--------------Intro to Animal Behavior--------------Behavior is action that alters the relationship between an organism and its environment. Behavior may occur as a result of external stimuli (e.g., sight of a predator), internal stimuli (e.g., hunger) or a mixture of the two (e.g., mating behavior: sight of a mate and the urge to mate). The study of animal behavior involves investigating the relationships animals have with their physical environments and with other organisms. Examples of animal behavior studies could include research to determine how animals find and defend resources, communicate, avoid predators, choose mates, reproduce and care for their young.

It is often useful to distinguish between Innate behavior: Behavior determined by the "hard-wiring" of the nervous system. It is usually

inflexible, a given stimulus triggering a given response. A salamander raised away from water until long after its siblings begin swimming successfully will swim every bit as well as they the very first time it is placed in the water. Clearly this rather elaborate response is "built in" in the species and not something that must be acquired by practice.

Learned behavior: Behavior that is more or less permanently altered as a result of the experience of theindividual organism (e.g., learning to play baseball well).

However, careful analysis often reveals that any particular behavior is a combination of innate and learned components.

When studying behavior, it is important to identify both the behavior and the related stimulus (internal or external) that initiates or controls it. Ultimately, this leads us to ask why the behavior exists, and what evolutionary significance it might have (for example, how did it influence the species' survival and reproductivesuccess?).

--------------------Innate Behavior--------------------Types of innate behavior: Taxes, Reflexes, Instincts

Reflexes Reflexes will not be discussed in detail here, but they are automatic, involuntary nervous responses to stimuli involving one body part (for example, pulling a hand away from a hot stove).

TaxesSome organisms respond to a stimulus by automatically moving directly toward or away from or at some

defined angle to it. These responses are called taxes. They are similar to tropisms in plants except that actual locomotion of the entire organism is involved.

Chemotaxis: Responding to chemical compounds Phototaxis: Responding to light Magnetotaxis: Responding to magnetic fields

InstinctsInstincts are complex behavior patterns that are inborn, inflexible

and valuable at adapting the animal to its environment. They differ fromreflexes in their complexity. The entire body participates in instinctivebehavior, and an elaborate series of actions may be involved.

The scratching behavior of a dog and a European bullfinch,shown here, is part of their genetic heritage. The widespread behavior ofscratching with a hind limb crossed over a forelimb in common to mostbirds, reptiles, and mammals. Instincts are inherited just as the structureof tissues and organs are.

Drawing courtesy of Rudolf Freundand Scientific American, 1958

Another example: The African peach-faced lovebird carries nesting materials to the nesting site by tucking them

underneath their wings. Its close relative, the Fischer's lovebird, uses its beak to transport nesting materials. The two species can breed with one another. When they do so, the offspring try to tuck the nesting

materials under their wings, which they are incapable of doing due to the shape of the wing. After they fail at tucking a few times, they carry nesting material in their beaks.

Foraging BehaviorForaging for food is a crucial behavior for animals. Like all behavior, it requires the interaction of many

components. Nonetheless, it turns out that in some animals, at least, foraging behavior can be altered by a singlegene.

Foraging Behavior in Drosophila melanogaster (fruit flies)The discovery of the genetic control of foraging in Drosophila began with the observations of Marla

Sokolowski when she was an undergraduate biology student at the University of Toronto. She noticed that Drosophila larvae, feeding in her culture vessels, displayed one of two distinct feeding patterns:

rovers, who moved rapidly over the surface of the culture medium sitters, who fed at a much more leisurely pace

She went on to find that this pattern of behavior continued when the larvae became adults was present in populations of wild fruit flies, not just in her laboratory colonies

After further years of research, she has shown that the behavior is under the control of a single gene, named for ("foraging"). There are two alleles present in the population at almost equal frequencies.

forR, which is dominant [rovers are either homozygous (forR/forR) or heterozygous (forR/fors)] fors, which is recessive [sitters are homozygous (fors/fors)] About 70% of natural populations are rovers

Both alleles encode a PKG, an enzyme that attaches phosphate groups to proteins. The enzyme encoded by the forR allele is more active than that encoded by fors. PKG is activated by a molecule called cyclic GMP (cGMP).She and her colleagues have succeeded in inserting forR DNA into sitters who promptly become rovers.

Why should alleles for two such different behaviors be maintained at such high frequency in the population? One possible answer: it permits the population to thrive under varying food conditions:

sitters are favored when food is abundant; rovers are favored when competition for food is strong, such as in crowded cultures.

