Pygmy Sperm Whale

The Pygmy Sperm Whale – kogia breviceps The Firecracker Whale by Max Newman April 1996. A then-current study of available information on this remarkable whale


The Firecracker Whale
A Compilation of Available Information on Kogia breviceps
The Pygmy
Sperm Whale

by M. Maxwell A. Newman
Fairbanks, Alaska – April 15, 1996



Abstract


This paper examines the body of available information on kogia breviceps,
commonly known as the pygmy sperm whale. Research from strandings of pygmy sperm
whales comprise the basic knowledge of this intriguing creature. They are thought
to range throughout tropical and temperate waters, but are considered rare. Much
smaller than the 15 meter sperm whale and slightly larger than the 3 meter dwarf
sperm whale, these three are the only known members of the suborder odonteceti or
toothed whales. First identified in 1838 by the Compte de Blainville, it has been confused with
porpoises and sharks. The pygmy sperm whale also exhibits certain behavior unknown
in other whales for which it had been given the nickname the "firecracker"
whale.


Strandings and sightings are being reported more frequently, but perhaps only due
to an increased awareness of cetaceans in general and improved abilities to identify
them in their natural habitat. There is also evidence of environmental debris that
is causing more pygmy sperm whales and other marine species damage.


Despite efforts to help sick or injured pygmy sperm whales back to health, nearly
all have not survived in captivity. The 1981 record remained at 25 days until 1994
when, after six months, a healthy juvenile pygmy sperm whales was released off the
coast of Florida. There has been no effort to keep pygmy sperm whales in captivity
– the goal has always been to release the animal once it was healthy enough to cope
in its natural environment.



Table of Contents

  1. Introduction
  2. Physical Characteristics
  3. Location and Migration
  4. Diet
  5. Behavior
  6. Mating and Reproduction
  7. Summary
  8. Bibliography
  9. Miscellaneous Achived Articles



1.Introduction

Kogia breviceps (or pygmy sperm whale) is one of the three known odontocete
whales or toothed whales. The other two odontocete whales are the larger sperm whales
and the slightly smaller dwarf sperm whales. See table 1 and figure 1. It has been
confused with being a porpoise, much like the dwarf sperm whale, which is called
a rat porpoise in the Lesser Antilles in the Caribbean Ocean. It has markings of
a pseudo-gill that has also led to its being thought of as a shark.


First discovered and identified as a separate species by the Compte de Blainville off the Cape of Good Hope (Australia) in 1838, there remained some controversy for some time over
the classification of the pygmy sperm whale. The American Naturalist of 1871 had an article describing the current state of classification of kogia breviceps, including the controversy over the name ‘kogia’ not being suitable for the classical Latin naming system developed by Linnaeus. It was called ‘barbarous and undefined’ and others favored the more Latin sounding name ‘euphysetes’ (meaning good or easy blower), yet the name ‘kogia’ has remained. It was humorously suggested in this article that the name euphysetes may be applied to those so concerned about the name.



2. Physical Characteristics

Adult pygmy sperm whales range from 2.7 – 3.4 meters in length. They have three stomachs
and can weigh 318-408 kilograms. They have spherical type heads with an underslung
lower jaw containing 10-16 pairs of long, curved, sharp teeth in each. The upper
jaw has no teeth. They have a stocky body and a blowhole that is asymmetrical and
leans to the left. The dorsal (or top) side of these whales is a dark brown-black
which shades gradually to a grayish-white on the belly’s ventral flanks. Behind each
eye is a dark patch resembling a fish gill the height of the head region. The tiny
falcate dorsal fin is located to the rear of the midback. Unlike the giant sperm
whale (physeter catadon or physeter macrocephalus), the pygmy sperm
whale dorsal fin is well-defined.


While having two nostrils, the left is substantially larger than the right. This
led M. Carvin to conclude that the left nostril is primarily associated with breathing
functions and the right, along with surrounding soft tissues, was intended for sound
production of clicking. He speculated that kogia has become so anatomically specialized
in efficient click production that the whale has lost the ability to produce whistles.


