THE sexual behavior of the common

Transcription

1 The Effects of Acquaintance Between the Sexes on Sexual Behavior in White Leghorns* A. M. GUHL Kansas State University, Manhattan, Kansas THE sexual behavior of the common domestic chicken has received some attention during the past thirty years, with accelerated interest recently. The many reports present some difficulties in making critical comparisons of results. These lie chiefly in a confusion of terminology for behavior patterns and in a lack of an adequate description of the birds and of the conditions of the experiments. This is not an attempt to devise any standardization, but rather a presentation of some evidence that more experimental attention to certain details may be of value. With present trends to study the genetic background of sexual behavior (Wood-Gush, 1956; McDaniel and Craig, 1959; Siegel, 1959) the methods of measuring sex drive require careful consideration. There are many terms used for sexual behavior patterns, and there is some question as to which should be included as sexual, especially those which may serve as measures for sexuality. Skard (1937) listed male and female types of behavior and arranged them in an order of intensity. Her terminology was used as a basis for some subsequent studies (e.g., Guhl, Collias and Allee, 195). More recently Wood-Gush (195; 1956) elaborated on the patterns for the male, and included some (e.g., head-shaking, preening) which * Contribution number 301, Department of Zoology, Kansas Agricultural Experiment Station. The birds and facilities were provided by the Department of Poultry Husbandry. (Received for publication March 1, 1960) 10 might be questioned as sexual behavior or courting. He was interested in the various displays made by the males and concluded (1956) that a number of them are evoked by conflicts between two or more drives, although little experimental evidence was given. The question arises whether the research on sexual behavior of chickens has been adequate for a detailed classification of behavior patterns based on functions and/or conditions under which each may be evoked. It is common practice to place social behavior patterns into two major categories, agonistic and sexual behavior (parental behavior may also be considered as social). But even these are not distinctive. Successful matings are facilitated by the dominance relationships (Guhl, 19; 199) and submissiveness (Guhl, 1950). Both of these drives are augmented by gonadal hormones. The grasping of the comb or feathers of a hen by a cock is similar in total behavior to an attack by pecking, and the difference is largely the duration of the grasp with the beak by the cock. The complex behavior called a waltz (or wingflutter) occurs in aggression as well as in mating, and the threshold for this response may be lowered with androgen. Similarly, the "deep" or "sex-crouch" (Foreman and Allee, 1959) is associated with submission or receptivity (Guhl, 1950) and may be induced by estrogen. It is not unexpected therefore that conflicts may occur between agonistic and sexual drives as Wood-Gush (1956) postulates and demonstrates for waltzing.

2 SEXUAL BEHAVIOR 11 A number of factors known to influence the mating behavior of cocks have not been considered in some of the studies. It has long been known that mating occurs most frequently during the latter part of the day (Heuser, 1916; Philips, 1919; Upp, 192; Skard, 1937; Parker, McKenzie and Kempster, 190). Because some cocks do not mate with hens at random (so-called preferential mating, Philips, 1919; Warren and Kilpatrick, 1929; Skard, 1937), each male should be tested with a flock of females. It has been shown (Guhl, Collias and Allee, 195; Guhl and Warren, 196) that the frequency of mating by several cocks in a flock is directly related to social rank. To eliminate the effects of social dominance among males on sexual activity, this performance should be measured when a cock is alone with the hens. For convenience in testing several males, they may be caged in a battery between tests. Previous studies indicated that lack of previous experience influenced sexual performance of cocks. Similar indications were found by Fisher and Hale (1957) and Wood-Gush (195). If cockerels are reared apart from pullets, a conditioning period may be devised (Wood-Gush and Osborne, 