Honeybees ( Apis mellifera)Honeybees have their version of the for gene, called Amfor ("Apis mellifera for"). It, too, encodes the

cGMP-dependent protein, PKG. When worker bees first hatch, they remain in the hive tending to various housekeeping chores, such as

feeding the larvae. But when they are 2–3 weeks old, they leave the hive and begin foraging for nectar and pollen. This change in behavior coincides with the increased expression of Amfor. When newly-hatched workers are treated with cGMP, the amount of PKG in their brains goes up and they quickly begin foraging instead of doing housekeeping.

Releasers of Instinctive BehaviorSo once the body is prepared for certain types of instinctive behavior, an

external stimulus may be needed to initiate the response. The stimulus need notnecessarily be appropriate to be effective. During the breeding season, the female three-spined stickleback normally

follows the red-bellied male (a in the figure) to the nest that he has prepared. He guides her into the nest (b) and then prods the base of her tail (c). She then lays eggs in the nest. After doing so, the male drives her from the nest, enters it himself, and

fertilizes the eggs (d). Although this is the normal pattern, the female will follow almost any small

red object to the nest, and once within the nest, neither the male nor anyother red object need be present.

Any object touching her near the base of her tail will cause her to release hereggs.

It is as though she were primed internally for each item of behavior and neededonly one specific signal to release the behavior pattern. For this reason, signalsthat trigger instinctive acts are called releasers. Once a particular response isreleased, it usually runs to completion even though the stimulus has beenremoved. One or two prods at the base of her tail will release the entire sequenceof muscular actions involved in liberating her eggs.

Pheromones (chemical signals) serve as important releasers for the socialinsects: ants, bees, and termites. Many of these animals emit several different pheromones which elicit, for example, alarm behavior, mating behavior, and foraging behavior in other members of their species. The mammary glands of domestic rabbit mothers emit a pheromone that releases immediate nursing behavior by their babies. A good thing, too, as mothers devote only 5-7 minutes a day to feeding their pups so they had better be quick about it.

A number of studies have shown that animals can often be induced to respond to inappropriate releasers. For example, a male robin defending its territory will repeatedly attack a simple clump of red feathers but will not attack a stuffed robin that lacks the red breast of the males. Although such behavior seems inappropriate to our eyes, it reveals a crucial feature of all animal behavior: animals respond selectively to certain aspects of thetotal sensory input they receive. Animals spend their lives bombarded by lots of sights, sounds, odors, etc. But their nervous system filters this mass of data, and they respond only to those aspects that the evolutionary history of the species has proved to be significant for survival.

Other Types of Instinctive BehaviorMigrationMigration is the periodic movement of an animal from the place where it has been living to a new area and its subsequent return journey to the original home. When animals migrate, it is usually to find abundant food and a good place to breed.

HibernationHibernation is a time of inactivity in order to help an animal survive through the cold winter months. This inactivity is not like human sleep where loud noises can wake you up. With true hibernation, the animal can be moved around or touched and not know it.

EstivationEstivation is a state of dormancy similar to hibernation, but during the months of the summer. Animals that estivate spend a summer inactive and insulated against heat and dryness to avoid the potentially harmful effects of the season, or to avoid contact with other species with which they may otherwise be in competition, or for which they are prey.

--------------------Learned Behavior--------------------HabituationHabituation is a reduction in a previously-displayed response when no reward or punishment follows. If you make an unusual sound in the presence of the family dog, it will respond — usually by turning its head toward the sound. If the stimulus is given repeatedly and nothing either pleasant or unpleasant happens to the dog, it will soon cease to respond. This lack of response is not a result of fatigue nor of sensory adaptation (an example of sensory adaptation is if someone rests their hand on a table, they immediately feels the table's surface on their skin. Within a few seconds, however, they cease to feel the table's surface. The sensory neurons stimulated by the table's surface respond immediately, but then respond less and less until they may not respond at all). Habituation is long-lasting; when fully habituated, the dog will not respond to the stimulus even though weeks or months have elapsed since it was last presented.

SensitizationSensitization is an increase in the response to aninnocuous stimulus when that stimulus occurs after apunishing stimulus. An example: When the siphon of the sea slug Aplysia is gentlytouched, the animal withdraws its gill for a brief period(1st bar). However, if the tail receives an electricalshock beforehand, the same gentle touch to the siphonwill elicit a longer period of withdrawal (not shown).The sensitization response to a single shock dies outafter about an hour (2nd bar), and returns to baselineafter a day (3rd bar). So it is an example of short-termmemory. However, if the animal is sensitized with multipleshocks given over several days, its subsequent responseto a gentle touch on the siphon is much larger and isretained longer (4th & 5th bars). This is an example oflong-term memory and requires protein synthesis.

