a. By watching animals, such as the heron in Figure 49.1, we can catalog a repertoire of behaviors.

b. Ethology is the biological science of behavior, and it attempts to answer a variety of questions about stimuli, learning, rituals, maturation processes, consciousness, and intelligence.

c. Anthropomorphism is practiced by making it appear that nonhuman animals have human-like thoughts and feelings.

d. Behavior includes all of an animal's overt, observable activities, including fighting, avoiding fights, searching for food and feeding, courtship and mating, and communication activities.

e. Ethological research was pioneered by Charles Whitman and Oskar Heinroth early in the twentieth century, and was further developed by Nikolaas Tinbergen and Konrad Lorenz.

f. Many conclusions about animal behavior are based on observations of vertebrates, especially birds.

a. Through natural selection, species evolve successful strategies for survival.

b. A strategy that does not result in success will not be retained, as the animal using it is unlikely to live or reproduce.

c. Much of an organism's activity consists of internal physiological events, affecting no one but itself.

d. However, each surviving organism is a competitor for resources.

e. Behavior therefore involves one individual winning at the expense of another.

f. A central question is whether a particular behavioral pattern is an evolutionarily stable strategy (ESS) that the animal can maintain against the counter-behaviors of others.

g. Simple game theory can be used to analyze behavior patterns, as win and loss values can be assigned to an animal's options in various situations.

h. Game theory can also be applied to a population of animals.

i. A hawk (aggressive), dove (peaceful) example illustrates the use of game theory and numerically evaluating various behavioral options (Figure 49.2).

j. The advantages of one behavior over another, as in the hawk/dove example, depends on the makeup of the population.

k. The points assigned to interactions in these analyses measure the time and energy an animal gains or loses from certain behaviors.

l. The ultimate payoff for an animal is the ability to reproduce.

a. Instinct is useful as a general term for genetically determined, species-specific patterns of behavior.

b. For the majority of animals, the genetic programs governing physiological processes also govern behavior; thus their behaviors are almost entirely instinctive.

c. If learning is defined as modification of an animal's behavior on the basis of its experiences, then learning plays only a minor role in the behavior of most species.

d. The problem of separating learned behaviors from instinctive ones is complicated by the question of maturation.

e. Some behaviors (e.g. sexual behaviors) develop without any need for practice or for environmental input.

f. Some animals learn complex behaviors from their parents, and there is a broad range of behaviors that require specific environmental inputs, called imprinting.

g. Some behaviors (e.g. flying) are genetically encoded but require practice as the animal matures.

h. A behavior that changes can be called maturation if changing the reward time does not affect the behavior as it would in the case of learning (e.g. the cuttlefish behavior illustrated in Figure 49.3).

i. It has been postulated that animals have certain physiologically based drives that cause their behaviors; hunger is a drive that motivates an animal to search for food.

a. A fixed-action pattern is a highly stereotyped, genetically encoded action that an animal does not learn.

b. An animal refines a fixed-action pattern through directing or orienting movements called taxes (singular taxis).

c. The distinction between fixed-action patterns and taxes is illustrated by Lorenz and Tinbergen's study of the Greylag Goose (Figure 49.4), which finishes egg-retrieving actions even when the object egg has been removed.

d. A fixed-action pattern is only performed at certain times, and any stimulus that sets it off is a releaser, sometimes called a sign stimulus.

e. The releaser for goose egg-retrieving behavior is the presence of an egg (or, a rock, or a ball that looks like an egg) near the nest; this sets off a fixed-action pattern that cannot be stopped until it is completed.

f. To explain fixed-action patterns, an innate releasing mechanism (IRM) has been postulated as a stimulus filter that selectively directs the animal's attention to a releasing stimulus and then initiates the appropriate action.

g. The model in Figure 49.5 outlines several animal behavior postulates.

a. Studies of several species of digger wasps illustrate that many fixed-action patterns are involved in the complex process of digging a burrow, finding and killing a specific type of prey, moving the prey to the burrow, checking the burrow, moving the prey into the burrow, laying an egg on the prey, and closing the burrow (Figure 49.6).

