Chapter 35: Animal Behavior

Section 1: Elements of Behavior

Behavior and Survival

• The behavior of an animal is just as important to its survival and reproduction as any of its physical characteristics

• For that reason, animal behaviors have evolved in many different ways, just as animal physical characteristics have

• Behavior is in an organism’s genetic makeup• Behaviors can enhance an animal’s ability to

survive

Behavior and Survival

• There are some behaviors that animals must perform automatically in order to survive

– “Know” how to hunt soon after they are born

– Dolphins must know in advance that they have to hold their breath under water

• Other behaviors must be more flexible and capable of being changed by experience

– Hummingbirds must learn to find food in different kinds of flowers at different times of the year

Behavior and Survival

• A variety of automatic and flexible behaviors exist in the animal kingdom

– Instinct

– Learning

Instincts

• Instincts are behaviors that can be called inborn

• Instincts are built into an animal’s nervous system and cannot be changed during the animal’s lifetime, even by learned experiences

• Instinctive behaviors are genetically controlled• Many instinctive behaviors consist of actions

that always continue in a certain order once they have begun

Instincts

• Although some instinctive behaviors are relatively simple, others can be very complex

– Web-building behavior in spiders

– Courtship behaviors in insects, fish, birds, and mammals

Learning

• Learned behaviors are shaped by experience

• Learning is the way animals change their behavior as a result of experience

• Learning is valuable to an animal because it may enhance the animal’s chances of survival and its chances of reproduction and passing on its genes to another generation

Learning

• There are several different ways in which animals learn

– Habituation

– Classical conditioning

– Operant conditioning

– Insight learning

Learning

• Habituation is a decrease in response to a stimulus that neither rewards nor harms an animal

– One of the simplest ways in which animals learn

– EXAMPLE

• Very young ducks and geese are frightened of any shadow that moves overhead

• Within a few days of hatching, however, the young birds find that some shadows moving overhead – the shadows of adult geese and ducks – mean nothing

• They soon habituate to these shadows and no longer try to escape from them

Learning

• Classical conditioning occurs when an animal makes a mental connection between a stimulus and some kid of good or bad event– Pavlov’s dogs

• Operant conditioning is sometimes called trial-and-error learning– An animal learns to behave in a certain way in order

to receive a reward or avoid punishment• EXAMPLE

– A predator learns not to eat a particular prey in order to avoid an unpleasant experience

Learning

• In insight learning, an animal applies something it has already learned to a new situation – without a period of trial-and-error

– Rare among most animals– Common only in primates

Instinct and Learning Combined

• Some behaviors cannot occur without some learning on the part of the animal

• For example, newborn ducks and geese have a built-in urge to follow their mother

• But this instinct to follow does not include a picture of what their mother looks like

• This picture must be provided by experience in a process called imprinting– The newborn bird will follow the first large

slowly moving object it sees

Chapter 35: Animal Behavior

Section 2: Communication: Signals for Survival

Communication: Signals for Survival

• Any time animal behavior involves more than one individual, some form of communication is involved

• Communication is the passing of information from one animal to another

• Animals use many varied techniques to communicate with one another

Sensing the Natural World

• No two animal species sense the world in the same way

• Each animal species has a unique way of gathering and transmitting information

• Understanding the differences between our sensory world and that of animals is important in the study of animal behavior

• Today, many scientists study animals under natural conditions– Ethologists

Why Animals Communicate

• Animals communicate with one another for a variety of reasons

– Courtship behavior

– Food

– Potential dangers

How Animals Communicate

• Animals communicate with other members of their species and with other species

• The ways in which they communicate are limited only by the kinds of stimuli their senses can detect– Visual signals

• Movement and color– Sound signals– Chemical signals

• Well-developed sense of smell• Produce special chemicals called pheromones that

transmit information– Electrical signals

Language

• Some forms of animal communication are more complicated than any of the signals just described

– Animal “dances”

• Human language is the most complicated form of communication

Chapter 35: Animal Behavior

Section 3: The Evolution of Behavior

The Evolution of Behavior

• The physical structures in organisms develop according to a program contained in their DNA

• Different characteristics are coded in different genes or groups of genes

• Variations in these genes lead to inheritable variations in the characteristics of the animals that carry them

The Evolution of Behavior

• Genes code for behaviors as well as for physical characteristics

• Evidence for genetic control of behavior can be demonstrated by crossing closely related animals that show different behaviors

• The evolutionary fitness of an individual is increased if it forms some type of social group with others of its kind