ImprintingIf newly-hatched geese are exposed to a moving object of reasonable sizeand emitting reasonable sounds, they will begin to follow it just as theywould normally follow their mother. This is called imprinting. The time of exposure is quite critical. A few days after hatching,imprinting no longer occurs. Prior to this time, though, the results can bequite remarkable. A gosling imprinted to a moving box or clucking personwill try to follow this object for the rest of its life. In fact, when thegosling reaches sexual maturity, it will make the imprinted object, ratherthan a member of its own species, the goal of its sexual drive. Much of our knowledge of imprinting was learned from the research ofKonrad Lorenz, shown here with some of his imprinted goslings. Lorenzshared a Nobel Prize in 1973 for his discoveries. Male mice become imprinted with the odor of litter-mates during the firstthree weeks of life. When they reach sexual maturity, they avoid matingwith close relatives.

The Conditioned Response (CR)The conditioned response is probably the simplest form of learned behavior. It is a response that, as a result of experience, comes to be caused by a stimulus different from the one that originally triggered it. The Russian physiologist Ivan Pavlov found that placing meat powder in a dog's mouth would cause it to salivate. The meat powder, an unconditioned stimulus (US), triggers a simple inborn reflex involving taste receptors, sensory neurons, networks of interneurons in the brain, and autonomic motor neurons running to the salivary glands producing an unconditioned response (UR). Pavlov found that if he rang a bell every time he put the meat powder in the dog's mouth, the dog eventually salivated upon hearing the bell alone. This is the conditioned response (CR). The dog has learned to respond toa substitute stimulus, the conditioned stimulus (CS). We assume that the physiological basis of the conditioned response is the transfer, by appropriate neurons, of nervous activity in the auditory areas of the brain to the motor neurons controlling salivation. This involves the development and/or strengthening of neural circuits, which, we may also assume, is characteristic of all forms of learning. The conditioned response has proven to be an excellent tool for determining the sensory capabilities of other animals. For example, honeybees can be conditioned to seek food on a piece of blue cardboard . By offering other colors to a blue-conditioned bee, Karl von Frisch (who shared the 1973 Nobel Prize with Lorenz) found that honeybees can discriminate between different colors.

Instrumental ConditioningPavlov's dogs were retrained and the response being conditioned (salivation) was innate. But the principles of conditioning can also be used to train animals to perform tasks that are not innate. In these cases, the animal is placed in a setting where it can move about and engage in different activities. The experimenter chooses to reward only one behavior, for example, turning to the left. By first rewarding (witha pellet of food) even the slightestmovement to the left and then only morecomplete turns, a skilled experimenter canin about 2 minutes train a pigeon to makea complete turn. A little more work and thepigeon will pace out a figure eight. In the example shown here, the pigeon,presented with two spots of light, pecks atthe brighter and reaches down to pick up the grain of food that is its reward. Such training is known as instrumental conditioning or operant conditioning. The latter term was coined by B. F. Skinner, whose skill with the technique enabled him to train pigeons to play ping-pong and even a toy piano!

It is also called trial-and-error learning because the animal is free to try various responses before finding the one that is rewarded.

Maze problems are a form of instrumentalconditioning in which the animal is faced with asequence of alternatives. In this photo, Julia, a chimpanzee, uses a magnetto move an iron ring through a maze. Julia is ableto solve mazes like this on her first attempt most(86%) of the time and sometimes faster thanbiology students can.

ConceptsAlthough most animals solve mazes and other problems bytrial and error, Julia (and biology students) usually make onlyone or two random attempts at solving a problem and then, allof a sudden, "get it." They have made an abstractgeneralization about the specific problem; that is, have formeda concept.Oddity problems are an example. This young rhesus monkeyhas learned that food will be found, not under any particularobject, but under whichever object is different from the others.In monkeys (and probably humans as well), concept formationdepends on activity in the prefrontal cortex of the brain.Recent research suggests that honeybees can also solve simpleoddity problems.

---------------------Social Behavior---------------------Social animals such as chimpanzees have a complex system of communicating and functioning in their groups and scientists have shown chimpanzees display social behavior that is both innate and learned. Chimpanzees areintelligent enough to adapt and learn not only from their own species, but from other animals in their habitat. Because of this fluidity of influencing what chimpanzees observe and can learn from, many times their behaviorare learned from observing other animals (for example, searching for food sources). However, animals such as ants or bees are usually more genetically “hard-wired”, and their interactions with other members of their species can only evolve to a certain level of sophistication to serve their purpose (such as bee-dancing to communicate with each other about a food source).

