著者

森戸 義一

出版者

The Japanese Society for Animal Psychology

雑誌

動物心理 (ISSN:18836275)

巻号頁・発行日

vol.4, no.1, pp.8-36, 1938-07-15 (Released:2009-10-13)

---

In the study hitherto made of cocks' crowing, it was understood that results obtained from various experiments can be explained to dep nd upon function of a hormone and especially it came to be known that its mechanism c nsists in the fact that certain periodical stimulus is given to internal organs by a testicle-hormone. So I made some experiments on same cocks, in wich the hormone activity was artificially weakened or to which a hormone drug was injected Now I will report here the results of these experiments.1. Even though one of a cock's testicles is removed in the chicken stage, its crowing behaviour presents itself as it grows up. But it takes a great many days for the crowing-on an average 87 days more than in normal cocks to give the first utterance and 3 days more for the normal utterance.2. Though is imperfect, it gradually becomes regulated. But the time-duration of crowing is generally short in any case.3.The frequen y is generally small and it is reduced to less t an half of that in normal cocks.4. The number of days required for their utterance is very large, while that for the normal utterance is comparatively small. The former results from the development of their bodily and vocal organs, and the latter from their learning to crow.5. The above-mentioned changes take place on account of their onesided testicle and the fact that their inner function was reduced to less than half of that in normal cocks.6. Every crowing at the early dawn uttered by animals with a single testicle is not constant or in some cases it is not uttered at all.7. The frequency of their crowing decreases extremely, and it cannot be observed that it comes to increase as the crowing is repeated in regular order., as is se n in normal cocks.8. When the cocks which do not crow at the early dawn or constantly are treated with the hormone, they all come to be able to utter a crowing.9. Though in this case the number of times of the crowing shows no increase, yet it is far larger than before.10. In the course of development which takes place in those injected with a hormone of the opposite sex we can see that it takes a great many days for the first utterance, but it is given earlier than that in those whose single testicle is removed in the stage of chickens. So it is certain that the grade of inhibition done to the crowing by an application of a hormone of the opposite sex ranks between that in the case of normal cocks and that in the case of those wi h a single tisticle.11. The crowing of the cocks treated with a hormone of the opposite sex is imperfect in the vocal note, short in time duration, and generally seems to be week in power.12. In those supplied with a hormone of the opposite sex, the crowing at the early dawn is irregular among the individuals.13. The above changes are due to the impediment given to the functions or periodical vocal utterance in the male sex.14. The pr sence of testicle is an indispensable condition for the cock's crowing without which it can never be realized.15. When a hormone of the same sex is supplied to the cocks whose natural crowing behaviour has been changed through an inhibitory effect given by a hormone of the opposite sex. They came to regain the function assigned to the male sex.16. In this case the more powerful a hormone of the same sex is, the greater becomes its effect.17. When one of the testicles of a grown-up cock is removed. it stops crowing for a few days but later it comes to crow again. In the latter case the frequency is reduced to less than half of that in normal individuals.18. It is quite impossible for grown-up cocks with a single testicle to utter a crowing at the early dawn. Even if they crow now and then, it is very difaicult for them to tell the exact time.

著者

森戸 義一

出版者

The Japanese Society for Animal Psychology

雑誌

動物心理 (ISSN:18836275)

巻号頁・発行日

vol.3, no.1-2, pp.1-41, 1936-10-20 (Released:2010-01-28)

---

It is the principal aim of my experience to examine what mechanism the cocks' crowing at the early dawn is based on.For this purpose a couple of genuine white leghorns was chosen, from whom were gained more than 20 eggs, and they were hatched.Among them only the cocks numbering 12 were bred and used for the experimental material. These 12 cocks were slowly separated from one another until each one of them was bred by itself. Putting these individuals under the entirely same condition from the time of chickens, I examined the results of the following three experiments.1) Changes of vocal sound as each individual becomes older.2) Comparison in normal crowing between separation and cohabitation.3) Comparison in normal crowing at the early dawn between the normal cocks and the deaf cocks.Now, this article is the conclusion which I have arrived at in the experiments.By the way the deaf cocks are those which when 200 days passed after their hatch were bored a hole in the tympanum of their ears after complete sterilization and the holes were filled with guttapercha used in dental surgery and then their burr edges were closed with three stiches.1. Under the same experimental condition, the age when the cocks utter for the first time is 142 days on the average.2. Each of the cocks does not give its first utterance except in the morning. The first utterance can never be heard in the afternoon, still less in the evening.3. The sound of voice in the first utterance is divided into a voiceless and a voiced sound. Then a change takes place when they begin to crow in normal note.4. The note of first utterance is generally “kc : ”, while some of the cocks rarely utter in the note of “kc : c” and others in “kcc : c”.5. The note in normal crowing is “kcke kc kcu.” The sooner the cocks can utter these two underlined assimilated sounds, the smaller is the number of times of their change of note from the first utterance to normal crowing. The smaller is the number of times of vocal change, the more rapid is its process.6. The days tend to become more and more from the first utterance to normal crowing, the more are the days to be spent between the hatching and the first utterance.7. The more are the days from the first utterance to the normal crowing, the smaller is the number of times of vocal change.8. The days to be spent from the hatching to the first utterance, and the days from the first utterance to normal crowing ; the gaining in weight and the lengthening of the cockscomb-between these things there can be seen no remarkable relation. Neither the cocks' growth by the day nor the gaining in their weight has anything to do with the number of times of normal crowing. The hours of normal crowing, however, have a close connetion to the growth by the day.9. As for the number of times of normal crowing in a day, there are some individual differences among the cocks coming out of the same parents, but the number of times that each one of them crows for itself is almost constant. The length of daytime, however, has a great influence upon the number of times of normal crowing. For this reason the number in June whose days are long, is larger than that of November. But the number of times at the early dawn is not related to any season. Another thing is that on the whole the number of times is distinctly smaller in cohabitation than in separation.10. The number of times of normal crowing is small for a certain while before and after noon, and the number becomes smaller and smaller towards evening. In the evening the cocks utter frequent crows periodically at a single time, and the stop crowing at sunset. These frequent crows are uttered at the same hours in case of “brother-cocks”.