The pygmy sperm whale, like the other sperm whales, have a melon shaped area above
the skull that acts to produce the sounds for echolocation. Although the pygmy sperm
whale has ears, the earholes are plugged with wax. This whale actually "hears"
by detecting vibrations on a very thin section of bone on the lower jaw, which is
then transmitted to the earbone. The melon acts to focus and transmit sounds the
whale creates for its various purposes.



3. Location and Migration

The kogia species can be found in all temperate and tropical waters throughout the
world. Observations and strandings are noted on the Atlantic, Gulf and Pacific Coasts
of the United States, Australia, eastern and southern Africa, the Philippines, Japan,
India, Europe, South America. It is not known how far it may or may not migrate.
It is considered as a deep water whale.


4. Diet

The pygmy sperm whale is known to eat mostly octopus and squid, but will also eat
crabs, small fish, and other invertebrates such as jellyfish. The National Aquarium
in Baltimore reported adult pygmy sperm whales can eat 25-30 lb. daily. Their relatives,
the dwarf sperm whale, have been shown to descend to depths of 300 meters to obtain
fish. The pygmy sperm whales method of hunting is unknown in the wild, but recent
experiences with Inky (see below) may offer some clues. In addition, K. Beckman stated
that kogia uses its sonar abilities to stun or debilitate it’s favorite food
– squid.


5. Behavior

Our knowledge of pygmy sperm whales behavior in the wild is limited due to the fact
that it is not a coastal animal and prefers to inhabit the deeper sections of the
oceans. They are known to travel individually or in groups of 2-3.


There are similarities to other cetacea, such as using echolocation as documented
by Michael John Carvan III, but there seem to be more differences. When diving, they
do not roll forward at the surface as do most other whales. Rising slowly to the
surface to breath, they breach and blow inconspicuously. They have been observed
with their tail hanging low in the water beneath them. Recent experience with ‘Inky’
(see below) has added a new dimension of understanding this amazing creature.


The most unique behavior of the pygmy sperm whales is they use a system of ejecting
a red-ish brown fluid from their colon, called ‘inking’. They do this when excited,
scared, or foraging. Porpoising, breaching, and speed swimming and other high energy
behaviors related to inking, have been described by those who have maintained pygmy
sperm whales in a rehabilitation setting. The Japanese fisherman have called the
pygmy sperm whale ‘tsunabi’, the rocketing firework. A more passive precursor to
inking has also been noticed as the whale rests motionless on the surface of the
water, a behavior the Japanese name Uik-Kujira or floating whale. The whale would
then nearly somersault underwater while inking. Observed by the National Aquarium,
the pygmy sperm whales named Inky was found to use inking to camouflage and confuse
squid, then located the squid by sonar through the ink and ate them.


The second unknown behavior of the pygmy sperm whales was a process of regurgitation.
One of the primary sources of food for the pygmy sperm whales is squid, which have
an inedible beak and pens. Recent observation has offered the opinion that they regurgitate
from the first or second stomach to void these and other inedible objects.


Unfortunately, pygmy sperm whales don’t seem to be able to distinguish between plastic
bags, mylar balloons and another of their favorite foods – jellyfish. This was the
cause of the New Jersey stranding of a juvenile female pygmy sperm whale on Thanksgiving
Day 1993. She was evacuated to the National Aquarium in Baltimore. After two months
of poor eating and constant regurgitation, an endoscopy was performed which discovered
numerous plastic items in the stomachs, along with a high concentration of compacted
quid pens and peaks. Once cleared of this debris, the animal began gaining weight.
From necropsies of pygmy sperm whales performed, it was estimated that the females
would regurgitate every 2.1-2.5 days, but male a more frequent 1.2-1.6 days.


The pygmy sperm whale and its relative dwarf sperm whale are the second most commonly
stranded cetacean in the south eastern U.S., next to the bottlenosed dolphin. The
thesis of Victoria Credle explored the influence of environmental magnetic phenomenon
may have on the magneto-receptive abilities of kogia based upon 384 stranding from
N. Carolina to Texas. She found a correlation with areas that normally had high coastal
magnetic fields and experienced sharp changes in magnetic field as well as during
periods of low magnetic activities.



