4. HORMONES AND BEHAVIOR
215
incubation) seem to be quite definite and amenable to such treatment.
What appears to be an early stage in the evolution of parental behavior
is described by Dharmakumarsinhji (188) in his note on the copulatory
behavior of the marsh crocodile. The interest of Noble and Mason (185)
did not extend beyond the care of the eggs by the blue-tailed skink,
Eumeces fascicvtus, but they noted that one female in their series remained on the nest with the young for over 2 days after they were
hatched.
Many of the structural changes which follow gonadectomy and hormonal treatment are described by Dodd (123), by Forbes (135), and
by Kehl and Combescot (189) in their reviews. The assumption is justified that the relationship between the gonadal hormones and behavior
is also close. Direct evidence is provided by the increased aggressiveness
of turtles and lizards given testosterone propionate (190-194)
and by
the courtship and mating behavior displayed by gonadectomized male
and female Anolis carolinensis following treatment with estradiol dipropionate and testosterone propionate (186, 193, 194). Presumptive evidence for the relationship between the testes and the behavior of the
male is given by the correlation between the postspermatogenic steatogenesis and the autumnal sexuality of some vipers (195). Evans (178,
196) reported that ovarian hormone inhibits aggressiveness in female
Anolis carolinensis. Intact individuals are not aggressive toward other
females in the cage, but following ovariectomy they dominate females
and smaller males. Greenberg and Noble (182), on the other hand,
found no evidence for an inverse relationship between ovarian hormones
and pugnacity. Furthermore, pugnacity was seen in fully spayed females
whereas others did not fight. All this was the basis for the conclusion
that aggressiveness in the female is a genetic trait not requiring hormonal activation. Unknown to Evans or to Greenberg and Noble was
the fact that aggression and sexual receptivity are negatively related in
at least a number of mammals (78-80). It may be that the entire subject
should be reinvestigated.
Neither the identity of the gonadal hormones produced by reptiles
nor their cellular origin has been established, but nothing in the extensive
morphological and endocrinological literature suggests any deviation
from the relationships in the other vertebrates. Interstitial tissue is present in the testes and, in most species, signs of activity in these cells are
correlated with the secondary sex characters. As in the pike, frog, and
birds, androgens may be present in the tubular lipid present following
the postspermatogenic metamorphosis of unshed germinal epithelium
(195).
Follicles containing follicular fluid develop in the ovary, as do cor-
215
incubation) seem to be quite definite and amenable to such treatment.
What appears to be an early stage in the evolution of parental behavior
is described by Dharmakumarsinhji (188) in his note on the copulatory
behavior of the marsh crocodile. The interest of Noble and Mason (185)
did not extend beyond the care of the eggs by the blue-tailed skink,
Eumeces fascicvtus, but they noted that one female in their series remained on the nest with the young for over 2 days after they were
hatched.
Many of the structural changes which follow gonadectomy and hormonal treatment are described by Dodd (123), by Forbes (135), and
by Kehl and Combescot (189) in their reviews. The assumption is justified that the relationship between the gonadal hormones and behavior
is also close. Direct evidence is provided by the increased aggressiveness
of turtles and lizards given testosterone propionate (190-194)
and by
the courtship and mating behavior displayed by gonadectomized male
and female Anolis carolinensis following treatment with estradiol dipropionate and testosterone propionate (186, 193, 194). Presumptive evidence for the relationship between the testes and the behavior of the
male is given by the correlation between the postspermatogenic steatogenesis and the autumnal sexuality of some vipers (195). Evans (178,
196) reported that ovarian hormone inhibits aggressiveness in female
Anolis carolinensis. Intact individuals are not aggressive toward other
females in the cage, but following ovariectomy they dominate females
and smaller males. Greenberg and Noble (182), on the other hand,
found no evidence for an inverse relationship between ovarian hormones
and pugnacity. Furthermore, pugnacity was seen in fully spayed females
whereas others did not fight. All this was the basis for the conclusion
that aggressiveness in the female is a genetic trait not requiring hormonal activation. Unknown to Evans or to Greenberg and Noble was
the fact that aggression and sexual receptivity are negatively related in
at least a number of mammals (78-80). It may be that the entire subject
should be reinvestigated.
Neither the identity of the gonadal hormones produced by reptiles
nor their cellular origin has been established, but nothing in the extensive
morphological and endocrinological literature suggests any deviation
from the relationships in the other vertebrates. Interstitial tissue is present in the testes and, in most species, signs of activity in these cells are
correlated with the secondary sex characters. As in the pike, frog, and
birds, androgens may be present in the tubular lipid present following
the postspermatogenic metamorphosis of unshed germinal epithelium
(195).
Follicles containing follicular fluid develop in the ovary, as do cor-