Pilot whales are one of the most common inshore species in Newfoundland,
especially when squid, their primary food, are plentiful. They can be seen as
early
as May, and stay inshore as late as October. In winter, these whales
are thought
to range from the Grand Banks as far south as North Carolina.
Group of pilot whales
appearing on the sea surface.
There may have once been as many as 50,000 pilot whales in Newfoundland
waters. Whaling for this species in Newfoundland was done by driving groups
of animals ashore, and one year in the mid-1950s about 10,000 were killed.
Whaling was discontinued in 1972 because of decimated local stocks and poor
markets for the meat, which was typically sold to fur farms.
Female pilot whales mature at 6 years of age and a length of about 3.5 m.
Males
mature much later when 12 years old and 5 m in length. Mature adult
males,
which are generally larger than females, can weigh as much as 3
tons. At birth,
calves weigh slightly over 200 lbs. The are born after a
pregnancy of 16 months,
and are weaned at around 20 months of age.
Pilot whales have strong social cohesiveness; it is rare to see a single
individual.
Even when being driven ashore by whalers, they would stay
together as a group.
Groups typically contain animals of both sexes and
many different ages. The
males may compete for breeding privileges,
forming a hierarchy that excludes
smaller males. Large assemblages may
also be composed of smaller, close-knit
groups which are stable over time.
Pilot whales are some of the noisiest whales in Newfbundland waters. Their
group structure requires social communication, and they orient to prey objects
by echolocation. Vocalizations include a wide variety of whistles and clicks.
Occasionally, groups of pilot whales slowly swim ashore and beach them-
selves. Such mass standings are a natural phenomenon and have been observed
throughout history. The reasons for mass strandings are not understood. One
possibility is that some or all of the animals in the group are sick, or have
parasites
that affect their navigational system. In many cases, strandings
occur at gently
sloping, sandy beaches, which may distort the whale's
sonar, making it difficult
for the animal to determine direction or depth.
Some scientists have suggested
that mass strandings occur at sites where
there are unusual magnetic fields. The
presence of bait very close to
shore may also be a factor. It is probably best to think
of mass
strandings like any accident where, rather than a single cause, a number
of
factors probably contribute.
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