"Siamese Fighting Fish (Betta splendens)
While doing research on the aggressive threats and other social behaviors of Betta splendens (Baenninger, 1966; Baenninger, 1984), I observed yawning during encounters with conspecifics and with mirror images but not in their solitary behavior. For this reason I hypothesized that yawning would occur primarily when conspecifics were visible, and particularly in aggressive, intruder-resident interactions. Myrberg (1972) described yawning of bicolor damselfish, Eupomacentrus partitus, and discovered that it accompanied transitions between various social behaviors, particularly agonistic responses and nest entrances and exits.
Experiments and Observations All fish were purchased froin a commercial supplier and were housed in Miter glass aquaria for 1 mo before observations. They were observed from behind a screen during the light-on phase of a 12-hr light cycle. They were fed a small amount of frozen brine shrimp daily. Aquaria were cleaned every 4 days. Yawning by 15 isolated fish was observed for twenty 1-hr intervals in the light-on portion of their daily light-dark cycles. During these sessions the observer viewed fish under 15-W white illumination through holes cut in opaque material that prevented fish from seeing the observer. Under these circumstances only a single yawn was observed. This constitutes a rate of 0.003 yawn/fish-hour. The frequency of yawning increased greatly when 7 pairs of male Siamese fighting fish were observed while separated by clear Plexiglas partitions. Of the 14 fish, 12 yawned between one and seven times during a single 1-hr observation that followed 24 hr of visual isolation. There were 41 yawns during 14 fish-hours, a rate of 3.0 yawns/fish-hour. The 12 fish that yawned did so an average of 3.5 times per hour. There was no evidence of yawning contagion in these observations; a minute-by-minute analysis of responses did not show any temporal pattern of yawns, either between or within the protagonisis. That is, in only one instance did members of a pair both yawn during the saine or successive minutes, but 2 other fish were observed to yawn repeatedly during successive minutes. These multiple yawns were not reciprocated by the fish on the other side of the transparent partition.
After these paired observations every fish was again isolated for 24 hr, after which each pair was again observed for 1 hr while separated by clear Plexiglas. This time 3 (different) fish failed to yawn, and 27 yawns were recorded, a mean of 2.5 yawns for each fish thai yawned and a rate of 1.9 yawns/fishhour. This decrease between the first and the second observation was significant by a sign test (p < .05, two-tailed). If yawning were associated with absence of stimulation or lack of stimulus change, one might expect the rAponse to increase after isolation and repeated exposure to the saine conspecific. Instead, like the biting response in repeated pair encounters of this species (Baenninger, 1984), the pattern 1 am referring to as yawning appears to wane.
The possibility of an association between yawning and biting was studied in a third set of observations. Novel pairs were formed by placing 5 individual male Bettas in the 12liter aquaria of 5 resident males which had been living in thern alone for 1 wk. The yawning and biting responses of both residents and intruders were counted during the first hour together; after 23 hr together, these responses were again counted for 1 tir. During the first hour the two pairs performed 153 bites and 60 yawns (6.0 yawns/fish-hour). After 24 hr there were 92 bites, but only 8 yawns (0.75 yawn/fish-hour). In one pair the intruder was severely damaged by the resident and showed neither biting nor yawning responses. Putting pairs of fish together was necessary in order to measure biting, but because of the aggressiveness of these fish toward conspecifics, this study was run with a small number of subjects. It appears that both biting and yawning responses wane with continued exposure to the same conspecific and that actual combat increases the initial yawning rate, compared with the rate when fish have only visual contact. In the final study, 14 pairs of naive male fish, isolated in 1-liter aquaria, were visually exposed Io each other. Their yawning responses to a single conspecific in 1 hr were recorded. Fish were then isolated again, but a mirror was placed against the aquaria of seven pairs (14 fish) so that each subject could view its own image instead of a conspecific; the rernaining seven pairs saw neither mirrors nor fish. Twenty-four hours later the yawning responses to the original pair mernber were again counted, This procedure was then repeated after 48 hr. Under these circumstances, with the mirror present for two 24-hr intervals, there was only slight waning of yawning responses. There were 55 yawns in response to pair members during the initial hour (3.9/fish-hour), 64 after 24 hr of mirror viewing (4.6/fish-hour), and 43 after a second 24-hr period of mirror viewing (3. 1 /fish-hour). The no-mirror control pairs essentially replicated the results of the second study, by showing clear evidence of a waning of yawns over repeated exposure to a conspecific: Initially there were 65 yawns (4.5/fishhour); 24 hr later there were 29 (2. 1 /fish-hour); and during the final pair encouriter 48 hr later, there were 24 yawns (1.7/ fish-hour). Having a mirror present during isolation from conspecifics appears to counteract the waning of yawning that normally occurs in repeated pair encounters.
The rate of yawning by members of this species is dramatically increased by the presence of a single conspecific. There were 300 times as many yawns/hour when fish were in visual contact with a conspecific. During actual combat the rate of yawning was again doubled initially, although it waned after prolonged fighting, perhaps due to physical exhaustion. Presence of a mirror while fish were isolated prevented waning of yawns in visual pair encounters that were separated by 24-hr intervals. The possibility that yawning is an aspect of agonistic threatening in this species is clear, but it has not previously been documented (Simpson, 1968)."
From Some comparative aspects of yawning in Betta splendens, Homo sapiens, Panthera leo, and Papio sphinx
Tawk amongst yourselves.
