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Chapter ten: Post-partum
An average elephant seal pup assimilates energy at a rate of 8.3× BMR during suckling (Crocker et al. 2001) and a hooded seal pup is likely the highest rate of nutritional assimilation relative to body weight found in nature. These feats require an
appropriate lipid digestion and intestinal uptake capacity, mechanisms to transport
the digested lipids to adipose tissue for storage, and the ability to withstand extreme
blood lipemia, or high concentrations of emulsified fat. The digestive adaptations of
pinnipeds have yet to be studied.
Glossary
Adipocyte triglyceride lipase (ATGL): An enzyme that removes the first fatty acid from
a triaglycerol molecule. This enzyme has been shown to be the predominant lipolytic enzyme in some marine mammal’s blubber.
Adiposity: The degree of fatness of an animal. High adiposity is a feature of most marine
mammals.
Altricial: A young animal born in an undeveloped state with limited mobility and requiring a high level of care and feeding by the parents compared to precocial young.
Capital breeding: A breeding strategy in which all or most of the energy used for breeding comes from stored body reserves. Capital and income breeding are two
extremes on a continuous scale.
Doubly labeled water: Isotopically labeled water, in which both the oxygen and hydrogen molecules have been labeled with isotopes. The doubly labeled water method
uses turnover of the tracer to measure CO 2 production and is an important technique for measuring the field metabolic rates of free-ranging animals.
Fecundity: The ability to produce offspring. Fecundity is usually defined as the rate of
births for an individual or species.
Income breeding: A breeding strategy in which animals foraging during the period of
reproduction. Capital and income breeding are two extremes on a continuous
scale.
Involution: The shrinkage of an organ to its former size when inactive. Involution is
usually used in reference to reproductive organs or mammary glands after
reproduction.
Isotope dilution method: A technique using the dilution of isotopically labeled compounds to measure the quantity of the compound in an animal. This method most
frequently refers to the use of isotopic labeled water to measure total body water,
body composition, or milk intake.
Lipolysis: The breakdown of fats and other lipids by hydrolysis to release fatty acids.
Lipolysis is the key process in mobilizing energy for fasting marine mammals.
Metabolic overhead: The proportion of a lactating female’s energy expenditure that goes
to her own maintenance metabolism instead of milk energy delivery to the pup
or calf.
Metabolic water production: The water that is produced as a result of cellular respiration.
For many marine mammals this is the only source of water for milk production
and survival during fasting.
Perinatal period: The period immediately after birth. In otariids, this period refers to the
initial period of lactation before the mother returns to sea to forage.
Photogrammetry: The use of photographs to make measurements of animals usually estimates of mass or surface area. This technique allows measurements to be made of
animals without handling them.
Chapter ten: Post-partum
An average elephant seal pup assimilates energy at a rate of 8.3× BMR during suckling (Crocker et al. 2001) and a hooded seal pup is likely the highest rate of nutritional assimilation relative to body weight found in nature. These feats require an
appropriate lipid digestion and intestinal uptake capacity, mechanisms to transport
the digested lipids to adipose tissue for storage, and the ability to withstand extreme
blood lipemia, or high concentrations of emulsified fat. The digestive adaptations of
pinnipeds have yet to be studied.
Glossary
Adipocyte triglyceride lipase (ATGL): An enzyme that removes the first fatty acid from
a triaglycerol molecule. This enzyme has been shown to be the predominant lipolytic enzyme in some marine mammal’s blubber.
Adiposity: The degree of fatness of an animal. High adiposity is a feature of most marine
mammals.
Altricial: A young animal born in an undeveloped state with limited mobility and requiring a high level of care and feeding by the parents compared to precocial young.
Capital breeding: A breeding strategy in which all or most of the energy used for breeding comes from stored body reserves. Capital and income breeding are two
extremes on a continuous scale.
Doubly labeled water: Isotopically labeled water, in which both the oxygen and hydrogen molecules have been labeled with isotopes. The doubly labeled water method
uses turnover of the tracer to measure CO 2 production and is an important technique for measuring the field metabolic rates of free-ranging animals.
Fecundity: The ability to produce offspring. Fecundity is usually defined as the rate of
births for an individual or species.
Income breeding: A breeding strategy in which animals foraging during the period of
reproduction. Capital and income breeding are two extremes on a continuous
scale.
Involution: The shrinkage of an organ to its former size when inactive. Involution is
usually used in reference to reproductive organs or mammary glands after
reproduction.
Isotope dilution method: A technique using the dilution of isotopically labeled compounds to measure the quantity of the compound in an animal. This method most
frequently refers to the use of isotopic labeled water to measure total body water,
body composition, or milk intake.
Lipolysis: The breakdown of fats and other lipids by hydrolysis to release fatty acids.
Lipolysis is the key process in mobilizing energy for fasting marine mammals.
Metabolic overhead: The proportion of a lactating female’s energy expenditure that goes
to her own maintenance metabolism instead of milk energy delivery to the pup
or calf.
Metabolic water production: The water that is produced as a result of cellular respiration.
For many marine mammals this is the only source of water for milk production
and survival during fasting.
Perinatal period: The period immediately after birth. In otariids, this period refers to the
initial period of lactation before the mother returns to sea to forage.
Photogrammetry: The use of photographs to make measurements of animals usually estimates of mass or surface area. This technique allows measurements to be made of
animals without handling them.