Chapter 51: Animal Behavior

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Chapter 51: Animal Behavior


• Humans have probably studied animal behavior for as long as we have lived on Earth

• As hunters knowledge of animal behavior was essential to human survival


• Cranes are birds that have captivated people’s interest

– Possibly because they are large and their behavior is easily observed

Figure 51.1


What Is Behavior?

• What an animal does and how it does it

• Includes muscular and nonmuscular activity

Figure 51.2

Dorsal fin

Anal fin


• Learning

– considered a behavioral process


• Proximate, or “how,” questions

– Focus on the environmental stimuli that trigger a behavior

– Focus on the genetic, physiological, and anatomical mechanisms underlying behavior


• Ultimate, or “why,” questions about behavior

– Address the evolutionary significance of a behavior


Ethology: Scientific study of animal behavior


Fixed Action Patterns (FAP)

• Sequence of unlearned, innate behaviors that is unchangeable

• Once initiated, is usually carried to completion

• Triggered by an external sensory stimulus

– (sign stimulus)


• In male stickleback fish, the stimulus for attack behavior

– Is the red underside of an intruder

Figure 51.3a

(a) A male three-spined stickleback fish shows its red underside.


• As long as some red is present in a model, the attack behavior occurs

Figure 51.3b

(b) The realistic model at the top, without a red underside, produces no aggressive response in a male The realistic model at the top, without a red underside, produces no aggressive response in a male three-spined stickleback fish. Thethree-spined stickleback fish. Theother models, with red undersides, produce strong responses.other models, with red undersides, produce strong responses.


• Proximate and ultimate causes for the FAP attack behavior in male stickleback fish

Figure 51.4

ULTIMATE CAUSE: By chasing away other male sticklebacks, a male decreasesthe chance that eggs laid in his nesting territory will be fertilized by another male.

BEHAVIOR: A male stickleback fish attacks other male sticklebacks that invade its nesting territory.

PROXIMATE CAUSE: The red belly of the intruding male acts as a sign stimulusthat releases aggression in a male stickleback.


Imprinting

• Behavior with both learning and innate components and is generally irreversible

• Sensitive period

– limited phase that is only time when certain behaviors can be learned


• Konrad Lorenz showed that

– When baby geese spent the first few hours of their life with him, they imprinted on him as their parent


• There are proximate and ultimate causes for this type of behavior

Figure 51.5

BEHAVIOR: Young geese follow and imprint on their mother.

PROXIMATE CAUSE: During an early, critical developmental stage, the young geese observe their mother moving away from them and calling.

ULTIMATE CAUSE: On average, geese that follow and imprint on their mother receive more care and learn necessary skills, and thus have a greater chance of surviving than those that do not follow their mother.


• Program to save the whooping crane from extinction

Figure 51.6


• Biologists study the ways both genes and the environment

– Both influence the development

• Behavior that is developmentally fixed is called innate behavior, under strong genetic influence


Kinesis

• Simple change in activity or turning rate in response to a stimulus


• Sow bugs

– Become more active in dry areas and less active in humid areas

Figure 51.7a

Dry open areaMoist site under leaf

(a) Kinesis increases the chance that a sow bug will encounter and stay in a moist environment.


Taxis

• Automatic, oriented movement toward or away from a stimulus


• Fish exhibit positive rheotaxis

– automatically swim in an upstream direction

Figure 51.7b

Direction

of river

current

(b) Positive rheotaxis keeps trout facing into the current, the direction from which most food comes.


Migration

• Genetically programmed

Figure 51.8


Animal Signals and Communication

• Signal behavior that causes a change in another animal’s behavior

• Communication reception of and response to signals


• Animals communicate using

– Visual, auditory, chemical, tactile, and electrical signals


Chemical Communication

• Pheromones


• When a minnow or catfish is injured

– An alarm substance in the fish’s skin disperses in the water, inducing a fright response among fish in the area

Figure 51.9a, b

(a) Minnows are widely dispersed in an aquarium before an alarm substance is introduced.

(b) Within seconds of the alarm substance being introduced, minnows aggregate near thebottom of the aquarium and reduce their movement.


Auditory Communication

• Insect courtship songs (under genetic control) Charles Henry, Lucía Martínez, and ent Holsinger crossed males and females of Chrysoperla plorabunda and Chrysoperla johnsoni, two

morphologically identical species of lacewings that sing different courtship songs.

EXPERIMENT

SONOGRAMS Chrysoperla plorabunda parent

Vibration volleys

Standard repeating unit

Chrysoperla johnsoni parent Volley period

crossed with

Standard repeating unit

The researchers recorded and compared the songs of the male and female parents with those of the hybrid offspring that had been raised in isolation from other lacewings.

