ANIMAL BEHAVIOR
Ch 51
Animal behavior involves the actions of
muscles and glands, which are under
the control of the nervous system, to
help an animal respond to a stimulus
Behavior is subject to natural selection
The following questions are considered
when analyzing animal behavior:
• What is the stimulus that elicits the
behavior and what is the
physiological mechanism of the
response? (proximate cause)
• How do animal’s experiences
influence the response? (proximate
cause)
• How does the behavior aid survival
and reproduction? (ultimate cause)
• What is the evolutionary history of
the behavior? (ultimate cause)
• Proximate cause: what mechanisms enable
the animal to exhibit the behavior
• Ultimate cause: how did the behavior come
to be?
Behavior can be innate: developmentally fixed
behavior and nearly all members of
population exhibit the same behavior
Behavior can be learned: behavior is modified
thru experiences
I. KINDS OF ANIMAL BEHAVIOR
A. Fixed action patterns
• A sequence of unlearned acts that is
unchangeable and is usually carried out
to completion
• Example: male stickleback fish (they
have red bellies) will attack other
males that invade their nesting
territories but won’t attack females
(no red bellies)
What is the stimulus?
How could they prove this?
B. Oriented movement
• Kinesis: undirected movement
of an animal in response to
environmental condition
Pillbugs are more active in dry
conditions than in moist conditions.
Why?
• Taxis: directed movement towards
or away from a stimulus. Ex: trout
orient themselves upstream. Why?
• Migration: seasonal movement of
animals for long distance
o Is circannual
o follow sun’s position in sky,
Earth’s magnetic field or North
star
o What might be the
stimulus to initiate
migration?
o Depending on species of bird, it can be innate
or learned
o How would they determine if it is innate or
learned?
C. Behavioral rhythms
• Behavior that follows a biological
clock
o Circadian rhythms follow a daily
clock like nocturnal vs diurnal
animals
o What is the cue?
o Circannual rhythms follow a
yearly clock like mating and
migration
o What is the most common cue?
Explain the biological rhythm of the fiddler crab
D. Animal communication:
• transmission of a signal from
one animal induces a behavior
in another.
• Most animal communication is
innate
• Chemical communication: signal secreted
by one animal
o Can involve pheromones that are
secreted by females to indicate readiness
to mate
Other types of
chemical
communication?
• Visual communication
o To show courtship or aggression:
baring teeth and courtship dances
• Auditory
• Tactile = touch
o Greeting, grooming.
E. Habituation
• animal learns to ignore meaningless
stimulus
• allows animal’s nervous system to focus
on stimuli that signal food, a mate, or real
danger
• What effect does habituation have on
fitness?
F. Imprinting
• A learned behavior that is acquired
ONLY if appropriate stimulus is
provided during the CRITICAL
PERIOD
• Once behavior is acquired it is
irreversible
• In birds, young imprint on parent
and learn basic behaviors of their
species.
• If critical period passes without
imprinting, then species-specific
behavior is not learned
G. Associative Learning
• Learned behavior where one
environmental feature is associated
with another
o Classical conditioning = arbitrary
stimulus is associated with a reward
or punishment
• social learning = animal learns by
observing other animals
• Insight = animal performs a
behavior without being learned
o Operant conditioning = animal
learns behavior thru positive or
negative stimulus
II. Genetics of Behavior
A. Is behavior the result of genetics or is it
learned?
• Genes provide the instructions for
behavior
• Nongenetic factors can modify how
instructions are carried out
• Some behavior is more genetic than
learned and visa versa.
B. The purpose of behavior is to enhance
survival
What is natural selection?
Genes for behavior have evolved by natural
selection in order to enhance survival
1. Foraging behavior
• Foraging: food-obtaining behavior
• Benefit of foraging: nutrition
• Cost of foraging: energy expenditure,
risk of predation
• Therefore any foraging behavior that
minimizes costs while maximizing
benefits would be favorable
2. Mating behavior
• Mating behavior involves, attracting,
choosing, and competing for mates and
the care of offspring
• Any behavior that maximizes this is
favored
Intrasexual selection:
competition between
members of the same
sex for a mate
Intersexual
selection: where one
sex chooses mate
based on certain
traits