Chapter 1
Behavioral endocrinology: study of interaction between hormones & behaviour
o Bi-directional (hormones affect behaviour, behaviour affects hormones)
Historical Roots of Behavioural Endocrinology
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Recognized as a discipline in middle of 20 century (Hormones & Behaviour, 1948)
Endocrine Glands, Hormones, and Behaviour
Testes testosterone sexual behavior, territoriality, hibernation, migration
o Outside body, in cavity
Castration manipulation of endocrine system
o Better to eat/easier to control
Eunuchs: castrated males watched over females
o Before puberty: no effect on behaviour/appearance
o After puberty: short, long arms, no sexual behavior, secondary sex characteristics
affected (no beards, voice does not develop)
Castrati: males castrated so they can perform in Opera
Berthold’s Experiment (first formal study of endocrinology)
Results: substance produced by testes travel through blood and affects behavior
o Product of testes necessary for cockerel (immature male chicken) to develop into
normal adult rooster
Rooster mate with hens, fight, crow, large, distinct plumage
Capons (castrated male chicken; before adulthood – tender meat)
o Not the same behavioural/physical characteristics as roosters
o No mating, not aggressive, back down, don’t crow
Experiment: 6 cockerels, 3 groups (2 in each group)
First group: castrated
Developed as Capons
o Didn’t fight, crow; monotone voice, avoided females, no mating, looked different
(small head & body, pale combs + wattles)
Second group: castrated, testes placed in abdomen
Developed normal rooster behavior (crowed, same appearance)
testes attached to intestines & had vascular supply, doubled in size, sperm
Third Group: castrated, testes put in each other’s abdomen
Developed normally Three Major Conclusions Drawn
(1) Testes are transplantable organs
(2) Transplantable testes can function & produce own sperm (tree branch with own fruit)
(3) No specific nerves directing function (all nerves cut)
“secretory blood-borne product” (aka. hormone) for transplanted testes = normal development
Ideas for/from Experiment
¾ parameters for hypotheses = behavioural
o Mating, aggression, vocalization, appearance
Pangenesis theory of inheritance
o All body parts discha
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