163
It was suggested (Wyeth 2010 ) that marine birds tracking odor plumes to fi nd prey,
burrows, or islands in conditions with variable wind direction could potentially switch
to a magnetic compass as the next best sensory option, when visual cues for orientation are limited. Importantly, detecting this navigational strategy depends on testing
the animals in a situation with unreliable primary cue(s) that will invoke the switch
to a magnetic compass sense. Previous tests have not supported a role for magnetoreception in the wandering albatross’ navigation (Bonadonna et al. 2005 ) without
focusing observations during periods of wind heading variation (if they occur).
Thus, any differences in navigational behaviors affected by the magnetic manipulations may have been overwhelmed by data collected in periods of steady wind, when
a magnetic compass sense may not be used in navigation. Consideration of this
hypothesis for any particular animal should begin with measurements of locomotory
patterns, the location of navigational targets, and the sensory cues animals use to detect
those targets. If situations arise where the animals appear to be abandoning the primary cues and switching to another cue prior to reaching a stationary navigational
goal, then magnetic and control manipulations in those situations can test whether a
magnetic compass sense plays a role in short distance navigation (Wyeth 2010 ).
3.5.4 Magnetite in Cetaceans
The idea to fi nd and to extract the probably very large example of biomagnetite
from whales, is defi nitively intriguing. However, to date there are no reports on any
fi ndings. Although the interest in studies on magnetoreception in mammals is high
(Nemec et al. 2001 ), there are only few publications on magnetic senses in these
marine mammals. Thus, it was reported about identifi cation of some magnetite-like
materials within brains of a Cuvier’s beaked whale ( Ziphius cavirostris ) (Cranford
et al. 2008 ), bottlenose dolphin ( Tursiops truncates ), Dall’s purpoise ( Phocoenoides
dalli ), and the humpback whale ( Megaptera novaeangliae ) (Bauer et al. 1986 ). In
her work that was extended by Kirschvink and co-workers (Kirschvink et al. 1985a ,
b ; Kirschvink 1990 ) on magnetic sense in cetaceans, Klinowska ( 1985 ) suggested
as follow: “healthy whales that strand themselves alive must have made a serious
navigational mistake and that analyzing the circumstances surrounding such strandings might identify the sensory modality responsible for the error,” (Walker et al.
1992 ). Klinowska found correlation between stranding positions of the animals and
areas where magnetic minima intersect the coast of Great Britain. Similar experiments have been carried out by Kirschvink and his colleagues on the east coast of
the United States. These researchers developed methods that demonstrated statistically reliable correlations of whale’s stranding sites with locations where magnetic
minima intersected the coast (Weisburd 1984 ). Result: “total intensity variations of
as little as 50 nano Tesla (nT; 0.1 % of the total fi eld) were suffi cient to infl uence
stranding location” (Walker et al. 1992 ; see also Kirschvink 1990 ; Kirschvink et al.
1985a , b , 1986 ). These results confi rm the hypothesis that mysticete species “possess
magnetic sense that they use to guide migration” (Walker et al. 1992 ).
3.5 Biomagnetite in Marine Vertebrates
It was suggested (Wyeth 2010 ) that marine birds tracking odor plumes to fi nd prey,
burrows, or islands in conditions with variable wind direction could potentially switch
to a magnetic compass as the next best sensory option, when visual cues for orientation are limited. Importantly, detecting this navigational strategy depends on testing
the animals in a situation with unreliable primary cue(s) that will invoke the switch
to a magnetic compass sense. Previous tests have not supported a role for magnetoreception in the wandering albatross’ navigation (Bonadonna et al. 2005 ) without
focusing observations during periods of wind heading variation (if they occur).
Thus, any differences in navigational behaviors affected by the magnetic manipulations may have been overwhelmed by data collected in periods of steady wind, when
a magnetic compass sense may not be used in navigation. Consideration of this
hypothesis for any particular animal should begin with measurements of locomotory
patterns, the location of navigational targets, and the sensory cues animals use to detect
those targets. If situations arise where the animals appear to be abandoning the primary cues and switching to another cue prior to reaching a stationary navigational
goal, then magnetic and control manipulations in those situations can test whether a
magnetic compass sense plays a role in short distance navigation (Wyeth 2010 ).
3.5.4 Magnetite in Cetaceans
The idea to fi nd and to extract the probably very large example of biomagnetite
from whales, is defi nitively intriguing. However, to date there are no reports on any
fi ndings. Although the interest in studies on magnetoreception in mammals is high
(Nemec et al. 2001 ), there are only few publications on magnetic senses in these
marine mammals. Thus, it was reported about identifi cation of some magnetite-like
materials within brains of a Cuvier’s beaked whale ( Ziphius cavirostris ) (Cranford
et al. 2008 ), bottlenose dolphin ( Tursiops truncates ), Dall’s purpoise ( Phocoenoides
dalli ), and the humpback whale ( Megaptera novaeangliae ) (Bauer et al. 1986 ). In
her work that was extended by Kirschvink and co-workers (Kirschvink et al. 1985a ,
b ; Kirschvink 1990 ) on magnetic sense in cetaceans, Klinowska ( 1985 ) suggested
as follow: “healthy whales that strand themselves alive must have made a serious
navigational mistake and that analyzing the circumstances surrounding such strandings might identify the sensory modality responsible for the error,” (Walker et al.
1992 ). Klinowska found correlation between stranding positions of the animals and
areas where magnetic minima intersect the coast of Great Britain. Similar experiments have been carried out by Kirschvink and his colleagues on the east coast of
the United States. These researchers developed methods that demonstrated statistically reliable correlations of whale’s stranding sites with locations where magnetic
minima intersected the coast (Weisburd 1984 ). Result: “total intensity variations of
as little as 50 nano Tesla (nT; 0.1 % of the total fi eld) were suffi cient to infl uence
stranding location” (Walker et al. 1992 ; see also Kirschvink 1990 ; Kirschvink et al.
1985a , b , 1986 ). These results confi rm the hypothesis that mysticete species “possess
magnetic sense that they use to guide migration” (Walker et al. 1992 ).
3.5 Biomagnetite in Marine Vertebrates