1. Animal behavior as
screening tool
Presenter: Priyanka Kumawat

2. • Behavior is what an animal does and how it does it.
What is Behavior?
• Animal behavior asks what, why, and how.
• Study of Animal behavior is also referred to as Ethology.
– Scientists who study animal behavior are called
Ethologists.

3. Niko Tinbergen(Dutch)
• Niko Tibergen(noble prize holder)
pioneer (first to do something) in
the field of ethology and
ornithology.
– Observed animals in their
natural conditions, then
manipulated the conditions
to see how the animals
responded.
Image from http://nobelprize.org/

4. • Animal behavior is
centered around the
ability to move.
– Animals seek food,
water, shelter.
– Animals play with
each other.
– Animals seek
mates.(reproducti
on)
Behavior Patterns

5. • Behavior results as a reaction to a
stimulus.
– A stimulus is a detectable change in
the animal’s internal or external
environment.
– Hunger.
– Sound.
– Pain.
– Visual cues(stimulus).
– Hormonal changes.
Image from http://www3.nau.edu/biology/

8. Nature versus Nurture:
Revisiting an Old Debate
Nature
Behaviors are:
• Innate
• Hard-wired
• Instinctual
• Genetically determined
Nurture
Behaviors are:
• Learned
• Flexible
• Not genetically
determined
Behavior results from both genes and
environmental factors

9. MAJOR TYPES OF ANIMAL BEHAVIOR
• Sexual
• Maternal
• Communicative
• Social
• Feeding
• Eliminative
• Shelter-Seeking
• Investigative
• Allelomimetic-
contagious behavior

10. TERMS TO KNOW
1. Innate behavior
Instinct – (reflexes and responses) what the animal has at birth
(innate behavior). Ex. Nursing, Foraging/ searching for food.
2. Learned behavior
Habituation – learning to respond without thinking, response to
certain stimulus is established as a result of habituation.
Conditioning – learning to respond in a particular way to a stimulus
as a result of reinforcement when the proper response is made.

11. TERMS TO KNOW
• Reinforcement – a reward for making the proper
response.
• Reasoning – the ability to respond correctly to a
stimulus the first time that a new situation is
presented.
• Intelligence – the ability to learn to adjust
successfully to certain situations. Both short-term
and long-term memory are part of intelligence.

12. • Associative learning - ability of many animals to
associate one feature of their environment with
another feature.
– Classical conditioning- when two stimuli are
regularly paired in close succession:
– Operant conditioning- Modification of behavior by
reinforcing or inhibiting effect of its own
consequences

13. Experimental models based on animal behavior
• An animal model with biological and/or clinical relevance in the behavioral
neurosciences is a living organism used to study brain–behavior relations
under controlled conditions, with the final goal to gain insight into, and to
enable predictions about, these relations in humans
B R A I N R E S E A R C H R E V I E W S 5 2 ( 2 0 0 6 ) 1 3 1 – 1 5 9
1. Pain behavior
2. Anxiety behavior
3. Depression
4. Psychotic behavior
5. Sedative/hypnosis
6. Memory/learning
7. Aggressive behavior

14. Criteria of assessing the validity of animal
models of human behavioral research
• Face validity- degree of descriptive similarity ,eg: the
behavioral dysfunction seen in an animal model and in the
human affected by a particular neurobehavioral disorder
• Internal validity - quality of the experimental evaluation of the
animal model
• Predictive validity/ criterion validity- Accuracy with which
animal model predicts the course of outcome of the human
phenomenon Behavioral and Brain Functions 2009, 5:11

15. • Construct validity- degree of similarity between the
mechanisms underlying behavior in the model and that
underlying the behavior in the condition, which is being
modeled.
• External validity/Generalizability- extent to which the results
obtained using a particular animal model can be
generalized/applied to and across populations or the extent to
which experimental findings make us better able to predict
real-world behavior” Behavioral and Brain Functions 2009, 5:11

16. Behavior of Animals used as disease models
Pain behavior

17. • Decreased activity
• Abnormal postures, hunched back, muscle flaccidity or
rigidity
• Poor grooming/ Overgrooming
• Decreased food or water consumption
• Decreased fecal or urine output
• Weight loss (generally 20-25% of baseline), failure to
grow
• Decrease or increase in body temperature
• Decrease or increase in pulse or respiratory rate
• Physical response to touch (withdrawal, lameness,
vocalizing, increase in pulse or respiration)
• Teeth grinding (bruxism) (seen in rabbits and farm
animals)
• Self-aggression
• Withdrawal from pain stimulus (tail flick)
• Squinting (especially ferrets)
Guidelines for the Prevention,
Assessment and Relief of Pain and
Distress in Laboratory
Animals.University of Minnesota Board
of Regents.2000
Grooming- licking all
reachable parts of body