1956; McDaniel and Craig, 1959). Cockerels tested with hens, which they fail to dominate, may show little, if any, sexual behavior (unpublished observations by Guhl). Among other factors which might be considered, there is the relative acquaintance between the males and females, which is the basic objective of this report. This factor is closely related to experience with the opposite sex. To test this factor it is necessary to use several males in each of contrasting situations to rule out marked individual variations in sex drive (Penquite, Craft and Thomson, 1930; Skard, 1937; Guhl, Collias and Allee, 195; Guhl, 1951; Wood-Gush, 195; Wood-Gush and Osborne, 1956). Since data on sexual approaches by the male, or courting, would be more quantitative than recording treadings only, it appears that a better estimate of sex drive could be obtained (Guhl, 1951). The objective of the present study was to determine which sexual behavior patterns and what conditions for testing might yield the most reliable and productive data on sexuality of cocks. MATERIALS AND METHODS Past experience has indicated that the waltz is relatively ineffective and that the rear approach is most effective for mating. Similar observations were reported by Wood-Gush (1956). Therefore these two approaches were recorded separately. All other types of courting were grouped into one category of approaches, in part for simplification and because they were of minor importance in eliciting the complete mating behavior sequence. That is, the objective was not to analyze all types of courting, but to obtain information for the development of a technique to measure the sexuality of cocks. In addition to matings (or treadings), and courting behavior, a cock might also be evaluated in terms of his acceptability to the hens. That is, by their responses to his courting. The female may react positively by giving the sex-crouch, or negatively by avoidance. The latter was recorded in two categories according to intensity, such as merely stepping aside or by the more intense escape of running away. Thus the data tabulated were in three categories of courting; one of treading; and three types of responses by the hens. Birds: The males and females were of the same strain of White Leghorns, hatched January 6, 1957, and were approximately 1 months old when the observations on sexual behavior were

3 12 A. M. GUHL IT h 1.5" -j 1.5' «36 9? lo- IO?? lo» 10?? la- 10?? lo» 10?? FIG. 1. The arrangement of pens and the distribution of hens and cocks. begun. The birds were brooded in batteries for four weeks and then moved to pens. The sexes were separated at eight weeks of age. From six and one half months to nearly 1 months they were used in another experiment during which all had some sexual experience. Prior to the present experiment the females were housed together in the large pen described below and the males were caged for some weeks in partial isolation. They were kept in laying batteries and could see and hear each other but could not engage in the usual physical contacts. Pens: A poultry house was divided into pens as shown in Figure 1. The large pen contained 0 females (four died before observations on sexual behavior started) and eight males. The cocks for this flock were placed into a laying battery of three tiers, with four on the bottom level and the others on the top level. The other half of the house was divided into four pens, each with 10 females and one male. The birds were placed at random into their respective pens or cages. At the beginning of the experiment the floor space per female was the same in each of the five pens. During the several tests the number of hens was further reduced by mortality to 3 in the large pen and to 36 in the small pens. All of the 12 males survived the complete experiment. Procedures: Table 1 is presented for convenient reference, since the procedures varied. There were five phases. The first was essentially to permit the hens in each flock to become well acquainted and to establish a social toleration characteristic of a matured social order (Guhl and Allee, 19), and for the cocks and hens in the small pens to become adjusted to each other socially and sexually. The contrasting situations sought in the second phase were (1) acquaintance between the sexes in one group, and strangeness in the other; and (2) differences in the intensity of the sex drive as related to the opportunity for its release or non-release (c./., Guhl, 1951). Presumably males may recognize hens as individuals (c./., Guhl and Warren, 196 for evidence of non-random mating). There may be a question as to how often, or long, a male must be exposed to hens before he may be considered acquainted with the females. Assuming that the methods used caused some qualitative differences, the terms "acquainted" or "unacquainted" will be used to designate such a variable. The sex drive of caged cocks may be dissipated within 10 minutes after release in a pen of hens (Guhl, 1951), and males penned with hens do display sexually throughout the day, i.e., the drive can be evoked as it attains a releasing level in the presence of a suitable stimulus object. However, mating occurs most frequently during the afternoons (Guhl and Warren, 196, and citations) and therefore the observations were made approximately between 2:30 and :30 p.m. (see dates in Table 1), for a total of 16 days. The order in which the five flocks were observed followed a regular rotation in all phases of the experiment. The large flock was observed for a total of 0 minutes, using four males per day. The order in which these eight males were released was rotated, using two from the bottom and two from the top cages. In the third phase the caged males were

4 SEXUAL BEHAVIOR 13 TABLE 1. An outline of the procedures and social conditions during the experiment Phase Dates (195) Conditions Social and sexual situations 1 1/2-3/26 (no observations on sex behavior) Large pen: penned o* & caged Small pens: penned () 1 cf penned 9 9 establish a stable peck order & c? not released 9 9 establish a stable peck order cf and 9 9 become adjusted /27-/23 /27-5/22 5/26-6/6 6/11-6/20 Large pen: c? c? released singly, 10 min./day, 16 days Small pens: cfd 1 observed 10 min./ day, 16 days Large pen: as in 2. 9 days. Small pens: ct tested with 9 9 in other small pens. 9 days. Large pen: Interchanged <?c? between top and bottom cages Small pens: as in 2. days Large pen: c?cf from small pens into bottom cages. days Small pens: cfc? from bottom cages into small pens. days 9 9 and c? unacquainted Sex drive not dissipated 9 9 and ct acquainted Sex drive dissipated As in and c? unacquainted Sex drive dissipated As in 2. As in 2 As in 2 As in 2 All observations for 10 minutes per male per day; 0 minutes for caged cf c? and for penned c? <?. Order of observations on males was rotated daily. Phases 3,, and 5; observations conducted as in 2, i.e., 10 min./day/cf. released as previouly, but the penned males were tested in small pens other than the "home" pen. During these observation periods the four penned males were caged in the middle tier of the laying battery and, following an order of rotation of males and pens, each spent 10 minutes with a small flock other than its "home" flock. After all four were tested, on a given day, each was returned to its "home" pen. There were nine days of observation in this phase. The situations in the large pen and the small pens were similar with respect to the degree of acquaintance between the males and the females; they differed in the intensity of the sex drive as the caged males were not exposed to hens prior to testing, whereas a penned male was caged for a maximum of 30 minutes prior to testing. Phase four was used to determine whether differences in sexual performance might be caused by the relative proximity of caged males to the females. Males were interchanged between the bottom and top decks of the laying battery. The tests were continued for the five flocks, as in phases two and three, for a total of eight days. By shifting these males, data were obtained for each male at each level, using data from phases three and four. Phase five was a check on individual differences between the cocks in the large pen and the small pens. The penned males were interchanged with the four males in the bottom tier of cages in the laying battery. The distribution of males into the small pens was random. The procedures were the same as in phase two, with a total of eight days of testing. Behavior patterns: A simplified chain of events in sexual behavior is given in Diagram 1 as a signal-response sequence. The various sexual approaches (courting) by the males are grouped in three categories as are the initial responses by the females. The letters in parentheses are symbols used in the tables and figures for presenta-

