Respect to Hormones
v Animal behaviour is closely associated with stimuli as
well as hormones.
o A chemical substance which
is released from endocrine gland and travels by blood to the target point
called as hormone.
v In 1992, Nyby Et Al. manipulate testosterone in male
mouse. He studies the effect of testosterone on social and sexual behaviour of
v For this purpose, surgery, hormone
replacement, manipulationof hormonesand concentration of hormones,
these tools was used.
v Because stimuli transfer the message to the CNS to perform different
activities and CNS send the message to the target cell by nerves or
hormones.Hormones are secreted by endocrine glands and are mostly liquid in
nature,travel by blood to the finel point.Effects of these horrmonel response
we can see in the form ofspecific animal behaviour.
v E.g. Sexual attraction by release of pheromones.
v The hormones may be used to generate social behaviour,
reproductive behaviour and aggressive behaviour,etc.
v When we talk about
hormones we should keep in mind that the CNS is directly involved in the
release of any hormone and ultimate
fate of the hormone like after
its function it will be degraded or recycled.
v All types of information
about hormone is transcribed by brain or CNS, as it affects the target cells or
tissue,the resulting pattern of action will be occur and we named this pattern
of actions as Animalbehaviour.
v When we say that an animal
is foraging then I would like to clear that it is an animal behaviour,pattern of actions. Because
different hormones produce the sensation of hunger.so, it is cleared from this
discussion that animal behaviour is a combination of stimuli hormones and
effectors.Certain other factors may also be involved like environment and
nervous system.Hormones have different effects and levels in different stages
of the life of an animal.
v EXAMPLE; The level of sex hormones is higher at puberty of animal
and animal have maximum mating capability.
vThere are different behaviours
affected by hormones some of which are given below;
v 1.Hormones and
v 2.Hormones and sex
v 3.Hormones and
v 4.Hormones and
Hormones and reproductive behaviour
v This type of behaviour is
seasonal based,during breeding season the level of sex hormones will be
secreted by pineal gland will inhibit the growth of sex organs during breeding
season.The pituitary hormones like FSH, LH
hormone effects the growth of ovary in female.These hormones are also
responsible for ovulation
during menstrual cycle.
v The egg laying capability of female is due to the effect of LH hormone and after egg
laying the incubation
behaviour of female is also affected by Prolactin hormone.As a result of the effects of
these hormones the female perform all the reproductive behaviour like mating,egglaying, incubation and
fertilization.After fertilization the development of embryo is also controlled
or affected by a set of hormones.
v During pregnancy the food demand of female animal becomes higher due
to feeding of young one and in many cases female mostly rests during these days
and male provide food to his female partner.So, ultimately during breeding
season the foraging behaviour is also affected by hormones.The sex
determination is also controlled by hormones, as given below;
and sex determination
v The behaviour for mating of male and female is helped out by
hormones.During breeding season the female releases different pheromones which attract
the male to herself for mating.Anddue to increased level of testosterone hormone in
male animals they also perform different actions to attract female for
mating. E.g. male birds singing or
v Hormones produce different changes in body stature of female or male like
during menstrual cycle, the changes in uterine wall or change in male or female
v Next we see how the mother
and father have specific behaviour;
Hormones and maternal behaviour;
v Inmost vertebratesthe mother has specific behaviour to
care her young ones.The mother feeds her young one and also care his young
In case of feeding
with milk pituitary hormone is directly involved because prolactin is involved
inthe formation of mammary
glands,which produce milk.
v If the prolactin is stopped the feeding behaviour of
mother will also be stopped.In case of mice the LH and progesterone also produces the nest building behaviour for
protection of her young one.
vFrom all above discussion it is
cleared that the animal behaviour is designed by specific hormones.
of hormones and animal behaviour;
vThe hormones are commonly protein in
nture and each hormone is coded by a specific gene.Gene is a specific sequence of
nucleotides present at specific part of DNA.When the hormone is produced
the CNS i.e hypothalamus gives destiny to this hormone.
vThese animal behaviours controlled by
hormones helpan animal in its survival and increase its reproductive rate.
Ultimately the successful behaviour
controlled by hormones helps animal to gain such features that give it success
in evolution.Due to having these fruitful pattern of actions,nature selectsit.So indirectly hormones helps in