Rorquals: Fin Whale, Blue Whale,
Humpback, etc. 
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This Fin Whale was observed feeding cooperatively with
a Blue Whale of nearly the same size. It was estimated to be about 80 feet
long. Both whales were making deep dives of about eighteen minute duration
and gathering tons of Krill. In some locations the water was so thick with
Krill that it took on a red cast.
The blowhole of this Blue Whale flares as it inhales
hundreds of liters of air in a scant second.
More than six meters across, the flukes were seen
at considerable distance !
This blue whale rolled over at the surface. Look for the long parallel grooves that allow the mouth
cavity to expand.
These are the flukes of a Humpback Whale (Megaptera
novaeangliae ) that was seen about 100 miles off the coast of Santa
Barbara, California.
Frequently sea birds are seen in the vicinity of
whales. The birds flying about the flukes in this photo are called Sooty
Shearwaters (Puffinus griseus).
"Humpback
whales sometimes go up "channel ways" or fjords in Alaska. Every twenty
years or so a Humpback Whale swims up the Sacramento River in California.
Humpback
whales migrate to temperate waters to bear their young. In the Arctic the
water temperature in Winter remains near four degrees Centigrade but the
air temperature can be very low. Since the calves have much less body mass
than the adults they would probably not be able to withstand breathing
the cold air which can be as low as minus fifty degrees Centigrade."
Source:
Marine Mammals Lecture at UCSC, 1985 by Kenneth S. Norris
Humpback whales are also sometimes called Rorquals (Family Balaenopteridae)
just like the Fin Whale and the Blue Whale.
Long grooves or pleats along the ventral side allow for great
expansion of the mouth cavity. Baleen plates made of keratin protein (like
hair and fingernails) extend from the upper jaw and filter out the food
from tons of water (about 1/3 of their body mass) that they gulp into their
mouths.
Rorquals are the baleen whales that have many parallel
throat grooves. There are some other types of rorquals (balaenopterids)
that I have never seen.
A somewhat smaller rorqual that I have seen is the Minke
Whale. It is a surprisingly fast swimmer.
A new species of whale
( Balaenoptera omurai ) has been described on the basis
of DNA studies (see the BBC link below).
Selected links to other
sources of information on whales