5 1 A. M. GUHL TABLE 2.--Summary of the basic data on mating behavior Phase Treatment of C? cf && nof 0 minute observations Behavior of cf d 1 Wf R A T Mean* Mean Mean Mean Responses of 9 9 C S E Mean Mean Mean 2 Caged Penned Caged Penned rotated Caged Penned Pen to cage Cage to pen f See Diagram 1 for code of behavior patterns. * Mean frequencies are for 0 minutes of observation on four males. tion of the data on the behavior patterns on which the attention was focused. RESULTS The basic data are summarized in Table 2 as means (rates) per 0 minutes of observation, i.e., for four males per day in each test situation. The means are used subsequently in the figures for comparative purposes. The observations show a pronounced difference in the frequency of behavior patterns between the caged and the penned males. Phase 1. During these two months the hens stabilized their peck orders and thereby social tension among the females as a complicating factor was reduced or eliminated. The effects of social status among hens on their sexual receptivity (Guhl, 1950) was not considered as important in the design of this experiment. Phase 2. A comparison of the sexual performance of the caged and penned males is made in Figure 2. The higher sex drive in the large pen is shown in the higher rates of courting (W, R, and A) by the males and receptivity as shown by the crouches (C) by the hens. The rear approach (R), which gives the best orientation for mounting, was highest among penned males and lowest among caged males. Waltzes (W), which give an inappropiate orientation, were the most common among caged males and nearly absent among penned males. Although the hens in the large pen were more receptive (higher rate of crouching), they avoided the males at high intensity (E) whereas the females in small pens avoided most often by merely stepping aside (S). Although the caged males trod (T) their hens nearly twice as frequently (Table 2) i Q. 20- < 10 CAGED [ 3 PENNED ES. lis. S3. S_ W R A T C S E BEHAVIOR OF MALE RESPONSE BY FEMALE FIG. 2. A comparison of the frequencies of sexual behavior patterns of caged and penned males during Phase 2. Waltz (W); rear approaches by males (R); other types of approaches (A); treadings (T); sexual crouches by females (C); low intensity avoidance by stepping aside (S); and high intensity avoidance as escape by running (E).

6 SEXUAL BEHAVIOR 15 Male Sexual approaches (W) waltz (R) from rear (A) other approaches DIAGRAM 1. SIGNAL-RESPONSE SEQUENCE Female >- (E) Escape by running (S) Avoids by stepping aside (C) Sexual crouch >Avoids (T) Mounting and treading Spreads tail and everts cloaca Ejaculation Steps off - May circle or waltz, Vents meet as the penned males, the rates were low in both situations. Furthermore, about one third of the treadings by the caged males were incomplete (vents failed to meet) whereas nearly all treadings by the penned males were completed. Highly receptive females in the large pen frequently showed avoidance of mounting and treading males by struggling to free themselves. Phase 3. The data obtained when penned males were rotated in strange flocks may be compared with those of caged males tested concurrently, and also with their own performance during the preceding phase 2. The behavior of the rotated males is compared with that of the caged males in Figure 3. Differences in sex drive are apparent between the caged and rotated males, although the performance of the penned males shows a shift from the previous record toward that of the caged males, e.g., there is a marked increase in the rate of waltzing (W), and the rear approaches (R) were proportionately less Moves tail to one side and everts cloaca ->- Stands, shakes, may run frequent than waltzes and other types (A) of courting (Figure ). Hens in the large pen were more receptive as shown by their rate of crouching (C), and the hens in the small pens showed an increase in avoidance behavior (Figure, S and E) which bo CO ^50 20 O,30 20 < cc\0 W i R BEHAVIOR OF MALE CAGED S Ek a. PENNED, ROTATED A T C S E RESPONSE OF FEMALE FIG. 3. A comparison of the frequencies of sexual behavior patterns of caged and penned-rotated males during Phase 3. Symbols the same as in Figure 2.

