The
humpback
whale
is
one
of
the
rorquals,
a
family
that
includes
the
blue
whale,
fin
whale,
Bryde's
whale,
sei
whale,
and
minke
whale.
Rorquals
have
two
characteristics
in
common:
dorsal
fins
on
their
backs,
and
ventral
pleats
running
from
the
tip
of
the
lower
jaw
back
to
the
belly
area.
The
shape
and
color
pattern
on
the
humpback
whale's
dorsal
fin
and
fluke
(tail)
are
as
individual
in
each
animal
as
are
fingerprints
in
humans.
The
discovery
of
this
interesting
fact
changed
the
course
of
cetacean
research
forever,
and
the
new
form
of
research
known
as
"photo-identification,"
in
which
individuals
are
identified,
catalogued,
and
monitored,
has
led
to
valuable
information
about
such
things
as
humpback
whale
population
sizes,
migration,
sexual
maturity,
and
behavior
patterns.
PHYSICAL
DESCRIPTION
The
head of a
humpback
whale is
broad and
rounded when
viewed from
above, but
slim in profile.
The body
is not as
streamlined
as other
rorquals,
but is quite
round, narrowing
to a slender
peduncle
(tail stock).
The top of
the head
and lower
jaw have
rounded,
bump-like
knobs, each
containing
at least
one stiff
hair. The
purpose of
these hairs
is not known,
though they
may provide
the whale
with a sense
of "touch."
There are
between 20-35
ventral grooves
which extend
slightly
beyond the
navel.
COLOR
The body
is black
on the dorsal
(upper) side,
and mottled
black and
white on
the ventral
(under) side.
This color
pattern extends
to the fluke.
When the
humpback
whale "sounds"
(goes into
a long or
deep dive)
it usually
throws its
fluke upward,
exposing
the black
and white
patterned
underside.
This pattern
is distinctive
to each whale.
The flippers
range from
all white
to all black.
FINS
AND FLUKE
About 2/3
back on the
body is an
irregularly
shaped dorsal
(top) fin.
Its flippers
are very
long, between
1/4 and 1/3
the length
of its body,
and have
large knobs
on the leading
edge. The
fluke (tail),
which can
be 18 feet
(5.5 m) wide,
is serrated
and pointed
at the tips.
LENGTH
AND WEIGHT
Adult males
measure 40-48
feet (12.2-14.6
m), adult
females measure
45-50 feet
(13.7-15.2
m). They
weigh 25
to 40 tons
(22,680-36,287
kg).
FEEDING
Humpback
whales feed
on krill,
small shrimp-like
crustaceans,
and various
kinds of
small fish.
Each whale
eats up to
1 and 1/2
tons (1,361
kg) of food
a day. As
a baleen
whale, it
has a series
of 270-400
fringed overlapping
plates hanging
from each
side of the
upper jaw,
where teeth
might otherwise
be located.
These plates
consist of
a fingernail-like
material
called keratin
that frays
out into
fine hairs
on the ends
inside the
mouth near
the tongue.
The plates
are black
and measure
about 30
inches (76
cm) in length.
During feeding,
large volumes
of water
and food
can be taken
into the
mouth because
the pleated
grooves in
the throat
expand. As
the mouth
closes water
is expelled
through the
baleen plates,
which trap
the food
on the inside
near the
tongue to
be swallowed.
MATING
AND BREEDING
Humpback
whales reach
sexual maturity
at 6-8 years
of age or
when males
reach the
length of
36 feet (11.6
m) and females
are 40 feet
(12 m). Each
female typically
bears a calf
every 2-3
years and
the gestation
period is
12 months.
A humpback
whale
calf is between
10-15 feet
(3-4.5 m)
long at birth,
and weighs
up to 1 ton
(907 kg).
It nurses
frequently
on the mother's
rich milk,
which has
a 45% to
60% fat content.
The calf
is weaned
to solid
food when
it is about
a year old.
DISTRIBUTION
AND MIGRATION
Found in
all the world's
oceans, most
populations
of humpback
whales follow
a regular
migration
route, summering
in temperate
and polar
waters for
feeding,
and wintering
in tropical
waters for
mating and
calving.
NATURAL
HISTORY
At least
3 different
species of
barnacles
are commonly
found on
both the
flippers
and the body
of the humpback
whale. It
is also home
for a species
of whale
lice, Cyamus
boopis.
Humpback
whales are
active, acrobatic
whales. They
can throw
themselves
completely
out of the
water (breaching),
and swim
on their
backs with
both flippers
in the air.
They also
engage in
"tail lobbing"
(raising
their huge
fluke out
of the water
and then
slapping
it on the
surface)
and "flipper
slapping"
(using their
flippers
to slap the
water). It
is possible
that these
behaviors
are important
in communication
between humpbacks.
Perhaps
the most
interesting
behavior
of humpback
whales is
their "singing."
Scientists
have discovered
that humpback
whales sing
long, complex
"songs."
Whales in
the North
American
Atlantic
population
sing the
same song,
and all the
whales in
the North
American
Pacific population
sing the
same song
but the songs
of each of
these populations
and of those
in other
areas of
the world
are uniquely
different.
A typical
song lasts
from 10-20
minutes,
is repeated
continuously
for hours
at a time,
and changes
gradually
from year
to year.
It appears
that all
the singing
whales are
males and
that the
songs may
be a part
of mating
behavior.
STATUS
Because their
feeding,
mating, and
calving grounds
are close
to shore
and because
they are
slow swimmers,
the humpback
whales were
an easy target
for early
whalers.
Between 1905
and 1965,
28,000 humpback
whales were
killed. The
International
Whaling Commission
(IWC) gave
them worldwide
protection
status in
1966. It
is believed
they number
about 15,000-20,000
at present,
or about
15-20% of
the original
population.
Humpback
Whale
Distribution
Map
Blow,
Dorsal
Fin
and
Fluke
Diagram
Byron
Bay Online
Guide.
Whale Watching
and Information,
Humpback
Whale Fact
Sheet.
