393
Morphological descriptions of baleen have been reported since historical times
including accounts by Zorgdrager ( 1720 ), Hunter ( 1787 ), Rosenthal ( 1829 ),
Tullberg ( 1883 ), Flower ( 1883 ), Eschricht and Reinhardt ( 1866 ), Stevenson ( 1907 ),
Ruud ( 1940 ) which provided considerable detail about baleen of different whale
species. More recent descriptions of baleen have also focused on comparative size
and numbers of baleen plates in Mysticeti (Cousteau and Paccalet 1988 ), on microscopic analysis of baleen as well as its cellular and subcellular morphology (Pfeiffer
1993 ; Fudge et al. 2009a ), on growth (Sumich 2001 ), on measurement of carbon
and nitrogen isotopes in baleen in order to assess life history feeding patterns of
whales ( Hobson and Schell 1998 ), on studies examining long-term changes of metal
levels in whales (Hobson et al. 2004 ), on age estimation (Zeh et al. 2008 ), as well as
on trace element chemistry of whale baleens in an attempt to reconstruct migration
patterns (Freeburg et al. 2009 ). Studies on the isolation and sequencing of DNA
from baleens have also been carried out (Kimura and Ozawa 1997 ; Rosenbaum
et al. 1997 ). The use of whale baleen plates as a source of mitochondrial DNA
(mtDNA) presents several advantages in comparison to whale bones. First, it is relatively easy to recover mtDNA from baleen because it is not locked up in a stony
matrix, and there seems to be much more DNA in old baleen than in old bone.
Second, baleen is usually morphologically diagnostic of the species, whereas single
bone fragments often are not (Kimura and Ozawa 1997 ). Works on origin and evolution of baleen are still in progress (Meredith et al. 2010 ; Uhen 2010 ).
The structure and composition of baleen (St Aubin et al. 1984 ) as well as material properties ( Szewciw et al. 2010 ) and some biomineralization aspects of baleen
have been investigated (O’Connor 1987 ; Szewciw et al. 2010 ). Description of the
plate of baleen was given by Lauffenburger ( 1993 ) as follow:
“A plate of baleen is composed of a sandwich-like, three-part structure: a central
section of tubules in a cementing keratin matrix, fl anked by a horny covering. Inside
the whale’s mouth, the horny covering and cementing matrix are worn away by the
abrasive action of the tongue, revealing the central tubules or hairlike structures that
form the mat or sieve during fi ltration. These tubes are highly calcifi ed, containing
crystals of hydroxyapatite, and they have central hollow cavities of varying sizes
depending on the species. Calcifi cation occurs in alternating rings around the outer
edge of the tubes, an arrangement that strengthens the tubes without loss of fl exibility. Baleen is the most highly calcifi ed of the keratin materials and as a result is
slightly more brittle,” (Lauffenburger 1993 ; see also Halstead 1974 ; O’Connor
1987 ).
The biomineralogical characterization of baleen is rare. Here, only some data:
– “The sei whale ( Balaenoptera borealis ) has baleen that consists of 14.5 %
hydroxyapatite (dry weight);
– Humpback ( Megaptera novaengliae ) and minke ( Balaenoptera acutorostrata )
baleen bristles contain intermediate (up to 4 %) and low (about 1 %) calcium salt
concentrations, respectively,” (Szewciw et al. 2010 ; see also Pautard 1963 ; St
Aubin et al. 1984 ).
There is still lack on detailed information on material properties of whale baleen,
with exception of the study reported by St Aubin et al. ( 1984 ) on the effects of
11.3 Whale Baleen
Morphological descriptions of baleen have been reported since historical times
including accounts by Zorgdrager ( 1720 ), Hunter ( 1787 ), Rosenthal ( 1829 ),
Tullberg ( 1883 ), Flower ( 1883 ), Eschricht and Reinhardt ( 1866 ), Stevenson ( 1907 ),
Ruud ( 1940 ) which provided considerable detail about baleen of different whale
species. More recent descriptions of baleen have also focused on comparative size
and numbers of baleen plates in Mysticeti (Cousteau and Paccalet 1988 ), on microscopic analysis of baleen as well as its cellular and subcellular morphology (Pfeiffer
1993 ; Fudge et al. 2009a ), on growth (Sumich 2001 ), on measurement of carbon
and nitrogen isotopes in baleen in order to assess life history feeding patterns of
whales ( Hobson and Schell 1998 ), on studies examining long-term changes of metal
levels in whales (Hobson et al. 2004 ), on age estimation (Zeh et al. 2008 ), as well as
on trace element chemistry of whale baleens in an attempt to reconstruct migration
patterns (Freeburg et al. 2009 ). Studies on the isolation and sequencing of DNA
from baleens have also been carried out (Kimura and Ozawa 1997 ; Rosenbaum
et al. 1997 ). The use of whale baleen plates as a source of mitochondrial DNA
(mtDNA) presents several advantages in comparison to whale bones. First, it is relatively easy to recover mtDNA from baleen because it is not locked up in a stony
matrix, and there seems to be much more DNA in old baleen than in old bone.
Second, baleen is usually morphologically diagnostic of the species, whereas single
bone fragments often are not (Kimura and Ozawa 1997 ). Works on origin and evolution of baleen are still in progress (Meredith et al. 2010 ; Uhen 2010 ).
The structure and composition of baleen (St Aubin et al. 1984 ) as well as material properties ( Szewciw et al. 2010 ) and some biomineralization aspects of baleen
have been investigated (O’Connor 1987 ; Szewciw et al. 2010 ). Description of the
plate of baleen was given by Lauffenburger ( 1993 ) as follow:
“A plate of baleen is composed of a sandwich-like, three-part structure: a central
section of tubules in a cementing keratin matrix, fl anked by a horny covering. Inside
the whale’s mouth, the horny covering and cementing matrix are worn away by the
abrasive action of the tongue, revealing the central tubules or hairlike structures that
form the mat or sieve during fi ltration. These tubes are highly calcifi ed, containing
crystals of hydroxyapatite, and they have central hollow cavities of varying sizes
depending on the species. Calcifi cation occurs in alternating rings around the outer
edge of the tubes, an arrangement that strengthens the tubes without loss of fl exibility. Baleen is the most highly calcifi ed of the keratin materials and as a result is
slightly more brittle,” (Lauffenburger 1993 ; see also Halstead 1974 ; O’Connor
1987 ).
The biomineralogical characterization of baleen is rare. Here, only some data:
– “The sei whale ( Balaenoptera borealis ) has baleen that consists of 14.5 %
hydroxyapatite (dry weight);
– Humpback ( Megaptera novaengliae ) and minke ( Balaenoptera acutorostrata )
baleen bristles contain intermediate (up to 4 %) and low (about 1 %) calcium salt
concentrations, respectively,” (Szewciw et al. 2010 ; see also Pautard 1963 ; St
Aubin et al. 1984 ).
There is still lack on detailed information on material properties of whale baleen,
with exception of the study reported by St Aubin et al. ( 1984 ) on the effects of
11.3 Whale Baleen