7 16 A. M. GUHL PENNED,50 E3 PENNED, ROTATED i0 J O30 J i= I o < im r-rsin^l W R A T C S E BEHAVIOR OF MALE RESPONSE BY FEMALE FIG.. A comparison of the frequencies of sexual behavior patterns of penned males during Phase 2 with the same males in Phase 3 when rotated in the small pens. Symbols the same as in Figure 2. approximated that in the large pen (Figure 3). For some reason the caged males trod (T) more frequently than in phase 2, but the rates in the small pens showed a minor difference (Figure ). It appears that strange hens stimulated the pennedrotated cocks, but that the hens reacted adversely to strange males. Phase. To determine whether the relative proximity of the caged males to the hens on the floor influenced performance, the data from phases 3 and were combined as to top and bottom cages. The 3 0 o *30 K Ul a 20 El 1 TOP CAGES 3 BOTTOM CAGES 1 ^rrei W R A T C S E BEHAVIOR OF MALE RESPONSE OF FEMALE FIG. 5. The frequencies of sexual behavior patterns of males when caged in the top of the battery with their performance when in the bottom tier of cages, Phases 3 and. Symbols the same as in Figure 2. data showed some marked differences between individual males which were quite consistent whether in top or bottom cages. Therefore these data were pooled as to top and bottom levels since each individual had occupied each level. The rates are given in Figure 5 and show only minor differences. All eight males could see and hear the hens. Some females jumped, or flew, to the feed troughs of the cages on both levels, which seemed to stimulate the cocks. Phase 5. When the males in the small pens were interchanged with those in the bottom cages they were exposed to different hens, as were the formerly caged males. Other changes would include the type of footing, i.e., wire floors of cages or litter on the floor of the pens; restricted movement or greater freedom of activity; and no physical contact with hens or free contact. Approximately hours were given for these adjustments prior to making any observations on sexual behavior. The results are given in Table 2, and in Figures 6 and 7 for a comparison of performance in phases and 5. Figure 6 shows the changes in behavior of the same E0 30,20 < * 10 SEL CAGED S PENNED W R A T C S E. BEHAVIOR OF MALE s_ RESPONSE OF FEMALE FIG. 6. The frequencies of sexual behavior patterns of males when in the bottom cages during Phase with their performance when penned with hens during Phase 5. Symbols the same as in Figure 2.

8 SEXUAL BEHAVIOR 17 males when caged and when penned, and Figure 7 shows the modified behavior when penned males were caged. It is possible that the psycho-physiological conditions of the males in phase carried over into phase 5. This is suggested by the greater sexual activity of the pen-to-cage males (in 5) than occurred in any other phase by cage males (Table 2) and by the fact that the more effective rear approach (R) and treadings (T) were at a rate that exceeded any other caged males. There is also the suggestion that the effect of strange females (noted in phase 3) may have been involved. No tests were made to compare the sexuality of the individuals (Guhl, 1951) in these two sets of males, and it may be that the formerly penned males had a higher sex drive irrespective of social situations. Neither was the receptivity of hens in the large flock compared with that in small flocks. Of particular interest as to the objective of this experiment are the changes in behavior patterns in terms of frequencies which are apparent in Figures 6 and 7. Caged males and their females were more active sexually than were males penned with females. Waltzes (W) were the most frequent type of courting for caged males, and the rear approach for penned males, irrespective of previous situations. Hens tended to show a higher intensity (E vs. S) of avoidance behavior toward caged cocks, and also crouched (C) more readily than did those in small pens. Signal-response sequence: As given in Figure 2, the signal-response sequence in mating behavior usually begins with some form of courting by the male. It has been suggested above that the type of approach with regard to orientation of the male toward the female, may bear some relation to the completion of the sequence. And since social situations affect the frequency of the several categories of courting, social S0 o 30 (E UJ Q. tu H < a: 10 H a W R A BEHAVIOR OF MALE PENNED!E3 CAGED i I 111 J T C S E sm RESPONSE OF FEMALE FIG. 7. The frequencies of sexual behavior patterns of males when penned with hens during Phase with their performance when in the bottom cages during Phase 5. Symbols the same as in Figure 2. situations may be