18. Pain models
Acute pain models
• HAFFENER’S tail clip method (Rats)
• Tail flick (radiant heat) (Rat)
• Hot plate method
• Tail immersion test
• Electrical stimulation of tail
• Grid shock test
• Tooth pulp stimulation (rabbits)- licking,
biting, chewing, head flick
Chronic pain models
• Formalin test in rats (elevation / favoring
of paw or excessive licking / biting of
paw)
Pharmacology- Analgesics- Central
• Randall selitto test (Rats)-
struggles, squeals / attempt to
bite on squeezing the paw
injected with Brewer’s yeast
suspension
• Writhing test (rats)-stretching
behavior i.e. writhing
Pharmacology- peripheral analgesics
+ central analgesics

19. Psychotic behavior

20. Psychotic behavior of animal simulating human
psychiatric disease
• Aggressive behavior (Hamster)- (turning, vocalizing,
biting) on handling with forceps
• Stereotypic/ compulsive behavior in rats and mice-
repetitive purposeless movements eg: rearing,
continuous sniffing, licking of the wall of the
container
• Decreasing shy behavior of cotton rats (hiding itself)
by neuroleptics Methods of Behavior Analysis in
Neuroscience. NCBI Bookshelf. 2009

21. Sniff- probes its snout along and around
surfaces
Rearing-
Standing on
rear limbs
Licking the
wall of the
cage

22. Screening models for schizophrenia
Behavioral tests
• Catalepsy in rodents
• Pole climbing avoidance in rats
• Golden hamster test-Agression when
held by forceps
• Influence on behaviour of cotton rat
• Foot shock induced aggression
• Apomorphine induced compulsive
behavior
Pharmacology- Antipsychotics
(chlorpromazine)
Tests based on the mechanism of
action
• Amphetamine-induced
hyperlocomotion
• PCP-induced hyperlocomotion
• Amphetamine-induced disruption
PPI
• PCP-induced disruption PPI
• Conditioned Avoidance
Responding
• Inhibition of apomorphine
climbing in mice
• Yawning and penile erection
syndrome in rats
• Inhibition of mouse jumping

23. Anxiety behavior

24. • Anxiety is a biologically relevant adaptive behavioral response and
therefore not negative by nature. Subjective sense of unease,
dread, or foreboding
• Generalized anxiety disorder (unrealistic worry about everyday life
situations) and panic disorder (sudden, extreme fear accompanied
by autonomic nervous system arousal)
• Basic physiological mechanisms underlying fear in rodents can be
equated to similar mechanisms operating in humans provides a
degree of face validity for these paradigms
Methods of Behavior Analysis in
Neuroscience. NCBI Bookshelf. 2009

25. • Rats and mice tend to avoid open spaces, brightly illuminated
light.
• In open spaces :avoidance of danger :less ambulation or
immobilization , less grooming, less rearing .
• Drugs having anxiolytic activity increases exploratory behavior
of some animals
• Anxiolytic behaviour of the drug is indicated by-
• Increased ambulation
• Decreased immobilization
• Increased rearing
• Increased grooming

26. Anxiety models

27. EFFECTS ON BEHAVIOR
Light-dark model Foot shock induced freezing behaviour in
rats
Anticipatory anxiety in mice Experimental anxiety in mice
Social interaction in rats Distress vocalization in rat pups
Elevated plus maze test Acoustic startle response in rats
Water maze test Unconditioned conflict procedure(Vogel
test)
Staircase test Novelty-suppressed feeding
Cork gnawing test in the rat Shock probe conflict procedure
Hole board test Ultrasound induced defensive behaviour in
rats
Schedule induced polydipsia in rats Anxiety / defence test battery in rats
Four plate test in mice Marmoset human threat test

28. Depressive behavior

29. Methods of Behavior Analysis in Neuroscience.
NCBI Bookshelf. 2009

30. Human symptom Behavioral sign Preclinical tests

31. Models of depression
1. Despair swim test.
2. Tail suspension test in mice.
3. Learned helplessness in rat.
4. Muricide behavior in rat.
5. Behavioural changes after neonatal clomipramine treatment
6. Maternal separation experiments in infant nonhuman primates
7. Chronic mild stress model- mild stressors such as disrupted light-
dark cycle, wet bedding, having an intruder rat placed in the home
cage, or having the home cage tilted at an angle for 1 to 2 days

32. Sedative/ hypnosis
• In man Sedative and hypnotics is to obtain a “ normal”
night’s sleep from which the patient can be aroused
without any subsequent hangover.
• In animals
“hypnotic” applied to a much deeper stage of central
depression of drug induced unconsciousness.
Associated with loss of muscle tone and of righting
reflexes.

