestrial species? How do baleen whales obtain their food compared
to polar bears?
Mark A. Hindell and Andrea Walters (Chapter 6) continue with questions on diet and
nutrition. They examine the ranges of diets in many species, looking at common dietary
characteristics. Many whale species filter feed, but this is primarily in polar and highproductivity regions in the ocean. Did you know that some seals also filter feed? Marine
mammals are incredibly diverse in their diets, ranging from tiny krill and copepods, all
the way to the 6 ft Antarctic cod and, in some cases, other marine mammals.
It is well known that humans cannot survive on the ocean without access to freshwater. Miwa Suzuki and Rudy M. Ortiz (Chapter 7) explore the fascinating question of water
balance in marine species. You will discover that marine mammal kidneys look very different from those of a terrestrial mammal, yet have many physiological and biochemical
similarities. If available, will a marine mammal drink freshwater or ignore it?
Many marine mammals fast for very long periods either during migration or when on
land for breeding purposes. While Suzuki and Ortiz (Chapter 7) looked at this from water
balance requirements, David Rosen and Allyson Hindle (Chapter 8) ask how some marine
mammals can live for months with little or no access to food? They explore the sources of
energy during these periods on a biochemical and physiological basis.
Finally, Michael A. Castellini and Jo-Ann Mellish (Chapter 9) address how marine
mammals stay warm in a cold sea, yet do not overheat when on land. They look at the
normal body temperature of a marine mammal, and how their fur or blubber helps to
maintain that temperature. What about species that live on the frozen sea ice and give
birth to pups at extremely cold temperatures? Will some of the predicted changes in water
temperature through climate change impact marine mammals?
In the next section of the book (Section III), the authors focus on the amazing physiology of giving birth, and how these mammals have adapted to support their calves/pups
in a marine environment. Daniel E. Crocker and Birgitte I. McDonald (Chapter 10) take
you onto elephant seal breeding beaches where nursing mothers support rapidly growing
newborn pups, yet do not eat or drink for many weeks. They explore the complex biochemical pathways that allow milk production during caloric restriction. They address the
support of newborn whale calves and overwintering polar bears alike.
Sensory systems must clearly be very different in marine versus terrestrial mammals,
as they have to be able to hear and see underwater with very high resolution. Do they have
other senses that we only partially understand?
Dorian Houser and Jason Mulsow (Chapter 11) begin with a focus on the acoustic
aspects of the physiology and anatomy of hearing underwater. It is well known that
marine mammals can produce a large range of acoustic calls, many of which are not in
the audible range of humans. What is the nature of their sound production? What are the
differences in the acoustic biology of whales and sea otters? Increasing background noise
in the ocean, and how that may influence marine mammals, is another point of discussion
in this chapter.
Marine mammals must be able to see both in the air at the surface and deep underwater. The darkness of the ocean at several hundred meters and variable light under the
sea ice are not conditions that we as humans are built to contend with. Frederike D. Hanke
and Guido Dehnhardt (Chapter 12) consider the difference in the neural structures of the
vision system across marine mammals. They look at how they might sense particle flow