important in the efficiency of mating behavior. It should be recalled, however, that in this experiment the social stress between females was at a minimum and that males were not in competition with each other, i.e., what social stress there may have been was between the sexes. The categories of behavior patterns which initiated any sexual behavior are given in Figure as frequencies for caged, penned, and penned-rotated males. The mean frequencies for caged males are from the data during phases 2 through 5, for penned males from phases 2,, and 5, and for penned-rotated males from phase 3 only. It may be concluded that waltzes (W) were most common when the cock and the hens were unacquainted, because this behavior all but disappeared when the males were penned and acquainted with the hens. However, waltzes were also associated with the level of sex drive, because the penned-rotated males showed a lower frequency than the caged males although the rate was higher than with acquainted hens. There is a strong indica-

9 1 A. M. GUHL 3 z o cr UJ 0- cn UJ i- < cr CAGED fs PENNED ffl PENNED, ROTATED J I 1 J W R A C BEHAVIOR PATTERN INITIATING SEQUENCE FIG.. A comparison of the frequencies of sexual behavior patterns which initiated stimulus-response sequences when males were caged during Phases 2-5, when penned with hens during Phases 2,, 5, and when penned and rotated in the small pens during Phase 3. Symbols the same as in Figure 2. tion that the waltz, or wingflutter, should be considered as a displacement activity (Armstrong, 197, p. 106; Thorpe, 19, p. ; Tinbergen, 1952). The impression was given that the cock waltzed with strangers because the attack (strange birds usually settle their dominance relations at their first meeting) and sex drives were in conflict, or when hens were unresponsive. These conditions agree with those stipulated by Bastock, Morris and Moynihan (1953) for the occurrence of displacement activities. On the other hand the rear approach (R) was used most frequently by the penned males with their acquainted females. In contrast, this type of courting was used the least often by the caged males. The penned-rotated (Table 2, phase 3; Figure ) males showed an intermediate performance in all respects to these categories. Neither the waltz nor the rear approach were the most frequent. Several factors may be related to this behavioral difference. Habits in the "home" pen may have carried over to the test situation since a maximum of only 30 minutes elapsed between removal from the "home" pen and the introduction to strange hens; they had a lower level of sex drive as did the females; and the strangers were only 10 in number (whereas there were approximately 36 strangers with the caged males) and some progress in acquaintance may have developed. It is a common observation that hens in mating flocks do not initiate sexual behavior, although hens in laying flocks (without a cock) may crouch readily when one enters the pen rather suddenly; and very dominant hens sometimes evoke a submissive crouch when threatening certain of their subordinates. The frequencies of crouching (C) in Figure show a similar response to the release of a cock. The rate of crouching has been used as an indication of receptivity (Guhl, 1950). As the figure shows, crouching was characteristic of the hens in the large flock. There was a single observation of crouching in the small pens when males were rotated. It should be recalled that the data given in Figure are for crouches initiated by the female in response to the release of a cock and not to courting. Thus it appears that waltzes and crouches have a relation to both sexual and social dominance behavior. This aspect of these behavior patterns will be discussed later. The stimulus-response sequences may be terminated at any link in the chain of behavior patterns. The male's sex drive may be reduced at various levels of satiation or a low level might be characteristic of an individual (Guhl, 1951). The usual break in the sequence is caused by an avoiding reaction by the female. The question arises whether the social situations between the sexes exert any influence on the number of sequences which terminate in coition. To state it another