33. Models
1) Potentiation of hexobarbital sleeping time
2) Experimental insomnia in rats
3) EEG registration in conscious cats
4) Automated rat sleep analysis system
5) Phenobarbital induced loss of righting reflex

34. Memory and learning
behavior

35. Alzheimer's disease models
• Most prominent striking sign is progressive decline in
cognition
• Behavioral /cognitive tasks
• Associative learning- cues in the environment to condition a
specific response in animals (Spatial cues), adaptive process
that allows an organism to learn to anticipate events.
• Operant learning- Stimulus is given to make animal
responsive so as to obtain a outcome
• Basis- SUBJECT → DOSE OF DRUG → RESPONSE →
REINFORCEMENT

36. Task Models
Spatial Memory Tasks The Morris Water Maze
Radial Arm Maze
Radial Arm Water Maze
Contextual Memory Fear Conditioning
Passive-Avoidance Learning
Working Memory/Novelty/Activity Y-Maze
T-Maze
Object Recognition
Open Field
Working Memory Delayed Response
Tasks in Monkeys
TRANSGENIC MOUSE MODELS OF
ALZHEIMER’S DISEASE
Amyloid-β Transgenic Mouse Models
Tau Transgenic Mouse Models

37. Offensive /Aggressive
Behaviors

38. Models of aggression
• Behavior which is ‘‘violent,’’ ‘‘hostile,’’
‘‘agitated,‘‘impulsive,’’ or ‘‘pathologic aggressive.’’ in
humans
• Any overt behavior that produces aversive stimuli or
harm to another organism.
• Related animal behavior- Attack behavior, Chatter
(teeth-chatter)- grinding of the incisors against each
other(Rats)

39. Models
• Isolation-induced offensive behavior (mouse)
• Resident-intruder offensive behavior (rat/mouse/hamster),
• Offensive behavior after electrical stimulation of the brain
(rat),
• Maternal offensive behavior (mouse/rat),
• Offensive play fighting among juvenile rat
Relevant pharmacology-
• Benzodiazepines, neuroleptics, psychostimulants,
antidepressants, serenics

40. Available Preclinical Models
Anxiety
• Light/Dark Box
• Stress-Induced
Hyperthermia
• Elevated Plus Maze
• Fear Potentiated Startle
• Vogel Test
• Punished Responding
• Conditioned Fear
• Open –field test (OFT)
Pain Assays
• Hot Plate
• Tail Flick
Depression
• Forced Swim
• Tail Suspension
• maternal separation experiments in
infant nonhuman primates
• learned helplessness model.(Acute
stress)
• chronic mild stress model-
Parkinson’s Disease
• Reserpine-Induced Akinesia
• Haloperidol-Induced Catalepsy
• Unilateral 6-OHDA Forelimb
Asymmetry

41. Cognition
• Rat Mouse Location
• Five Choice Serial Reaction Time
• Conditioned/Cue Freezing Test
• T-maze
• Water Maze/Barnes Maze/Radial
Arm Mouse Core
Other Behavior
• Drug Discrimination
• Self-Administration
• Attention behavior
• Drug abuse
Schizophrenia
• Amphetamine-induced
hyperlocomotion
• PCP-induced
hyperlocomotion
• Amphetamine-induced
disruption PPI
• Conditioned Avoidance
Responding
Motor
• Rotorod
• Inverted Screen
• Locomotor Activity
• Body Temperature
• Irwin Neurological Battery

42. References
• Experimental animal models for the simulation of depression
and anxiety. Eberhard Fuchs, PhD and Gabriele Flügge, PhD.
Dialogues in Clinical Neuroscience - Vol 8 . No. 3 . 2006
• Animal models of behavioral dysfunctions: Basic concepts and
classifications, and an evaluation strategy. F. Josef van der
Staay. B R A I N R E S E A R C H R E V I E W S 5 2 ( 2 0 0 6 ) 1 3
1 – 1 5 9
• Chapter 118: Animal Models of Aggression
Neuropsychopharmacology: 1700 The Fifth Generation of
Progress

44. Classical Conditioning

45. 2. operant conditioning
a. perform behavior to receive reward or avoid punishment
b. Skinner Box - levers, reward - self training elaborate protocols
c. behavior first, reward second
(but of course there is a stimulus, if only a thought of reward)

46. • Skinner's Operant Conditioning
• B.F Skinner's theories of operant conditioning
describe how behaviour can be modified through
reinforcement and punishment. A common example
is that of a rat in an isolated "Skinner Box", that is
rewarded with food when it presses a lever. In
pressing the lever, the rat experiences a positive
outcome. This 'modified' behaviour becomes
ingrained to the rat; that is, it learns how to behave
in a manner that produces desired results.

