HOW A HUMPBACK DIVES AND SPOUTS
Although it had been possible to secure but few good pictures during my
first trip at sea on the _Orion_, nevertheless I had learned much about
the ways of humpbacks. One impression, which I subsequently found to be
correct, was that this would prove to be the most interesting of all
large whales to study—at least from the standpoint of its habits.
There are no dull moments when one is hunting a humpback, for it is
never possible to foretell what the animal’s next move will be. He may
dash along the surface with his enormous mouth wide open, stand upon his
head and “lobtail,” throwing up clouds of spray with smashing blows of
his flukes, or launch his forty-ton body into the air as though shot
from a submarine catapult.
He may do dozens of other highly original things, all of which show his
playful, good-natured disposition and, if he is allowed to continue his
elephantine gambols unmolested, he is as harmless as a puppy. But once
imbed an iron in his sensitive flesh and it is wise to keep well beyond
the range of his long flippers and powerful flukes which strike the
water in every direction with deadly, crushing blows.
The humpback is the whale which is most usually seen from the Atlantic
passenger vessels, and may easily be recognized because when “sounding,”
or going under for a deep dive, the flukes are almost invariably drawn
out of the water; the finback and blue whales, the two other common
species, seldom show the flukes.
[Illustration:
A humpback whale “sounding.” “The humpback comes up obliquely, and, as
soon as the spout has been delivered, arches the back and begins to
revolve.”
]
When a humpback dives the easy grace with which the animal manipulates
its huge, ungainly body and great propeller-like tail, drawing it out of
the water smoothly but with irresistible force, always gives me a thrill
of admiration. I remember one day, while crossing the Atlantic on the
_Kronprinz Wilhelm_, a humpback came up not far from the ship and swam
parallel with her for several minutes. Each time the big fellow drew
himself up, slowly rolled over, and brought his flukes out, an
involuntary cheer went up from the passengers. But it is only when
sounding that the tail is shown and never when the whale is feeding or
swimming near the surface.
[Illustration:
A humpback whale with a very white breast. The side fins, or flippers,
are almost one-quarter the entire length of the animal, and to them
barnacles attach themselves as well as to the folds of the throat
and breast.
]
The humpback comes up obliquely and, as soon as the spout has been
delivered, arches the back and begins to revolve, finally drawing out
the flukes and going down vertically. When hunting, the proper time to
shoot is when the dorsal fin begins to show above the water—depending,
of course, upon the distance. The iron then has a fair chance to reach
the lungs or heart and a larger target is presented.
How far a whale can descend is a matter of conjecture and more or less
dispute among naturalists. One writer argues that whales cannot go
deeper than three hundred feet because of the tremendous water pressure.
But all cetaceans have certain specializations in body structure which
undoubtedly enable them to withstand high pressure.
I have, as personal evidence upon this subject, the fact that a blue
whale, harpooned between the shoulders and but slightly injured, dove
straight downward and took out over a quarter of a mile of rope. We
were, at the time, almost a hundred miles at sea and so far as could be
determined the animal had gone down to the full limit of the line which
hung from the bows as rigid as a bar of steel. The whale remained below
for thirty-two minutes and reappeared not more than a hundred yards away
and directly in front of the ship.
It is the opinion of every whaler with whom I have talked that all the
large cetaceans can descend to a considerable depth, and each man will
give numerous instances, similar to the one I have cited in the case of
the blue whale, to prove his point. Until further information is
available this subject must be an open one. A smooth, circular patch of
water is always left at the spot where a large whale dives. This is
undoubtedly produced by suction and interrupted wave action but has
given rise to many ingenious and absurd theories in explanation.
When studying whales the most important fact to remember is that _they
are one-time land mammals which have taken up a life in the water_ and
that their bodily activities, although somewhat modified, are
nevertheless essentially the same as those of a horse, cow, or any other
land mammal.
Since a whale breathes air, when it is below the surface the breath must
be held, for if water should be taken into the lungs the animal would
drown. Thus, as soon as a cetacean comes to the surface its breath is
expelled and a fresh supply inhaled before it again goes down, just as
in the case of a man when diving. However a whale is able to hold its
breath for a much longer time than can an ordinary land mammal—even as
much as forty-five minutes or an hour.
When the animal comes to the surface the breath which has been contained
in the lungs under pressure is highly heated, and as it is forcibly
expelled into the colder outer air it condenses, forming a column of
steam or vapor. A similar effect may be produced by any person if, on a
frosty morning, the breath is suddenly blown out of the mouth. I have
often seen a whale blow when its head was still a short distance under
the surface and at such times a little water will be thrown upward with
the spout.
[Illustration:
The tail of the humpback as the animal “sounds” looks like a great
butterfly which has alighted upon the water.
]
That whales spout out of the blowholes water which has been taken in
through the mouth is probably more widely believed than any other
popular misconception. As a matter of fact such a performance would be
impossible because a whale’s nostrils do not open into the back of the
mouth as do those of a man, and the animal is not able to breathe
through its mouth as do ordinary land mammals.
Instead, an elongation of the arytenoid cartilages and the epiglottis
fits into the soft palate, thereby forming a continuous passage between
the nostrils and the trachea, or windpipe, and entirely shutting off the
nasal passages from the mouth. In this way a whale can swim with its
mouth open, when feeding, without danger of being strangled by getting
water into the breathing organs.
The blowholes, or nostrils, have been pushed backward and upward to open
on the top of the head instead of at the end of the snout. This is an
adaptation to aquatic life, which is also seen in other water mammals,
for in this way the nostrils are almost the first part of the body to
appear at the surface and the whale can begin to breathe immediately
upon rising.
Although all the fin whales have two nostrils, the spout ascends in a
single column, which, in the humpback, is from twelve to fifteen feet
high. The cloud of vapor is narrow at the base but spreads out at once,
forming a low bushy column which rapidly drifts away.
The height and density of the spout in all whales depends upon the
animal’s size and the length of time it has been below. If the whale has
been submerged but a brief period, as during surface dives, a
comparatively small quantity of air is expelled and the breath has not
had time to become highly heated; consequently the column will be low
and thin.
The first spout after sounding is usually the highest and fullest. I
have seen humpbacks, which had been badly wounded, lying at the surface
close to the ship, blowing every few seconds, and the spout could hardly
be seen although the opening and closing of the blowholes and the
metallic whistling of the escaping breath were plainly distinguishable.
Immediately after the delivery of the spout the lungs are refilled, the
blowholes being opened widely and protruded upward, and the breath
rapidly drawn in. The elevation of the blowholes is probably to prevent
a wave from slopping over and filling the nasal passages, but when a
whale lies dead upon the slip there is no indication that the nostrils
can be protruded. This was first learned through a photograph of a
spouting blue whale, taken by Dr. Glover M. Allen in Newfoundland
waters, and since then I have secured two others which show it
admirably. At the time my first picture was taken we had an interesting
experience which I shall never forget.