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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 about







Animal welfare



Questions for discussion

Essential Animal


An Introduction

Frequently consider the connection of all things in the

universe and their relation to one another.

Marcus Aurelius AD 121–80

Key points

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

performing them.

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

anthropomorphic language has