10 SEXUAL BEHAVIOR 19 way, which of the behavior patterns that initiate sexual behavior are most likely to run the full sequence and therefore be the most effective in reproduction? Figure 9 gives the percentage of treadings which result from each of the three categories of male approaches and of crouching, for each type of test. The data are taken from the same phases of the experiment as those in Figure. The number of observations are given in the figure as fractions, i.e., the numerator is the actual number of treadings and the denominator the number of times the initiating behavior pattern was observed. These data may be useful here, because the activity in the small flocks was too low to make percentages strictly comparable. For example, only one crouch in the penned-rotated test was observed and a percentage of 100 would be misleading. The results are enlightening. Completed signal-response sequences which were initiated by the rear approach (R) exceeded (.% to 20.5%) the other types of approaches, and the waltzes resulted in the fewest treadings (0% to 2.6%). It has been shown that the waltz was the most frequent form of courting by caged males and the rear approach by penned males. Although the caged males trod the hens more frequently than the penned males (Table 2, T) they spent more energy in courting and that in an ineffective manner (W and A in Table 2). Crouching was relatively common (9%) as a "sex invitation" in the large pen but only 7 out of 521 terminated in treading (Figure 9). Thus 7 crouches failed to result in treading although the sexual crouch is a strong stimulus for the male to mount (Fisher and Hale, 1957). It may be concluded the sexes synchronized best when the male approached from the rear. Guhl (199) concluded that the passive dominance of the male over the female in a well UJ ir I-,20 15 Mo Id H & o > < X o I 1 CAGED E3 PENNED 0 PENNED, ROTATED II Vt _0_I75 5 t77l W R A C I&L BEHAViOR PATTERN INITIATING SEQUENCE FIG. 9. The percentage of signal-response sequences initiated by each of the sexual behavior patterns which culminated in treading. The fractions present the number of observations. Symbols the same as in Figure 2. integrated flock facilitates mating. The waltz has an element of threatening, whereas the rear approach is more passive; it may have a "surprise" effect which stimulates the hen to crouch; and the male is oriented for immediate mounting. DISCUSSION In experiments involving libido measurements of cocks, a reliable test situation is paramount. This study was designed as an attempt to refine methods of testing and to obtain information which may reduce the time, and simplify procedures, for testing a large number of males. One of the major problems encountered previously was the acquaintance between the sexes. Associated with this problem was that of handling the cocks. If the males could be maintained in a battery between tests, testing would be facilitated. A number of questions are

11 20 A. M. GUHL relevant. Caging males makes it possible to test many males and eliminates a number of other problems, but how would the results compare with performance in a breeding pen? Must the caged males be in proximity of the females? Since courtings are much more frequent than treading, which type of approach behavior, in addition to treading, may be most reliable in the measurement of sexuality? The results indicate that cocks penned singly with a flock of hens may yield data similar to actual performance in a breeding pen, but more data may be obtained per unit of testing time if the males are caged and released singly for short periods. In the latter situation both sexes show a higher level of sex drive. The waltz, which is the most striking display by the male, is frequent when testing cage males and is all but absent when cocks remain with acquainted females. This display has both agonistic and sexual elements. Since the rear approach is the most effective in completing the mating behavior sequence, the indications are that this measure of sex drive is more reliable than the waltz, and may be used along with treading rates to evaluate libido. Despite the fact that penned males may give the most reliable data, caging of males for testing has definite advantages. Certain modifications might be made which have not been considered in the experiment reported here, but may be deduced from this report. The cocks were caged within the pen of the females. Holding cocks in quarters away from the hens may only serve to increase strangeness. A test of this factor was not included in the present experiment, because previous experience has indicated that this is true. Acquaintance might be increased by permiting each caged male to run with the hens for a half to one day prior to testing, depending on the number of males used with each flock of hens. Whatever method one chooses to use in measuring sex drive in males, the results of this experiment show that among several factors to consider, the relative acquaintance between the sexes influences the type of data obtained. REFERENCES Armstrong, E. A., 197. Bird Display and Behaviour. London: Lindsay Drummond. Bastock, M., D. Morris and M. Moynihan Some comments on conflict and thwarting in animals. Behaviour, 6: 66-. Fisher, A. E., and E. B. Hale, Stimulus determinants of sexual and aggressive behavior in male domestic fowl. Behaviour, 10: Foreman, D., and W. C. Allee, A correlation between posture stance and outcome in paired contests of domestic hens. Ani. Behav. 