While doing research on the aggressive threats and other social behaviors of Betta splendens (Baenninger, 1966; Baenninger, 1984), I observed yawning during encounters with conspecifics and with mirror images but not in their solitary behavior. For this reason I hypothesized that yawning would occur primarily when conspecifics were visible, and particularly in aggressive, intruder-resident interactions. Myrberg (1972) described yawning of bicolor damselfish, Eupomacentrus partitus, and discovered that it accompanied transitions between various social behaviors, particularly agonistic responses and nest entrances and exits.
Experiments and Observations All fish were purchased froin a commercial supplier and were housed in Miter glass aquaria for 1 mo before observations. They were observed from behind a screen during the light-on phase of a 12-hr light cycle. They were fed a small amount of frozen brine shrimp daily. Aquaria were cleaned every 4 days. Yawning by 15 isolated fish was observed for twenty 1-hr intervals in the light-on portion of their daily light-dark cycles. During these sessions the observer viewed fish under 15-W white illumination through holes cut in opaque material that prevented fish from seeing the observer. Under these circumstances only a single yawn was observed. This constitutes a rate of 0.003 yawn/fish-hour. The frequency of yawning increased greatly when 7 pairs of male Siamese fighting fish were observed while separated by clear Plexiglas partitions. Of the 14 fish, 12 yawned between one and seven times during a single 1-hr observation that followed 24 hr of visual isolation. There were 41 yawns during 14 fish-hours, a rate of 3.0 yawns/fish-hour. The 12 fish that yawned did so an average of 3.5 times per hour. There was no evidence of yawning contagion in these observations; a minute-by-minute analysis of responses did not show any temporal pattern of yawns, either between or within the protagonisis. That is, in only one instance did members of a pair both yawn during the saine or successive minutes, but 2 other fish were observed to yawn repeatedly during successive minutes. These multiple yawns were not reciprocated by the fish on the other side of the transparent partition.
After these paired observations every fish was again isolated for 24 hr, after which each pair was again observed for 1 hr while separated by clear Plexiglas. This time 3 (different) fish failed to yawn, and 27 yawns were recorded, a mean of 2.5 yawns for each fish thai yawned and a rate of 1.9 yawns/fishhour. This decrease between the first and the second observation was significant by a sign test (p < .05, two-tailed). If yawning were associated with absence of stimulation or lack of stimulus change, one might expect the rAponse to increase after isolation and repeated exposure to the saine conspecific. Instead, like the biting response in repeated pair encounters of this species (Baenninger, 1984), the pattern 1 am referring to as yawning appears to wane.
The possibility of an association between yawning and biting was studied in a third set of observations. Novel pairs were formed by placing 5 individual male Bettas in the 12liter aquaria of 5 resident males which had been living in thern alone for 1 wk. The yawning and biting responses of both residents and intruders were counted during the first hour together; after 23 hr together, these responses were again counted for 1 tir. During the first hour the two pairs performed 153 bites and 60 yawns (6.0 yawns/fish-hour). After 24 hr there were 92 bites, but only 8 yawns (0.75 yawn/fish-hour). In one pair the intruder was severely damaged by the resident and showed neither biting nor yawning responses. Putting pairs of fish together was necessary in order to measure biting, but because of the aggressiveness of these fish toward conspecifics, this study was run with a small number of subjects. It appears that both biting and yawning responses wane with continued exposure to the same conspecific and that actual combat increases the initial yawning rate, compared with the rate when fish have only visual contact. In the final study, 14 pairs of naive male fish, isolated in 1-liter aquaria, were visually exposed Io each other. Their yawning responses to a single conspecific in 1 hr were recorded. Fish were then isolated again, but a mirror was placed against the aquaria of seven pairs (14 fish) so that each subject could view its own image instead of a conspecific; the rernaining seven pairs saw neither mirrors nor fish. Twenty-four hours later the yawning responses to the original pair mernber were again counted, This procedure was then repeated after 48 hr. Under these circumstances, with the mirror present for two 24-hr intervals, there was only slight waning of yawning responses. There were 55 yawns in response to pair members during the initial hour (3.9/fish-hour), 64 after 24 hr of mirror viewing (4.6/fish-hour), and 43 after a second 24-hr period of mirror viewing (3. 1 /fish-hour). The no-mirror control pairs essentially replicated the results of the second study, by showing clear evidence of a waning of yawns over repeated exposure to a conspecific: Initially there were 65 yawns (4.5/fishhour); 24 hr later there were 29 (2. 1 /fish-hour); and during the final pair encouriter 48 hr later, there were 24 yawns (1.7/ fish-hour). Having a mirror present during isolation from conspecifics appears to counteract the waning of yawning that normally occurs in repeated pair encounters.
The rate of yawning by members of this species is dramatically increased by the presence of a single conspecific. There were 300 times as many yawns/hour when fish were in visual contact with a conspecific. During actual combat the rate of yawning was again doubled initially, although it waned after prolonged fighting, perhaps due to physical exhaustion. Presence of a mirror while fish were isolated prevented waning of yawns in visual pair encounters that were separated by 24-hr intervals. The possibility that yawning is an aspect of agonistic threatening in this species is clear, but it has not previously been documented (Simpson, 1968)."
From Some comparative aspects of yawning in Betta splendens, Homo sapiens, Panthera leo, and Papio sphinx
Tawk amongst yourselves.
Anybody got a sparknotes version on that. 
