E B O O K F O R F A N S
KAREN CASTILLO & ANDRÉS GÓNGORA
[*Copyright © 2016 Datamatic, S.C. *]
All rights reserved. This book or any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of the publisher except for the use of brief quotations in a book review.
First Edition, 2016
Text and research: Karen Castillo
Design: Andrés Góngora.
Review: Berenice Lorenzo.
Production: Sergio Góngora.
Editorial: Datamatic, S.C.
Photos: courtesy of Pixabay and the
All images rights are property of their
authors as listed in Pixabay.
Bioexpedition and its logo are trademarks of Datamatic, S.C.
Some toothed cetaceans
Among the marine mammals, whales have a
The word “whale” is just a common name are often called whales,
leading place for features like their size.
applied to several species, but there are
like the sperm whale, the
Although they are animals adapted to aquatic toothed whales or Odontoceti; and baleen
orca, and the beluga.
life, they breathe through their lungs, give birth whales, or Mysticeti. Although rigorously only to live offspring and breastfeed like most land four species of the genera Balaena and
Eubalaena, are whales, in practice, all baleen whales, and even some toothed whales are
Whales belong to the infra-order cetaceans, a called whales.
group that includes dolphins and porpoises.
There are 15 species of baleen whales:
Pygmy right whale.
Common minke whale.
Southern minke whale.
North Atlantic right whale.
Southern right whale.
North Pacific right whale.
They all are huge animals compared to most marine creatures which have massive bodies and usually slow movements. They are essential for the ocean food chain, for being on the top of it.
DISTRIBUTION & HABITAT
Whales live in all oceans of the world, in
Whale distribution depends on many factors
The closest living relatives of
different environments and habitats. Some
related to their anatomy, their evolution, their whales are hippos as they both
spend their lives in the icy waters of the poles, diet and other requirements. Some species
descended from a semi-aquatic
while others live in warmer habitats near the have populations in all oceans around the
tropics. Similarly, some whale species reside world; these are the cosmopolitan species, like near coastal areas while some others dwell
the blue whale, which inhabits all the great mainly in open waters and rarely or never
oceans, although they do not venture into some venture close to the coast.
By contrast, only some whales live in small or very specific I
regions of the world and never leave them, like the North Atlantic right whale, which inhabits only in some areas of the Atlantic Ocean.
Several whale species tend to migrate at certain seasons, either toward the polar regions in the summer looking for food or to the tropics to give birth during the winter, but even among migratory species, there are some who prefer to stay in places close to the coasts.
If there is something particular about the anatomy of baleen
whales, it is their large size. Undeniable proof of this is the blue whale, the world’s biggest animal, with its 30 meters long.
However, there are smaller species like the pygmy right whale (Caperea marginata), which reaches at most 6.5 meters long.
All species have a fusiform body, with a thick center and thinner ends. They have two pectoral fins and tail flukes that move up and down. Some have a fin on the back. Their head is broad, and at the top, they have two spiracles, which are the openings where they breathe and get oxygen; they hermetically close them when submerged. Once the air enters the spiracles, it goes into the lungs. Two indentations in the head, almost imperceptible at plain sight, drive sounds to the ear canals.
Baleen whales have baleen instead of teeth. They are long and flexible structures composed of a protein called keratin, which filter water out and retain the food. Some have a few longitudinal folds in the lower part of their body, which expand when the whales introduce a large volume of water in their mouth.
Their skin is soft and almost smooth, but usually, display marks or scars as a result of possible fights with other whales or animals or even attached parasites. An oily substance covers the skin which reduces water friction and resistance when moving.
The body of whales has a
lighter color on the
bottom, this allows them to
blend with the water
surface if seen from
Baleen whales can consume each
Baleen whales can feed on a wide variety of
Baleens act as a filter; they filter the water out day about 4% of their body
animals, usually small fish and plankton.
and keep small organisms trapped in them, and weight.
Although toothed whales have adapted to hold then the whale swallows the trapped food. A their food, baleen whales feed on zooplankton baleen whale can filter massive amounts of food and krill, and to a lesser extent include small in this structure.
fish, copepods, and squid.
Not all species get their food the
same way. Many, swim with their
mouth open through extensive
accumulations of zooplankton, but
gray whales prefer to suck the water
and the sand of the ocean floor, to
catch small benthic creatures.
Their size could suggest that whales
eat very often, but most baleen
whales spend only 4 to 5 months a
year for feeding and survive the rest
of the year thanks to the abundant
reserves of fat and some occasions
when they capture food.
Unlike dolphins, baleen whales are less social, because
many of them spend most of their lives alone or accompanied only by their offspring. Sometimes they form temporary groups, but they are not large herds where they stay throughout their existence. Occasionally, they travel in small groups and meet in feeding areas.
Whale are intelligent creatures, gifted with the ability to communicate with each other through sounds, movements and body postures. Some whales hit the water with their tails or fins as a warning to their peers or to show excitement or aggression. Humpback whales stand out for their impressive moves and leaps out of the water, as well as their melodic
songs, frequent during the breeding season. All whales can produce sounds to communicate.
As mammals, baleen whales give birth to live young after a
long gestation period and subsequently breastfeed them.
They are polygamous, and females usually have a single calf after a gestation that lasts between 10 to 14 months, depending on the species. Youngs are unable to take care of themselves, so their mothers do it and continuously feed them for several months.
Whales cannot sleep as many
animals, but they usually rest
with half of the brain active.