47. Learned Behaviors:
• Operant conditioning occurs as an animals learns to
associate one of its behaviors with a reward or
punishment.
– Rewards: increase the behavior
– Punishments: decrease the behavior
– Skinner
– Trial-and-error learning

49. Commonly used lab. animals
• Kingdom: Animalia
• Phylum: Chordata
• Class: Mammalia
• Most widely used:
• Mammals: Monkey, baboons, chimpanzees, cat,
dog, ferrets, shrew , gerbil, guinea pig, rat,
mouse, oppossum, mice
• Other less widely used:
• Birds, reptiles, amphibians, fish, shark
Almost all lab.
Animals belong to
mammalia class

50. Animals
– Rodents:
– Rat (Rattus norvegicus)
– Mouse (Mus musculus)
– Guinea pig (Cavia porcylus)
– Gerbil ()
– Hamster ()
– Didelphimorphs
• Opossum ()
– Insectivores
– Least shrew (Cryptotis parva)
– Asian musk shrew (Suncus murinus) (vomits-CTZ
ab.-Other brain area involved )

51. Innate Behaviors – inherited, instinctive
A. programmed by genes;
B. highly stereotyped (similar each time in
many individuals)
C. Four Categories
1. Kinesis
2. Taxis
3. Reflex
4. Fixed Action Pattern

52. 1. Kinesis: "change the speed of random movement in response
to environmental stimulus“
2. Taxis: "a directed movement toward or away from a stimulus;
positive and negative taxes
3. Reflex: "movement of a body part in response to stimulus".
4. Fixed Action Pattern (FAP): "stereotyped and often complex
series of movements, responses to a specific stimulus",
hardwired, however, not purely genetic, may improve with
experience
a. programmed response to a stimulus
b. stimulus of FAP = "releaser", sometimes called "sign
stimulus“
c. examples:
- courtship behavior
- rhythms - daily (circadian); annual (circannual)

53. How to determine WHY – action patterns.
• Action patterns are complex behaviors that are always
repeated the same way by a species of animal.
– We say that action patterns are stereotyped, since
they occur the same way each time, and through to
completion.
– After repeatedly observing action patterns, an
ethologist can analyze the data statistically.
– (Statistics is the study of the collection, organization, analysis,
interpretation and presentation of data)
– Only then do we attempt to determine WHY a
behavior is being done.
– Fixed Action Patterns (FAP) are INNATE

54. COMMON RABBIT POSTURES, BEHAVIORS, AND
VOCALIZATIONSa
• Purring or teeth purring—A sound made by lightly and quickly
grinding/vibrating the teeth as the whiskers quiver; a sign of
contentment.
• Oinking or honking—A sound made to gain food or attention or during
courtship.
• Clicking—A happy sound often made after a welcomed treat is given.
• Wheezing or sniffing—Nasal sounds made by ‘talkative’ rabbits; can be
distinguished from abnormal respiratory sounds because they
• are intermittent and stimulated by interaction with the rabbit.
• Whimpering or low squealing—A fretting noise that is made when one
picks up a rabbit that is reluctant to be handled; made more
• often by pregnant and pseudopregnant does.
• Chinning—Rubbing the secretions from the scent glands under the chin
on inanimate objects and people to mark possession. Glands
• are more developed in males than females.
Use of behavior analysis to recognize pain
in small mammals Volume 36, No. 6 | JUNE 2007

55. COMMON RABBIT POSTURES, BEHAVIORS, AND
VOCALIZATIONS continue…
• Nudging or nuzzling—The nose is used to nudge a person’s hand or foot, or the
rabbit may pull on a pant leg to signal a desire for
• attention. When enough petting has been done the rabbit may push the hand
away.
• Head shaking, ear shaking, body shudder—A shake of the head or body in
response to an annoying smell or unwanted handling;
• often occurs as a rabbit settles down and becomes relaxed enough to begin
eating and grooming.
• Courting or circling—A sexual or social behavior whereby a rabbit circles another
rabbit or the feet of a human while softly honking.
• Scratching at the floor—A rabbit may scratch at the floor with its forepaws in
order to get a person’s attention or to be picked up.
• Nipping—Not always done in anger, this can mean ‘move over’ or ‘put me down’.
• Presentation—The head is extended forward with the feet tucked under the body
and the chin placed on the floor in order for the
• rabbit to present itself as subordinate for petting from humans or to be groomed
by another rabbit.