b. Tinbergen and Kruyt showed that the wasp's ability to find its burrow, upon returning with prey, depends on its memorization of visual clues (Figure 49.7).

c. Two African lovebird species (Figure 49.8) have different mechanisms for carrying nest materials, and hybrids between the two are generally confused as they attempt to use both mechanisms but are not very efficient at it.

d. Thus, many activities are genetically based functional adaptations that become confused and ill-adapted in hybrid organisms.

a. A releaser is something in the environment that is selected out of a background of possible stimuli by an innate releasing mechanism.

b. Male sticklebacks (Figure 49.9) have bright red bellies and show aggression toward other fish with red bellies, and other things (e.g. a flower petal) that are red, but not toward realistic fish models that have no red.

c. A releaser is a sign stimulus when it is a specific morphological feature that appears to have evolved only to trigger a behavior.

d. Even if animals waste some time and energy responding to false signals, the system is generally adaptive and well-designed for success.

e. Bird chicks will open their mouths to eat upon seeing either an adult or a model of the appropriate size (Figure 49.10) at their nest, showing the importance of sign stimuli.

f. Adult birds feeding their young will also attempt to feed models of the appropriate color and size; the chick that opens the widest gets the most food, but one that does not open its mouth is a releaser for the adult to roll it out of the nest, as if it were dead.

g. Protective mimicry is an example of a releaser involving sign stimuli from animal shapes, colors, and movements (Figure 49.11).

a. Most animal behavior is directed toward some final act–drinking, eating, or mating–and is set off by releasers.

b. An animal can rarely merely perform the final act, but first must perform certain preliminary activities.

c. An activity begins with appetitive behavior, wide, searching actions that bring the animal into contact with specific releasers that set off the next phase of activity.

d. An animal that searches for prey to eat may go through a series of actions that involve searching, chasing, and pouncing; eating the prey is a consummatory behavior.

e. Stickleback mating behavior illustrates a pattern of activities directed toward the final mating act.

f. To account for such step by step behaviors, Tinbergen postulated a hierarchical organization of behavior, with a series of innate releasing mechanisms arranged so that each one leads to the next (Figure 49.12).

a. Complex behavior patterns have evolved as chains of smaller fixed behaviors in which the completion of one act, with the resulting internal and external conditions, sets off the next act.

b. In studies of the stickleback, Tinbergen identified a pattern of courtship actions leading to fertilization (Figure 49.13).

c. This pattern of actions involved two members of the opposite sex stimulating various actions in each other, creating a chain of stimuli and responses, and ultimately resulting in spawning, egg fertilization, and protection of developing young.

a. Some behavior patterns develop fully with maturation or practice and require no special input of information.

b. Other fixed-action patterns require the input of additional information through the process of imprinting, as illustrated by Lorenz's experiment with Greylag goslings that hatched in his laboratory (Figure 49.14).

c. Imprinting underlies many animal behaviors, such as the homing behavior of salmon, whose return to the correct home stream has been shown to depend on their olfactory sense.

d. Behavioral patterns that require imprinting are important in both reproduction and social coherence.

e. Imprinting systems should evolve whenever the general outline of a needed behavior is clear and inheritable but the details are too unpredictable or complex to be genetically encoded.

f. The development of bird song shows the role of both maturation and imprinting.

g. Peter Marler and M. Tamura studied the singing patterns of White-crowned Sparrows (Figure 49.15), and found there is a critical time in the life of a juvenile bird when it must be exposed to the proper song if it is to sing properly at maturity.

h. Imprinting must occur at a critical period in the animal's development, and if the proper stimulus is not present during this period, the behavior remains incomplete.

a. Learning means an enduring change in behavior as a result of experience, and not simply due to maturation.

b. Learning confers a selective advantage by giving animals a wider range of options than could be encoded by the genetic appartus alone.

c. Each genetic feedback loop takes at least a generation to show results, and many generations are needed to shape a behavior.

d. Learning, however, operates with a very short feedback loop that may take only seconds or minutes, as an animal receives immediate confirmation of success or failure.