Mothers and calves create a close bond that can extend after the weaning, which usually occurs around the first birthday of the calves.
They gain weight quickly, thanks to the fat-rich milk from their mother.
THE BLUE WHALE
*THE BLUE WHALE. *
Blue whales live in all oceans of the world and
Blue whales have a big appetite.
may even reach a small part of the Arctic, but An adult can consume 3,600 kilo-Balaenoptera musculus.
their largest populations dwell in particular grams of krill in a day.
This remarkable animal has the largest body of regions such as the northeast Pacific Ocean.
all living beings on Earth, and his heart is so This species has three subspecies:
colossal that exceeds the size of several large Balaenoptera musculus musculus,
animals. A blue whale can measure up to 30
Balaenoptera musculus intermedia, and
meters long and weigh up to 173 tons,
Balaenoptera musculus brevicauda, distributed exceeding the size of most known dinosaur
in particular areas each one. They usually
fossils. Females tend to be larger than males.
spend more time in the open ocean, but sometimes they get close to The blue whale is a mammal that does not generate many offspring, coastal waters.
but only one at a time. Males can compete to mate with a female, which sometimes leads to fights. After 10 to 12 months of gestation, These cetaceans differ from other baleen whales by featuring an a calf is born with about 7 meters long, and during the following elongated and relatively thin body, and a flat head on the top. Their months is breastfed and cared for with exceptional dedication by his diet is almost exclusively based on krill, although they do not mother.
discard tiny copepods and small fish. During the day, they go deep into the ocean to catch their food, and during the night they change their strategy and stay near the surface to feed.
*THE GRAY WHALE. *
This species inhabits shallow coastal waters of the North Pacific Ocean and adjacent waters and rarely reaches waters of the Arctic *Eschrichtius robustus. *
Ocean. Like other baleen whales, it feeds by filtering, but instead of The easiest way to recognize a gray whale is by the presence of a swimming with their mouth open, they usually go to the ocean floor substantial amount of parasites and other animals attached to their and sucks a lot of sediment, filter the food out with their baleen and grayish skin. The most common is a type of barnacle known as then take off the water and the sandy material. Their main foods are
“whale lice” which is embedded mostly in the head and makes their benthic crustaceans.
skin look with whitish and orange spots.
Gray whales are curious animals, and it is common to see them taking their head out of the water to watch the boats.
Sometimes they breach or jump out of the water, possibly as a form of communication or to remove the parasites from their skin. They are seen often traveling alone or in small groups; higher concentrations are only for feeding or reproduction. It is a migratory species and is probably the mammal with the longest migration.
Currently, the gray whale is not endangered, but for a long time has been affected by commercial whaling, which ended its Atlantic Ocean populations several centuries ago.
Gray whales were called
“devil fish” once because of
their violent reactions to
defend their young and
themselves from attacks either
from humans or other
*THE HUMPBACK WHALE. *
*Megaptera novaeangliae. *
The humpback whale has a robust body and a head with lumps or bumps and large pectoral fins that reach up to one-third of their body length. Adults are 12 to 16 meters long and weigh between 25 and 30 metric tons. It is common that they have attached parasites in their head.
This species is found in all oceans and during summer their number increases in the Antarctic region. They prefer shallow habitats. When dwelling Antarctic waters they feed on krill, but their diet also includes small fish such as Atlantic salmon, capelin, herring, mackerel, and haddock. One of their most popular hunting methods includes blowing to form bubble columns that enclose their prey.
During summer, humpback whales travel to feeding areas located at high latitudes, and during winter they migrate to breeding areas in tropical or subtropical waters. However, the population of the Arabian Sea stays in the region throughout the year. During the breeding and gestation period, they survive on their fat reserves, as they only feed during the summer.
Like most baleen whales, they only have one offspring per litter, born after a gestation period of 11-11.5 months. The mother feeds her calf with breast milk for several months, and when summer arrives, they travel together to the feeding areas.
The humpback whales are not endangered now, but they are continuously threatened by commercial fishing and bycatch.
Only humpback whale
males produce songs. The
general belief is that they
do it to attract females
during the breeding
Whales have no natural predators, but
young or weak individuals can fal prey
to large carnivores, especial y sharks.
centuries was part of an ordinary
economic activity, since fat, meat,
For a long time, whales have been
beards and other body parts were
threatened by fishing and other human
traded. But over the years their
activities. Many die after colliding with
population began to decline, raising
large ships and because of the pollution
concerns among people that started to
of their habitat, while excessive noise
protect them. In 1982 the International
and the effects of climate change on
Whaling Commission imposed a
oceans affect the availability of their food moratorium to end commercial whaling,
and can alter their migration routes. At
which came into effect in 1985-1986.
present, the blue whale (Balaenoptera
musculus), the fin whale (Balaenoptera
Not all countries agreed to end
physalus), the North Atlantic right whale
commercial whaling, despite the risks
(Eubalaena glacialis), the northern
that this entails. However, many
Pacific right whale (japonica Eubalaena)
organizations are struggling to prevent
and the sei whale (Balaenoptera
massive deaths of these magnificent
borealis) are in danger of extinction.
Hunting of whales and other cetaceans
during the XVII, XVIII, XIX and XX
Whale are marine mammals which have massive bodies and usually slow movements. Whales belong to the infra-order cetaceans, a group that includes dolphins and porpoises. Although rigorously only four species of the genera Balaena and Eubalaena, are whales, in practice, all baleen whales, and even some toothed cetaceans are called whales.