Title: DID YOU KNOW...
1DID YOU KNOW...
2FEBRUARY IS...
3HUMPBACK WHALE AWARENESS MONTH?
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5Please INCLUDE these majestic creatures in your
thoughts this month.
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8Taxonomy and Evolution
The Humpback is the sole member of the genus
Megaptera, and is usually classified in its own
subfamily Megapterinae within the family
Balaenoptiidae, which contains eight other
baleens whales. The literal translation of the
binomial name is the New England big-wing,
which reflects the large flippers and the
location of the first described specimen. More
recent genetic studies indicate that the first
filter-feeding whales, of which the Humpbacks are
a descendant, arose in the late Eocene period
35-36 million years ago, and that species
evolution then slowed for a long time before
radiating again in the middle of the Miocene
period, 12-15 million years ago. It is not known
whether the Humpback species itself arose at this
time. However, the evidence does indicate that
the fin and blue whales lineages separated more
than 5 million years ago, and that these species
split after the Humpback did. The Humpback Whale
species is therefore between 5 and 12 million
years old. Like other cetacean species, though,
the Humpback fossil record becomes very patchy at
times greater than 2.5 million years ago, and it
is not currently possibly to narrow this age
range further.
9Humphrey
Probably the most famous humpback whale is
Humphrey, who was rescued twice by The Marine
Mammal Center and other concerned groups. The
first rescue was in 1985, when he swam into San
Francisco Bay and then up the San Joaquin River.
Five years later, Humphrey returned and became
stuck on a mudflat in San Francisco Bay near 3
COM Park. He was pulled off the mudflat with a
large cargo net and the help of a Coast Guard
boat. Both times he was successfully guided back
to the Pacific Ocean using a sound net in which
people in a flotilla of boats made unpleasant
noises behind the whale by banging on steal
pipes, a Japanese fishing technique known as
oikami. At the same time, the attractive sounds
of humpback whales preparing to feed were
broadcast from a boat headed towards the open
ocean. Since leaving the San Francisco Bay in
1990, Humphrey has been seen only once, at the
Farallone Islands in 1991.
10Population and Distribution
The Humpback Whale is found in all the major
oceans, in a wide band running from about 60 S
to 65 N latitude. It is a migratory species,
spending its summers in cooler, high-latitude
waters, but mating and calving in tropical and
sub-tropical waters. Annual migrations of up to
25,000 km (16,000 miles) are typical, making it
one of the best-traveled of any mammalian
species. An exception to this rule is a
population in the Arabian Sea, which remains in
these tropical waters year-round. The species is
not found in the eastern Mediterranean, the
Baltic Sea or the Artic Ocean. The Humpback
Whale appears to be recovering much more strongly
from the effects of whaling than the other large
whales. The population has grown from a low point
of 20,000 at the 1966 moratorium to about 35,000
today. By contrast, the blue whale population has
remained static at 3,000 over the same period.
There are estimated to be 11,600 Humpbacks in the
North Atlantic, 7,000 in the North Pacific and at
least 17,000 in the Southern Hemisphere.
11Physical Description
Humpback Whales can easily be identified by their
stocky bodies with obvious humps and black upper
parts. The head and lower jaw are covered with
knobs called tubercles, which are actually hair
follicles and are characteristic of the species.
The tail flukes, which are lifted high in the
dive sequence, have wavy rear edges. The long
black and white tail fin, which can be up to a
third of body length, and pectoral fins have
unique patterns, which enable individual whales
to be recognized, in a similar way to the bill
markings on Bewicks Swans. Humbacks have 270 to
400 darkly colored baleen plates on each side of
the mouth. Ventral grooves run from the lower jaw
to the umbilicus about halfway along the bottom
of the whale. These grooves are less numerous
(usually 16-20) and consequently more prominent
than in other rorquals. The stubby dorsal fin is
visible soon after the blow when the whale
surfaces, but has disappeared by the time the
flukes emerge. It has a distinctive 3 m (10 ft)
busy blow. The calf is about 4-4.5 m (13-15 ft)
long when born and weighs approximately 700 kg
(1500 lbs). Calves are nursed by their mothers
for their first six months, then are sustained
through a mixture of nursing and independent
feeding for a further six months. Calves leave
their mothers at the start of their second year,
when they are typically 9 m (30 ft) long. Both
sexes reach sexual maturity at the age of five.
Full adult size is achieved a littler later.
Grown size is commonly 15-16 m (49-52 ft) in
males, 16-17 m (52-56 ft) in females, and a
weight of 40,000 kg (or 44 tons) the largest
ever recorded specimen was 19 m (62 ft) long and
had pectoral fins measuring 6 m (20 ft) each.
Humpback Whales can live for 40-50 years.