7:10-1. Guhl, A. M., 19. Unisexual mating in a flock of White Leghorn hens. Trans. Kansas Acad. Sci. 51: Guhl, A. M., 199. Heterosexual dominance and mating behavior in chickens. Behaviour, 2: Guhl, A. M., Social dominance and receptivity in the domestic fowl. Physiol. Zool. 23: Guhl, A. M., Measurable differences in mating behavior of cocks. Poultry Sci. 30: Guhl, A. M., and W. C. Allee, 19. Some measurable effects of social organization in flocks of hens. Physiol. Zool. 17: Guhl, A. M., N. E. Collias and W. C. Allee, 195. Mating behavior and the social hierarchy in small flocks of White Leghorns. Physiol. Zool. 1: Guhl, A. M., and D. C. Warren, 196. Number of offspring sired by cockerels related to social dominance in chickens. Poultry Sci. 25: Heuser, G. F., A study of the mating behavior of the domestic fowl. Thesis, Master of Agriculture degree, Graduate School, Cornell University. McDaniel, G. R., and J. V. Craig, Behavior traits, semen measurements and fertility of White Leghorn males. Poultry Sci. 3: Parker, J. E., E. F. McKenzie and H. L. Kempster, 190. Observations on the sexual behavior of New Hampshire males. Poultry Sci. 19: Penquite, R., W. A. Craft and R. B. Thomson, Variation in activity and production of spermatozoa by White Leghorn males. Poultry Sci. 9:

12 SEXUAL BEHAVIOR 21 Philips, A. G., Preferential mating in fowls. Poult. Husbandry J. 5: Siegel, P. B., Evidence of a genetic basis for aggressiveness and sex drive in the White Plymouth Rock cock. Poultry Sci. 3: Skard, A. G., Studies in the psychology of needs: Observations and experiments on the sexual need of hens. Acta Psychol. 2: Thorpe, W. H., 19. The modern concept of instinctive behaviour. Bull. Ani. Behav. 1:1-12. Tinbergen, N., Derived activities; their causation, biological significance, origin and emancipation during evolution. Quart. Rev. Biol. 27: Upp, C. W., 192. Preferential mating in fowls. CHANG (1955) reported the lowering of the blood hemoglobin of chicks due to free gossypol feeding and postulated that free gossypol in the diet leads to interference with the synthesis of the proteins of the blood in these chicks. In view of the useful information that has been obtained in recent years using the electrophoresis technique in the study of normal and pathological sera, an experiment was planned to study the electrophoretic patterns of serum samples obtained from birds fed a normal diet, as well as from birds fed free gossypol in the diet. An electrophoresis cell using filter paper strips, as originally designed by Durrum (1950) and marketed by Spinco, was employed. Later it was discovered that 1 Present address: Dept. of Botany, Washington University, St. Louis, Missouri. Poultry Sci. 7: Warren, D. C, and L. Kilpatrick, Fertilization in the domestic fowl. Poultry Sci. : Wood-Gush, D. G. M., 195. The courtship of the Brown Leghorn cock. Brit. J. Ani. Behav. 2: Wood-Gush, D. G. M., The agonistic and courtship behaviour of the Brown Leghorn cock. Brit. J. Ani. Behav., : Wood-Gush, D. G. M., 195. Genetic and experiential factors affecting the libido of cockerels. Proc. Roy. Soc. Edinburgh, 27: 6-^. Wood-Gush, D. G. M., and R. Osborne, A study of differences in the sex drive of cockerels. Ani. Behav. : Paper Electrophoresis and Albumin/Globulin Ratios of the Serum of Normal Chickens and Chickens Fed Free Gossypol in the Diet R. NARAIN, 1 C. M. LYMAN, C. W. DEYOE AND J. R. COUCH Departments of Poultry Science and Biochemistry and Nutrition, Texas A&M College System, College Station, Texas (Received for publication Match 1, 1960) the resolution of the globulins of chick serum is very poor on filter paper. More serum samples were obtained from birds used in a study of the effect of protein level on free gossypol tolerance, and these samples were analyzed chemically for the albumin and globulin content and the albumin/globulin ratio. An opportunity was also available here to study the changes in these components on changing the protein level of the diet. EXPERIMENTAL PROCEDURE In the first experiment two groups of White Leghorn chicks, containing 20 chicks per group were fed a practical (soybean-corn) type of chick diet as used in our laboratory. The first group served as a control, while 0.10% free gossypol was added in the form of pigment glands to the diet of the second group. These