e. The simplest learning is habituation, where animals learn to ignore constant or persistent stimuli.

f. Animals that normally react with alarm to certain signals (e.g. chickens reacting to the shape of a hawk) can become habituated to the signal if it is presented repeatedly without harming them.

g. Complex learning requires insight, concept formation, and language.

h. Some animals can learn new paths to food when a previously learned path is blocked.

i. Some birds and mammals can develop an abstract conception of number.

j. Wolfgang Kohler performed experiments during the 1920s that demonstrated chimpanzees' abilities to solve problems.

k. Jane Goodall showed that chimps, in their native habitats, commonly use tools to get food.

l. The ability to learn beyond simple habituation is the exception among animals, and we understand little about what happens when an animal learns.

a. Conditioning is a simple type of learning that strengthens the association between a stimulus and a response.

b. Classical, or respondent, conditioning was described by Ivan Pavlov, who conditioned a dog to salivate at the sound of a bell (Figure 49.16).

c. In classical terminology, the food is an unconditioned stimulus and the salivation an unconditioned response, but in our terminology they are a releaser and a fixed-action pattern (Figure 49.16).

d. Once the bell is associated with salivation, its sound becomes a conditioned stimulus and salivation a conditioned response.

e. That is, a conditioned stimulus associated with a releaser takes on the force of the releaser and can evoke the fixed-action pattern by itself.

f. Learning occurs if the conditioned stimulus and the natural releaser are presented together or if the stimulus precedes the releaser by a short interval; no conditioning occurs if the stimulus follows the releaser.

g. Operant, or instrumental, conditioning is best explained by an example involving a pigeon learning to select a lighted key, from among several available, in order to receive food (Figure 49.17).

h. The pigeon is initially confronted by many stimuli, and the lighted key is the discriminative stimulus that causes the pigeon's behavior to be rewarded.

i. The reward reinforces the desired behavior of the animal.

j. Conditioned behavior has been shown to be strengthened more by intermittent reinforcement than by continual reinforcement.

k. Both classical and operant conditioning are subject to extinction: If the reinforcement stops, the learned behavior diminishes in frequency and eventually dies out.

l. Both types of performance increase with the number of reinforced trials and decrease with the number of nonreinforced trials.

m. Both types are subject to stimulus generalization; a pigeon conditioned to peck at a specific light will also peck at lights of longer or shorter wavelengths according to a rather neat curve (Figure 49.18).

n. Recent studies of fruit fly behavior have shown that general signal-transduction pathways are involved in both hormone responses and learning.

a. The African honeyguide is a bird that used to engage in behavior that guided humans and Ratels (Figure 49.19) to honeybee hives, and the bird made use of the opened hive by feeding on dead bees and pieces of wax.

b. As civilization has encroached on its habitat, and honey was made available in local stores, humans have less frequently engaged in behavior reinforcing the honeyguide's guiding habit, and the behavior has completely died out in some areas.

c. Animals do have traditions and can learn from one another.

d. Oystercatchers are large shorebirds that feed on clams and mussels (Figure 49.20), and they learn, rather than inherit, just one of two ways (hammering or stabbing) to open the shells of their prey.

a. Animals can orient themselves with regard to fixed points such as nests, breeding grounds, or sources of food.

b. Ants use a chemical signal to mark trails to food with a pheromone (Figure 49.21).

c. The migration of animals, such as whales, bats, caribou, butterflies, and birds (Figure 49.22), is only recently being understood.

d. The motive force behind birds beginning a migration lies in day length and photoperiod.

e. Migration must have evolved independently in many species, and it is now clear that birds rely on a variety of directional cues in establishing a route of travel.

f. Hooded crows have been shown to migrate generally by direction (Figure 49.23), others use visual cues from the positions of the sun and stars (Figure 49.24) or from landmarks.

g. Internal clocks are an important component of the orientation mechanisms in birds, and those whose clocks have been shifted alter their direction of travel.

h. The earth's magnetic field is also used for bird orientation, as shown by experiments involving changing the field around a bird.