People have probably always been fascinated by the behavior
of animals. Indeed an understanding of the behavior of prey
animals must have been essential to our early ancestors; their
paintings on the walls of caves suggest that they could have been
fairly familiar with behavioral concepts such as herd size and
migration. The earliest stock-farmers would have needed to
understand the behavior of the charges in their care just as their
modern counterparts do today.
Some members of society (and even some biology students)
may wrongly think of the study of animal behavior in an
academic context as being a soft science or even an easy option.
Questions for discussion
Frequently consider the connection of all things in the
universe and their relation to one another.
Marcus Aurelius AD 121–80
u The field of animal behavior is diverse and may be studied from a variety of
u It is useful to consider behaviors as adaptations.
u A single behavior will not serve, or serve the same purpose in all situations,
and behaviors are adapted to be effective in the environment of the animal
u It is wrong to think of animal behavior as a general interest or a purely academic subject. The study of animal behavior is an important science which has
a clear applied context.
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However, I hope to show you in this introduction to the subject
that it is an important and rigorous science and that it has a clear
application to some of the problems that we face in the modern
Cephalopod inking behavior
Many species of octopus and squid are known to exhibit a
particularly effective behavior that enables them to escape from
predators. In the region of their intestines the animals have a
special sac-like organ. In the wall of this sac there is a gland which
secretes a brown or black liquid rich in the pigment melanin, this
is ink. When threatened the animal has the ability to compress
the ink sac and squirt a jet of the liquid from its anus. It is thought
that the cloud of ink hanging in the water forms a dummy squid
termed a pseudomorph, which attracts and holds the attention
of the predator allowing the animal to dart away to safety. The
deception is made all the more effective because long thin species
produce long thin pseudomorphs and more round species produce rounder clouds of ink (Plate 1.1).
Squid and octopus are molluscs, taxonomic relatives of the
garden slug and snail. Can you imagine a slug squirting out ink to
leave a pseudomorph hanging in the air to decoy a bird predator
while the slug made its escape? Of course you can’t, for the simple
reason that this behavioral strategy can only work when the animal is surrounded by a medium that will support the ink cloud for
a sufficient period to allow the escape. In water this works, but in
the less dense medium of air it would not.
Plate 1.1 An animal this shape
should produce a long, thin
pseudomorph. © C. Waller.
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Essential Animal Behavior 3
Some species of octopus and squid are inhabitants of the ocean
depths. Here light penetration from the surface is minimal or zero
and the seawater is a constant inky black. Obviously the inkdummy strategy would be no more effective here than it would be
in air. The pseudomorph would hang in the water column, but it
is unlikely that an ink-black shape would be seen against the
inky-black backdrop. In this situation species such as the deepwater squid Heteroteuthis secrete a luminescent ink, creating a brief
flash of light which is thought to confuse a potential predator just
long enough for an escape to be affected.
From this example I hope that I have made a few key points
about behavior. Firstly, that behaviors are adaptations which
serve specific functions, and we will consider this point further
later in this chapter. Secondly, that a single behavior may not
serve, or serve the same function, in all situations (a point to be
borne in mind throughout this book). Finally, behaviors are
adapted to be effective in the environment of the animal performing them.
What is behavior?
Before investigating the amazing diversity of behaviors that
animals exhibit, it is necessary for us to gain some insight into
the concept of behavior itself. We need to decide what the word
behavior means to us in the current context and to examine the
various avenues open to us for the study of animal behavior.
So what is behavior? Dictionary definitions of the word typically include phrases such as “acting or functioning in a specified
or usual way.” This suggests to us that behavior is a predictable
thing. Another common phrase is “the response of an organism
to a stimulus.” This suggests that behaviors are made to happen
by something. In the case of this definition the “something” concerned is not specified, and may be internal or external to the
animal involved. Each of these ideas is in its own way an adequate
response to the question. Behaviors are in many cases predictable
given sufficient information concerning their context (although
many appear initially to be highly unpredictable). Similarly
behaviors are often linked to a stimulus in an immediate sense at
some level. The shortcoming of such definitions, however, is that
they attempt to narrowly confine behavior in an easily described
and highly specific way. Given the diversity of behavior such an
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approach may not be appropriate, because as humans we often
think of different behaviors in very different terms.
Take for example breathing, swimming, and learning. Each of
these words describes a behavior for which the definitions presented above would be sufficient. However as humans we would
probably not think of them as being equivalent conceptually.
We would consider breathing to be an involuntary process and
may not even consider it to be a behavior at all because of that.
Swimming, on the other hand, is clearly an active process, we
tend to think of it as having a motivation or goal. Learning we
think of in different terms again. We have a tendency to place it
into a higher class of processes, which require a higher level of
mental ability (though we shall see in Chapter 4 that this need
not be the case). So as a result of our own preconceptions about
the words we use to label behaviors, and their obvious diversity, it
will be much more useful for us to adopt a very broad definition
of behavior in this book.
Put more simply then behavior is a property of all living things
and whenever we observe an animal
to be engaged in any activity (voluntary or involuntary) we are witnessing behavior. Indeed it could be said
that the only animal not behaving is
a dead animal!
This is an important point to
remember. Although we may feel
that a sleeping seal or a motionless
sea-snake are doing nothing, they
are in fact behaving. The act of sleep
is a behavior in its own right, and
the snake is quite probably poised to
strike at passing prey, tensing a host
of muscles in readiness and taking in
and processing a wealth of information about its environment. There
can be no doubt that it is behaving.
Approaches to the study of animal behavior
The effective study of animal behavior requires observation and
experimentation. Before we have any chance of understanding
a behavior fully we must observe that behavior, in its natural
Focus on anthropomorphism
Anthropomorphism is the attribution of human feelings and
emotional states to animals. As humans we are aware of three
mental experiences: feelings (pain, pleasure, etc.), motivations
(the purposes of our actions), and thought. Our current
understanding of nonhuman animal species does not allow us to
say that they experience the same (of course nor does it preclude
common mental experiences). Throughout the development of
the field of animal behavior anthropomorphism and the use of