Patterns of BehaviorSocial behaviors in animals can be related to courtship and mating, caring for young, defense, obtaining food, establishing or maintaining territory or periodic cycles. Successful behaviors promote survival of the individual animal and its future generations.

Courtship consists of behaviors that help members of the same species identify and select potential mates. Sexual selection is an evolutionary mechanism in which some traits increase an individual's chance of mating and passing along its genetic information.

Parental care, if present, is usually provided by the female. This may allow successful and perhaps healthier males to maximize their reproductive output. Reproduction and care of offspring requires a great deal of energy, and the number of offspring produced at any one time is usually inversely proportional to the amount of energy invested in parental care (meaning if a lot of offspring are produced, little energy is invested in parental care; if few offspring are produced, a lot of energy is invested in parental care).

Defensive behaviors involve protection of the individual. In some animals, it also involves protection ofoffspring, mates and territory.

Migration is the regular, recurrent, seasonal movement of populations from one geographic location to another and back again. Many species of fish, mammals, and even insects take amazing migratory journeys, but birds, as a group, are the most mobile creatures on Earth. In general, migrating animals useone or more of three mechanisms: piloting, orientation and navigation. Piloting involves use of familiar landmarks and usually is used to locate nearby destinations. In orientation, an animal detects compass directions and travels in straight-line pathways. Navigation, which is the most complex mechanism, involves being able to determine the present location, and then the use of compass direction to travel in the desired direction. Some animals use the Earth's magnetic field, the sun, or the stars for navigation.

Foraging behaviors relate to the ability of the animal to locate, obtain and consume food.

Many animals respond to periodic changes in the environment with daily or seasonal cycles of behavior. Daily patterns, such as sleep cycles, are referred to as circadian rhythms and are related to the Earth's 24 hour day-night cycles. Other periodic behavior can be linked to changes in the length of day and night, or of temperature.

Territorial behavior typically relates to feeding, mating and/or caring for offspring. A territory can varywidely from species to species. Territorial behavior is thought to lead to increased reproductive success by defending a particular area containing critical resources.

Example: Siamese Fighting Fish (Betta splendens) AKA Betta fish Male Betta fish are extremely aggressive towards males of their own species (though they

are total wimps when attacked by a different species), and will readily fight to complete exhaustion. When fighting, males will nip at each others fins until one of them is too tiredto continue, though this usually takes so long that the fins of both combatants resemble torn up rags by the time one of the fish concedes defeat by retreating.

Male Betta fish will fight to claim territory, or to protect their eggs or protect their offspring, but physical combat is always preceded by a display sometimes called "flaring." When stimulated by the sight of a rival male (the releaser), a male Betta fish will exhibit several types of genetically determined aggressive movements. The fish will spread his fins, extend his gill opercula and membranes, and generally appear much largerthan his resting size. If this does not cause the rival male to retreat, fighting will ensue.

Communication Communication occurs when one organism passes along some type of information (signal) to another, generating a response. Animals may use visual, auditory (sound), tactile (touch), chemical or electrical signals to communicate with one another. Transmitting and receiving these signals generates an external or internal response in the organism. Some examples are:

Pheromones, chemical signals used for communication, are especially common in mammals and insects.Bees use pheromones to determine social rank and to initiate reproduction. The context of the signal is important. For example, male honeybees will respond to the pheromones of the queen while they are outside the hive (where they can mate), but are unaffected by the pheromones while inside the hive. Antsalso use pheromones to mark a trails to food sources.

Karl von Frisch was awarded the Nobel Prize for physiology and medicine in 1973 for his theory that honey bees communicate by a dance language. This theory was presented first by von Frisch in the 1940s. He suggested that worker bees are able to communicate direction and distance to a food source through movements described as "round dances and waggle dances."

Birds use song to recognize and attract other members of their species, to warn of predators and to defend their territories. Some birds, such as killdeer, will leave the nest and perform an elaborate "broken wing" display to attract a predator away from its nest.

Niko Tinbergren demonstrated in his research that visual displays of stickleback fish initiate reproduction. The red belly of the male stickleback attracts a female, who adopts a head up posture. In response, the male makes a series of zigzag motions, leading the female to his nest where she deposits her eggs. Finally, the male enters the nest and fertilizes the eggs.