56. • Flattening—A fear response wherein the rabbit flattens its abdomen onto the floor with ears laid
back against the head; the eyes may
• be bulging.
• Thumping—A sharp drumming of the hind feet as a warning or an alert to other rabbits of danger;
often accompanied by dilation of
• the pupils and seeking of refuge.
• Teeth grinding—A slower, louder teeth crunching, sometimes seen with bulging of the eyes and
usually indicating discomfort, pain,
• or illness.
• Snorting or growling—A warning sound, either hissing or a short barking growl, that occurs with
aggression or fear and is often seen
• with the ears flattened against the head and the tail up and in the grunt-lunge-bite sequence.
• Isolation—When a rabbit that normally seeks attention from its mates and human companions
isolates itself and is less active. Such a
• rabbit should be checked for illness.
• Kicking—If a rabbit feels insecure when being picked up it will kick violently in an effort to escape.
The hindquarters must be supported to
• prevent trauma to the spine or legs. A rabbit should be placed hind-end first into a cage in order
to help prevent injuries caused by kicking.
• Aggression—Strained, upright stance with tail stretched out and ears laid back in defensive
posture; the rabbit may also kick high and
• backwards.
• Loud, piercing scream—Similar to a human baby crying; signaling pain and fear, as when the
rabbit is caught by a predator.
• Scanning—A rabbit with impaired vision may move its head from side to side to scan the area
around it.

58. Rat behavior glossary
• Self-barbering is also found in non-lactating rats, in which case the rat may nibble off fur from its forearms and
chest. Barbering is sometimes caused by Demodex mites, or as a result of mutual grooming when the rats' diet
contains more than 20% fat. Other possible causes include skin ulcers (pyoderma), other external parasites,
genetic disorders, caloric or protein deficiencies, abrasion on rough surfaces, hormonal imbalances, chronic renal
disease, ringworm (dermatophytosis), and intensive breeding (Harkness and Wagner 1995).
• Behavioral Estrus (female behavior in heat): Phase of the female rat's ovarian cycle during which she displays
reproductive behavior. Behavioral estrus corresponds to vaginal proesturs, the 12 hour period before ovulation.
• During behavioral estrus, the female solicits the male to prompt him into mounting her. She darts towards him
and runs or hops away. She may repeat this approach-retreat sequence several times, sometimes wiggling her
ears. She may also pause near him or run by him, and may intercept him in his pursuit of another female. The male
finds these solicitation behaviors very attractive, and follows the female. If he mounts her, the pressure he exerts
on her flanks, lower back, and anogenital area triggers lordosis, the female mating posture (Nelson 1995).
• Belly-groom or "power grooming": One rat grooms a recumbent rat's belly. May be an attempt to reach the nape,
which is the goal of play fighting. See also "Belly-up

59. • roll" and allogrooming.
• Belly-up roll (pin): Juvenile-type defense tactic in which one rat rolls onto his back before another,
sometimes after receiving a nip or bite on the rump. The top rat may then step on the supine rat,
sometimes orienting himself perpendicular to the long axis of the supine rat (thus avoiding the
whiskers), and pinning him down. The top rat may groom the supine rat's belly (see also belly-
groom, or "power groom"), perhaps as an attempt to gain access to the nape or rump. Rolling on
one's back tends to prevent further attack for several reasons: play fighting is directed at the nape,
and serious offensive bites are directed at the lower back and flanks, so a roll hides these areas.
Also, the rolled rat becomes motionless, and motion is an important stimulus for attack (Thor et al.
1981). Lastly, the recumbent rat may track his opponent's face with his teeth and whiskers, which
may actively inhibit attacks as well (Blanchard and Blanchard 1977).
• So, the belly-up roll is probably not a signal of submission or defeat that inhibits further attack,
because the attaker may continue to press his attack. The belly-up roll is instead a defensive
strategy: the subordinate rat can escape being bitten insofar as he can interpose his belly between
the attacker and his own vulnerable target areas of rump and nape.