6. Reproduction and Mating

Not much is known about pygmy sperm whales reproduction and mating. It is known that
mothers have one calf with a gestation of 11 months. One source suggests that calves
are typically born in the late spring. Young are about 47 inches at birth. Males
are sexually mature at 2.7 to 3 meters, females at 2.6-2.7 meters. A more detailed
study that details the normal female reproductive anatomy by Kimberlee Beckman in
her masters thesis has helped to further that cause, but still much remains to be
learned.


7. Summary

In conclusion, the information that I found was extremely unexpected, as there was
much more available than I had thought possible. However, there is obviously still
a great amount to learn. It is ironic that our body of knowledge is lacking because
we haven’t had the exposure to this species as we have other whales that have been
hunted commercially.


The high number of pygmy sperm whale strandings continues to be of concern and further
study is warranted. This shy whale is not currently endangered, but is certainly
being harmed from environmental solid waste. It exhibits very special and interesting
characteristics. I hope this information is as interesting for you to read about
as it was for me to find it.



8. Bibliography


  • Beckmen, Kimberlee B., Gross and Microscopic Anatomy of the Female Reproductive Tracts of the Dwarf and Pygmy Sperm Whales, Master’s Thesis, University of Miami, May 1986.
  • ibid, personal conversations, March 1996.
  • Carvan III, Michael John, The Descriptive Anatomy of Sound Production and Propagation Tissues in Kogia spp. Using Magnetic Resonance and Computer Tomography Imaging, Masters Thesis, University of Miami, August 1988.
  • Credle, Victoria R., Magnetite and Magnetoreception in Stranded Dwarf and Pygmy Sperm Whales, Master’s Thesis, University of Miami, August 1988.
  • Elsberry, Wesley R. Protected Marine Species Resources: Listing by Species, Internet source, March 1996.
  • Ettlin, David Michael, "Whale’s Stomach Tells Tale of Pollution", The Sun
    (newspaper), Baltimore, January 7, 1994.
  • ibid., "Rescued pygmy sperm whale ‘Inky’ is well again and soon will swim free",
    The Sun (newspaper), Baltimore, May 1994.
  • ibid., "A leap and a dive – and Inky’s on her own", The Sun (newspaper),
    Baltimore, June 8, 1994.
  • Gill, Theodore, American Naturalist, "The Sperm Whales, Giant and Pygmy, April 1871.
  • Gunter, Gordon, Hubbs, Carl L., Beal, M. Allan, Records Of kogia breviceps
    From Texas Remarks On Movements And Distribution
    , Journal of Mammology, May 1955.
  • Kummerer, Robert, letter to newsgroup, Internet source, Jan 26, 1996.
  • Kummerer, Robert, personal Email communications, March 1996.
  • McGowan, Tom, Album of Whales, Rand McNally & Co., 1980.
  • Missehara, Lou, "A whale of a happy ending", article in Florida Today (periodical), June 1994.
  • National Aquarium in Baltimore, Pygmy Sperm Whale Fact Sheet, National Aquarium, 1995.
  • Palm Beach Post Wire Services, "Inky the whale disappears off Georgia"
    (newspaper), June 1994.
  • Pitt, Valerie, Hoke, Helen, Whales, Franklin Watts, 1973.
  • Roest, Aryan I, Thurmond, William, Montgomery, David H., Pygmy Sperm Whales in Georgia, Journal of Mammology, May 1955.
  • Schofield,T. David, Observations on Inking and Regurgitation in a Juvenile Female
    Pygmy Sperm Whale, Kogia breviceps
    , National Aquarium in Baltimore, draft
    paper March 1996.
  • Sylvestre, J.P., Review of Kogia Specimens Kept Alive in Captivity, unknown
    publication, est. 1981.
  • author unidentified, Dwarf Sperm Whales, from the Lesser Antillean Island of St.
    Vincent
    , Journal of Mammology, May 1973.
  • source unidentified, Pygmy Sperm Whale, page 88, provided by Karin Cooper, Fairbanks, Alaska, 1996.



9. Miscellaneous Archived Articles and Links

For further information, email Max Newman at max(at)chena.org

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