A “strand” is a beach or land bordering a body of water, and stranding is defined
as running aground.
The term stranded also refers to any creature left in a helpless
position, such as a marine mammal that comes ashore ill, weak, or simply lost (Geraci
and Lounsbury 2005).
This paper will discuss mass strandings in marine mammals, the
general biology of the marine mammals that mass strand, and the theories as to why they
Single strandings are more common than mass strandings, with the cause of them
typically being poor health, parasites, wounded or orphaned (Prescott
cause of mass strandings, however, is much harder to determine and is still puzzled over
A mass stranding is defined as an event in which two or more individuals of the
same species, not including a single cow-calf pair, beach within a close distance to one
another (Dierauf and Gulland 2001).
It is mainly the odontocetes that are involved in
mass strandings, and among them a few species predominate; these include: long and
short finned pilot whales
false killer whales
Atlantic white sided-dolphin
species that has shown up more recently in mass strandings is the Cuvier’s beaked whales
Some of the theories as to why marine mammals mass strand
include: social structure, complex topography, geomagnetic anomalies, disease or injury,
or acoustic disturbances.
The biology of the animals that strand can provide clues as to why these marine
mammals are typically involved in mass strandings.
The long and short-finned pilot
get their name from a
belief that a single member of a pod pilots, or leads the group, and that the others