60. • Box: Two rats stand on their hind legs face to face and nearly nose to nose, and push or paw at each other with
their front legs and paws, usually around the head, neck, shoulders and front legs of their opponent. In high
intensity boxing the rats stand erect on their hind feet and rapidly push, paw, and grab at each other. In low
intensity boxing the rats squat on their haunches and paw at each other gently. If no contact is involved, the
encounter is a nose-off. Boxing is a defensive strategy: as long as the subordinate rat maintains whisker-to-whisker
contact, the dominant rat cannot bite his rump. The dominant rat may respond to the boxing tactic with a sidle
(Blanchard et al. 1977).
• Bound (ricocheting jump): Rat advances with leaps: it pushes off with both hind feet, lands on both front feet,
brings forward the hind feet and pushes off again. The rat spends 3/4 of its time in the air: in one beat, the
forefeet hit the ground followed quickly by the hind feet, which push the rat into the air, and three beats later the
forefeet hit the ground again. The back arches when the hind feet are brought forward, making bounding very
conspicuous. The rat may also thump at each bound when it hits the ground.
• Brux : Soft, repetitive grinding of the incisors against each other. Serves the sharpen the incisors and may be given
in times of relaxation or stress (Rosales et al 2002, Pohto 1979). Also see chatterr
• Caching, or Stashing: The rat picks up a food item in its mouth, runs elsewhere, and deposits the food item. The
rat frequently leaves the item there and returns for another load. The place a rat chooses to cache food in is
usually a protected, hidden or semi-hidden location, such as a nestbox, a dead-end passage, or a dark corner.

61. • Chase, or pursuit: Running behavior in which a rat pursues a target individual. If the chase occurs in
a social context, the pursuer may deliver a nip to the fleeing rat's rump if he gets close enough. Rats
may also pursue prey.
• Chatter (teeth-chatter): Repetitive grinding of the incisors against each other. May be given during
intense agonistic encounters, and may represent an internal conflict (dual activation) of attack and
flight tendencies (Lammers et al. 1988). May be louder and may contain more sharp crackling
sounds than bruxing in a relaxed context.
• Chew (mastication): Grinding and shredding of food between the molars. The lower jaw is in the
back position, such that the molars are in contact with each other and the incisors are not. Chewing
is involved in processing food prior to ingestion, and is quite different from gnawing. For details on
the exact biomechanics of chewing, see Weijs (1975); Weijs and Dantuma (1975).
• Climb: Vertical locomotion up or down a vertical surface. Rats may scale just about any vertical or
slanted surface with a sufficient handhold. They use both forefeet (pull) and hind feet (push) to
grasp footholds and haul themselves up. They may use their claws if they can't use their toes, as
when climbing a screen or fabric. Rats climb up more easily then they descend. They descend head
first, and appear to have some difficulty controlling their weight and speed on descent. A rat may
start a descent and may then jump or fall the rest of the way.

62. • Dig: Rats dig by pulling handfulls of dirt backwards with their front paws,
making a pile under their stomachs. Sometimes the rat uses its whole
forebody to pull a load backwards. Periodically they clear the accumulated
pile by kicking it backwards with their hind feet. Rats may clear tunnels by
pushing dirt with their forepaws and head.
• Dorsal Immobility, or transport immobility response: Freezing or "going
limp" behavior that occurs when rats are picked up by the scruff of the
neck. The response is triggered by constriction of the skin at the nape
(Mileikovsky and Nozdrachev 1997). Dorsal immobility is seen primarily in
juveniles when their mother picks them up and transports them from
place to place (e.g. retrieving pups back to the nest) (Wilson and Kaspar
1994). Going limp probably helps the mother carry the baby, and the
dorsal immobility response is seen in the juveniles of many different
altricial species. The response persists into adulthood in rats, as adult rats
may continue to freeze when picked up by the scruff

63. • Eye-boggle (eyeboggle, boggle): Eyeball vibrates rapidly in and out of the socket.
Occurs during high-intensity bruxing (soft, repetitive grinding of the incisors). The
rat's masseter muscle, which passes through the eye socket behind the eyeball,
moves the jaw rapidly up and down during bruxing. When bruxing is intense, the
contractions of the masseter vibrate the eye in and out of the socket in time with
the incisor grinding. Usually considered to indicate pleasure and contentment.
• Flank Mark: Flank marking is a scent marking behavior involved in olfactory
communication, in which scent from the flank (presumably from the flank
sebaceous glands, Ebling 1963) is rubbed onto objects in the environment.
Typically, the rat leans sideways into a vertical structure (like a wall or the edge of a
burrow entrance) and pushes its side against the surface while pulling itself
forward. Males flank mark more than females. Flank marking tends to be
performed in familiar environments (Peden and Timberlake 1990).
• Flight: One rat runs away from the other, the second rat may or may not pursue.