Volley period


Learning

• Modification of behavior based on specific experiences


Habituation

• Loss of responsiveness to stimuli that convey little or no information


Spatial Learning

• Modification of behavior based on experience with the spatial structure of the environment


• Classic experiment

– Showed how digger wasps use landmarks to find the entrances to their nests

After the mother visited the nest and flew away, Tinbergen moved the pinecones a few feet to one side of the nest.

Figure 51.14CONCLUSION

A female digger wasp excavates and cares for four or five separate underground nests, flying to each nest daily with food for the single larva in the nest. To test his hypothesis that the wasp uses visual landmarks to locate the nests, Niko Tinbergen marked one nest with a ring of pinecones.

EXPERIMENT

Nest

When the wasp returned, she flew to the center of the pinecone circle instead of to the nearby nest. Repeating the experiment with many wasps, Tinbergen obtained the same results.

RESULTS

The experiment supported the hypothesis

that digger wasps use landmarks to keep track of their nests.

NestNo Nest


• Classical conditioning

– Arbitrary stimulus is associated with a reward or punishment

Figure 51.15

Before stimulus

Influx of water alone

Influx of alarm substances

Influx of pike odor

Day 1 Day 3

Control group

Control group

Experimentalgroup

Experimental group

Rel

ativ

e a

ctiv

ity le

vel


Classical conditioning



• Operant conditioning

– Animal learns to associate one of its behaviors with a reward or punishment, trial and error learning

Figure 51.16


Cognition and Problem Solving

• Perceive, store, process, and use information gathered by sensory receptors


• Problem solving can be learned

– By observing the behavior of other animals

Figure 51.17


Variation in Prey Selection

• Due to prey availability and are evidence of behavioral evolution

Figure 51.18a, b

(a) A garter snake (Thamnophis elegans)

(b) A banana slug (Ariolimus californicus); not to scale


Variation in Aggressive Behavior

• Funnel spiders living in different habitats

– Exhibit differing degrees of aggressiveness in defense and foraging behavior

Figure 51.19

50

40

30

20

10

0

Tim

e to

atta

ck (

seco

nds)

Field Lab-raised generation 1

Lab-raised generation 2

Desert grassland population

Riparian population

60

Population


• Migratory orientation of wintering adult birds captured in Britain

• Evolution of behavior

Figure 51.21b

(b) Wintering blackcaps captured in Britain and their laboratory-raised offspring had a migratory orientation toward the west, whileyoung birds from Germany were oriented toward the southwest.

N

E

S

WAdults from Britain and F1

offspring of British adults

N

E

S

WYoungfrom SW Germany

Mediterranean Sea

BRITAIN

GERMANY


• Natural selection favors behaviors that increase survival and reproductive success


Foraging Behavior

• Optimal foraging theory

– Views foraging behavior as a compromise between the benefits of nutrition and the costs of obtaining food


• Bluegill sunfish

– Prey selection behavior is related to prey density

Figure 51.23

Low prey density High prey density

33%33%33%

32.5%32.5%35%

2%40%

57%

100%

50%35%

14%

33%33%33%

Small preyMedium preyLarge prey



Percentage available

Predicted percentage in diet

Observed percentage in diet

Large prey at far distance

Small prey at middle distance

Small prey at close distance


Mating Behavior and Mate Choice

• Product of a form of natural selection call sexual selection


• Species w/ large numbers of offspring

– Parental care carried out by males or females

Figure 51.26

Eggs


• Mate Choice by Females

• e.g. Male zebra finches more ornate than females, affects mate choice by the females

Figure 51.27


• Male comp. for mates

– often ritualized contest

Figure 51.30


• Many social behaviors are selfish

• Natural selection favors behavior

– That maximizes an individual’s survival and reproduction


Altruism

• Behavior that reduces an individuals fitness but increase the fitness of others


• Naked mole rat populations

– Nonreproductive individuals may sacrifice their lives protecting the reproductive individuals from predators

Figure 51.33


• 3 variables in an altruistic act are

– The benefit to the recipient

– The cost to the altruist

– The coefficient of relatedness


Reciprocal Altruism

• Altruistic behavior toward unrelated individuals, aided individual returns the favor in the future


Kin Selection

• Inclusive fitness, behavior that favors reproductive success of relatives

• Explains altruistic behavior between related individuals


Social Learning of Alarm Calls

• Infant monkeys give undiscriminating alarm calls at first

– But learn to fine-tune them by the time they are adults

Figure 51.37


• No other species

– Comes close to matching the social learning and cultural transmission that occurs among humans

Figure 51.38

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Chapter 51: Animal Behavior