Transcript Animal Behavior

Animal Behavior
Chapter 36
I.
Science of Animal Behavior
A. Ethology
• Ethology—study of animal behavior in its natural
habitat
• Behavior is the way an animal acts in response to
a stimulation; usually involve finding food,
interacting in social groups, avoiding predators,
and reproducing
• Idea that behaviors can be isolated and measured
to trace their evolution
• Proximate causation—physiological reasons for
animal behavior
• Ultimate causation-selective adaptations are the
reasons for certain animal behaviors
• Interested in tracing behavior across species
B. Sociobiology
• Study of social behavior
• E.O. Wilson father of sociobiology
• Reciprocal communication between individuals in a
group of the same species that is cooperative and
permits the group to become organized
• Differing levels of complexity
• individuals that act as 1 large individual,like
Portuguese man-o-war
• Social insects like bees, ants, termites
• Groups like elephants, dolphins, primates
• humans
C. Behavioral Ecology
• Individual behavior that maximizes reproductive
success
• Mate choice, foraging, parenting are all studied
II. Principles of Ethology
A. Stereotypical Behavior
• Konrad Lorenz & Niko Tinbergen were pioneers
• Automatic programmed responses to a stimulus in
the environment that may mimic intelligent
behavior (usually most effective in the wild); these
are instincts
• Releaser—any stimulus that triggers a certain
behavior
• Sign stimulus—one specific part of the stimulus
that the animal responds to
• Examples—parent’s call releasing the freeze
response in a chick; male stickleback becoming
aggressive in presence of other male’s red
coloration
B. Control of Behavior
1. Innate
• Predictable stereotyped behaviors that are
inherited
• Independent of learning but does depend on
interactions during development
• Important for survival, especially in animals that do
not have parental care
• Reflexes are simplest type and usually protective;
instinctive behavior is more complex series of
actions
• Longer lived animals may also develop additional
social and learned behaviors since have time to
acquire them
2. Genetics
• Inheritance of innate behavior depends on many
interacting genes
• Some, however, like honeybee hygiene, are just 1
gene; bees that were recessive for 1 gene,
uncapped cells that contained decaying larvae;
those that were recessive for another gene carried
out the decayed larvae
• Sometimes crossing purebred dominants and
recessives for certain traits creates hybrids that
have confused behavior
3. Learned
• Learning is modification of behavior through
experience
• Habituation—animal learns to ignore a stimulus
(perceived as harmless or unrewarding) and does not
react to it; repeated stimulation diminishes the release
of neurotransmitters from sensory neurons to motor
neurons resulting in no reaction
• Conditioning—animal connects a certain stimulus with
a certain behavior; used in training animals usually
with a reward
• Sensitization—a noxious stimulus is added to an initial
stimulus resulting in a response; later only initial
stimulus need be given to have same result
• More complex learning involves the formation of new
neural pathways and connections as well as changes in
existing circuits
3. Learning Con’t
• An animal can only learn to do what it is physically
capable of doing
• Imprinting—young animal exposed to object during
critical window of development; bond then lasts for life;
”mother”; learning bird songs
• Trial-and-error learning or operant learning—animal
relates its past experience to new stimulus
• Communication—the sharing of information that
results in a behavior change
• Language—using symbols to represent ideas
III. Social Behavior
A. Examples
• Response of one animal of a species to another of
the same species
• Males fighting over female; breeding may
sometimes be the only social interaction
• Monogamy—relationship for life
• Mother mammals and birds usually form bond with
young until weaned or fledged
• Social aggregations for feeding, warmth, protection
B. Advantages
• Passive and active defense since safer in group
than alone
• More animals in a group, less likely will be eaten
• Brings together males and females for breeding;
contact may also bring about necessary endocrinal
changes needed for breeding
• Survival of young increases
• Hunting, protection from weather, division of labor,
potential for learning and transmitting useful
information
C. Disadvantages
• If depend on camouflage for protection, better off
dispersed
• Large predators need great quantities of food
• Habitat may not support large numbers of
individuals in a certain area
D. Aggression & Dominance
• Social species must cooperate, but not at expense of
own interests such a food, mates, shelter
• Aggression—offensive physical action or threat to
force others to abandon something
• Agonistic behavior—any activity related to fighting
• Most dangerous weapons used only on prey not on
own species, relying on ritualized displays to avoid
injury or death
• Ritualized display—behavior that has been modified
through evolution to make it effective in
communication; may be used to gain access to food,
mates, or territory; loser runs away or signals defeat by
subordination ritual
• Dominance hierarchy—establishes a “pecking” order;
weaker members typically die in times of scarce
resources
E. Territoriality
• Territory—fixed area from which intruders of same
species are excluded
• May be an alternate behavior to dominance
• Ensures food supply
• Provides protected area for mating and rearing
young
• Sometimes costs of maintaining a territory
outweighs benefits
• Birds tend to form territories; mammals typically
have home ranges
F. Mating Systems
• Monogamy--1 male and 1 female mating at a time
• Polygamy—general term for any system that has
multiple partners
• Polygyny—1 male mates with more than 1 female;
male may hold critical resources to attract several
mates (resource defense); females may aggregate
making them easily defensible (female defense);
female may pick male from group of males based
on display (male dominance)
• Polyandry—1 female mates with more than 1 male
G. Altruistic Behavior & Kin Selection
• Inclusive fitness—relative number of individual’s
alleles that are passed on to future offspring or that
of related individuals
• Some insect workers, that are haplodiploid, give up
reproduction and aid the queen in reproducing;
they are 75% related to sister-queen’s offspring,
rather than only 50% if mated and had own
offspring
• In these systems, it is important to be able to
distinguish kin from non-kin
IV. Animal Communication
A. Chemical Signals
• One animal influences the behavior of another
though sounds, scents, touch, and movement
• A signal conveys one message and can not be
rearranged to construct new kinds of information
(in contrast to language)
• Chemical signals evolve easily since there is
selection for better detectors
• Pheromones are chemical signals used to attract
mates
• Female moths emit pheromones; males use
antennae that detect it and then locate female
B. Displays
1. Bees
• Communicate location of food through the Waggle
Dance
• Figure eight pattern done in comb of hive
• Waggle in middle part of the 8 indicates direction of
food source relative to the sun
• The speed of the waggle is inversely proportional
to the distance the food is from the hive
• If food is close to hive, a found dance is used
instead
• Dancing less common when food is plentiful; more
intense when food is scarce
2. Other Organisms
• Courtship dances of birds repeat many displayed
behaviors so that a commitment to courtship is
ensured
C. Language
• Animal cognition—mental function, perception,
thinking, and memory
• Studies try to detect extent to which animals are
self aware and levels of reasoning
• Humans have a hard time determining this in other
animals
• Chimps have learned 132 words in ASL
• Parrots can vocalize like humans which aids in
measuring cognition; can identify shapes, colors,
and numbers