64. • Forequarter pivot: Adult defense tactic, in which the defending rat stands on its hind legs and pivots its
forequarters to face the attacker, but leaves its hindquarters in contact with the ground. The forequarter pivot
enables the rat to launch a counterattack. The more juvenile defense is the belly-up roll, in which the hindquarters
follow the forequarters and the rat ends up on its back.
• Gallop: limbs of both sides move nearly in synchrony (e.g. left and right front legs move nearly together, left and
right hind legs move nearly together). The gallop is a fast, asymmetric gait, with a period of free-flight (all four
limbs off the ground).
• In an extreme form the gallop may become a bound or ricocheting jump, in which the forefeet hit the ground, then
the hindfeet hit the ground, then three beats later the forefeet hit the ground again (Gambaryan 1974, mentioned
in Golubitsky et al. 1999)
• Gnaw: The rat pulls its lower jaw forward with its jaw muscles, such that its incisors touch each other and its
molars do not. The upper incisors hold the object, and the lower incisors are pulled powerfully upward to cut
against it. Gnawing is a rodent's speciality, and their specialized jaw muscles and jaw atriculation give the rodent a
very effective, powerful gnawing action. Gnawing is quite different from chewing, which is used to process food
prior to ingestion.

65. • Head Bob (sway): Movement of the head up and down or side to side. May
precede a jump over a gap. Rats bob their heads in order to gain a sense of visual
depth (distance between themselves and a far away object) using motion parallax
cues. Albinos may sway more frequently than pigmented rats because albino vision
is very poor. For more on depth perception and the vision of pigmented and albino
rats, see What do rats see?
• Hide: One rat retreats to a safe area, preferably far away from the aggressive rat.
He may stay there, sitting quietly for a long time, sometimes up to an hour.
• Hiss: Vocalization made during escalated agonistic encounters, typically when rats
are very close to or in contact with each other. Such escalated conflicts tend to
occur when the rats are confined and cannot escape each other, as escape takes
precedence over fighting and hissing. Hisses tend to last about 1 second and have
no discrete begining or end, which makes identification of the hissing rat difficult.
Hisses also have an ultrasonic component Berg and Baenninger 1973). The two
hisses I have heard were emitted by the defensive rat. To read more about rat
vocalizations, go to the

66. • Kick: May occur when a sidling rat approaches
another very closely. The hind foot closest to the
second rat kicks out, and may contact the second rat
on the flank or higher on the the back.
• Offensive kick: The rat's offensive kick looks more like
a hind-foot grab which pulls the two rats into a close
encounter, perhaps enabling the kicker to position
himself just prior to a fight.

67. • Nibble: Rats may nibble their own skin or that of other rats with their teeth. Under
normal circumstances they do not bite off the fur, but rather appear to be combing
the fur with their teeth and nibbling the skin underneath. If nibbling is excessive it
may become self-barbering or barbering of another rat.
• Nip: Light pinching contact with the teeth, skin unbroken. May elicit a squeak.
• Nose-off: Two rats stand immobile, facing each other. The rats may have all four
paws on the ground, or may have one or both front paws up (in which case a nose-
off may segue into boxing). Sometimes one rat leans in toward the other while the
second rat leans away from him (the rat who leans in is usually the dominant rat).
Generally, the closer the rats are to each other, the more intense the encounter.
The nose-off may be accompanied with the open-mouth tooth display from the
subordinate rat. Nose-offs are a defensive strategy: as long as the subordinate rat
maintains whisker-to-whisker contact, the dominant rat cannot bite him. Nose-offs
may escalate into boxing. The dominant rat may respond to the nose-off or boxing
tactics with a sidle (

68. • Scratch: Rats may raise a hind foot and scratch themselves, usually with rapid movements of the
hind foot and claws. They can reach their head (eyes, ears etc.), neck, front leg and side with their
hind foot.
• Widget scratching his flank with a hind foot
• Snip scratching his forehead with a hind foot
• Shriek: Loud scream that covers many frequencies at once, from 0.2 to 20 kHz and perhaps up into
ultrasound. Heard during fights, or when rat is in pain, or in strong protest. To read more about
shrieks and to hear shriek samples, go to the Norway Rat Vocalizations Page.
• Sidle (lateral display, crab walk, crowd): Threatening posture in which one rat (usually but not
always the dominant one) approaches another rat sideways or broadside ("crab walks"), with his
back strongly arched, and crowds the second rat. Sidling may a successful strategy to counter boxing
and acheive a rump bite. If physical contact is made, the sidle may become a push. The sidling rat
may also kick.

69. • Sniff: cluster of movement sequences in which (1) the rat probes its snout along and around surfaces in a
series of discrete head movements, (2) the tip of the snout and the whiskers are in brisk motion, (3) the rat
breathes in and out rapidly (Welker 1964). Sniffing is often a component of exploratory behavior. Through
sniffing, the rats sample their surroundings by smell and whisker-touch.
• Solicitation: Female initiation of sexual interaction. A female rat in behavioral estrus will attempt to initiate
and maintain mounting behavior by soliciting the male. She darts towards him, then runs or hops a short
distance away. She may wait a bit, move back, wiggle her ears, and repeat the sequence. This is calledfull
solicitation. In partial solicitation she pauses in front of the male (touchback) or runs past him (runby). In
an interception, she darts in front of a male who is following another female and distracts him.
• The male rat finds these behaviors very attractive, and he may be motivated to follow and mount the
female. The touch on her back triggers lordosis in her, the female arched-back mating posture that enables
copulation. For more, see Nelson 1995.
• Squeak, long: Loud, high pitched 0.2-0.3 sec note that stays relatively constant in pitch. Given by
subordinate rat during belly-grooming, during other tense encounters, or in strong protest. A variation is
the broken long squeak, which is a long squeak that is broken into two notes. To read more about long
squeaks and to hear squeak samples, go to the Norway Rat Vocalizations Page.

70. • Squeak, short: High pitched, 0.2 sec note that sweeps slightly upwards in pitch. Heard during head grooming and
mild social interactions. Variations include the chirrup (broken, double-note short squeak), and the squeak-churr
(sqeak that ends in a broad-band vocalization that sounds like a soft "churr"). To read more about short squeaks
and their variants, and to hear squeak samples, go to the Norway Rat Vocalizations Page.
• Tail carry: rats may pick up their tails in their mouths and carry them. May be a form of displaced maternal
behavior by mother rats. Pregnant rats who are deprived of all nesting material still attempt to build nests by
carrying their tails again and again to the chosen nest site. Mother rats with nursing litters may retrieve their own
tails to the nest.
• Tail writhe (tail wag, tail swish): Tail moves sinuously on the ground, and may bang on the floor. The movement
may involve the entire tail, or as little as the tail tip. Tail writhing is frequently seen during nose-offs. I have also
been able to elicit tail writhing by covering the rat's head with my cupped hand and pressing down gently.
• The function of tail writhing is unknown. Tail writhing may indicate a high degree of tension or excitement,
possibly negative excitement. For example, lactating females may swish their tails during aggressive encounters
with each other (Adams and Boice 1983).

72. Depressive behavior
• Learning to be Helpless
• In 1965, Seligman conducted an experiment of which the results seemed to contradict what Skinner's theories might expect. The experiment, similar
to Skinner's, involved placing a dog in a 'shuttlebox' that was divided into two compartments, these being separated by a low fence. Initially, dogs
were administered an electric shock in combination with an auditory stimulus. The idea was that the dogs would associate the stimulis with the
electric shock that followed it, and somehow change their behaviour upon exposure to the stimulus, in order to avoid the shock.
• Seligman was surprised that some dogs did nothing to try and escape the shock, even though they were in a situation where they could easily avoid it
- they simply needed to jump over the fence to the other compartment. In previous experiments, Seligman had administered an electric shock to
some of the dogs while they were restrained in harnesses. A surprising observation was that these dogs didn't even try to escape the shock - they
simply lay there and waited to be shocked! The dogs had learned to be helpless! Previously restrained in their harnesses, they had learnt that since
they had no control over their environment, nothing they could do mattered, so there was no point trying to escape the shock.
• So what?
• Learned helplessness has a correlation to theories of optimism, motivation, explanatory styles, and learning in general. As in Seligman's experiments,
if children form the opinion that they have no control over their environment and that nothing they do matters, their learning may be adversely
affected. The effects of learned helplessness are varied and significant and may include:
• lack of self-confidence
• poor ability to problem-solve
• lack of attention
• lack of self-worth
• lack of motivation
• tendency toward pessimism
• may fall toward depression
• tendency toward anti-social behaviours (unable to gain recognition through academic performance, they may seek recognition by other means - eg.
bullying)
• Shields (1997) considers learned helplessness a motivational problem. Children affected by learned helplessness generally lack instrinsic motivation;
they, like the dogs, see no point in trying, since they have the opinion that their actions will never bring about positive outcomes. Instead, such
children seek extrinsic motivational factors such as recognition as a 'bully', as described above.

73. RAT
Normal
behavior
Drug modifying
it
Model for
experiment
Muricide 10 to 30% of
rats kill the
mouse by biting
the animal
through the
cervical cord
within 5 min
selective
inhibition by
antidepressats
Antidepressant
s screening

74. Caution….
• Models detect antidepressant-like activity quite quickly, within
minutes or hours, and the drugs are given prior to the testing,
thus producing a behavioral alteration rather than preventing
a disease-induced type of behavior.
• Basal state of lab animals undergoing closely mirrors what is
known about the neural changes that occur in depressed
humans.
• As outlined above, the ideal model should respond to chronic,
but not acute, treatment with conventional antidepressants.
• Effect of psychotropic drugs on natural action patterns of
behavior should be performed during the dark phase of the
light-dark cycle(means that animals must be housed under a
reversed light-dark schedule)