Heart rates of sea snakes diving in the sea

Heart rate reduction during voluntary deep diving in free-ranging loggerhead sea turtles

“…The present results on the flipper stroke rate differed from those of previous studies which indicated that heart rate increased upon the onset of underwater exercise in free-ranging sea snakes ( Heatwole et al, 1979 ) and captive experiments on sea turtles ( Williams et al, 2019 ; Okuyama et al, 2020 ). In sea turtles, heart rate is thought to elevate upon the onset of underwater exercise and increase linearly with exercise ( Okuyama et al, 2020 ) because their major oxygen stores are their lungs ( Lutz and Bentley, 1985 ) and they need to transport oxygen to muscles from their lungs.…”

“…However, specifically in deep dives under natural conditions, the variation of heart rates in free-ranging aquatic reptiles has not been examined. Although field studies on aquatic reptiles have shown a slight reduction in heart rate during diving, these studies were conducted on species that inhabit shallow water, such as freshwater crocodiles ( Seebacher et al, 2005 ), American alligators ( Smith et al, 1974 ) and sea snakes ( Heatwole et al, 1979 ), or on leatherback sea turtles during the interesting interval during which they dived to relatively shallower levels than the levels to which they dive normally during foraging periods ( Southwood et al, 1999 ). Among marine reptiles, sea turtles have outstanding diving abilities.…”

Heart rate reduction during voluntary deep diving in free-ranging loggerhead sea turtles

“…The present results on the flipper stroke rate differed from those of previous studies which indicated that heart rate increased upon the onset of underwater exercise in free-ranging sea snakes ( Heatwole et al, 1979 ) and captive experiments on sea turtles ( Williams et al, 2019 ; Okuyama et al, 2020 ). In sea turtles, heart rate is thought to elevate upon the onset of underwater exercise and increase linearly with exercise ( Okuyama et al, 2020 ) because their major oxygen stores are their lungs ( Lutz and Bentley, 1985 ) and they need to transport oxygen to muscles from their lungs.…”

“…However, specifically in deep dives under natural conditions, the variation of heart rates in free-ranging aquatic reptiles has not been examined. Although field studies on aquatic reptiles have shown a slight reduction in heart rate during diving, these studies were conducted on species that inhabit shallow water, such as freshwater crocodiles ( Seebacher et al, 2005 ), American alligators ( Smith et al, 1974 ) and sea snakes ( Heatwole et al, 1979 ), or on leatherback sea turtles during the interesting interval during which they dived to relatively shallower levels than the levels to which they dive normally during foraging periods ( Southwood et al, 1999 ). Among marine reptiles, sea turtles have outstanding diving abilities.…”

New chromosome-scale genomes provide insights into marine adaptations of sea snakes (Hydrophis: Elapidae)

“…Selection on these genes might contribute to various aspects of the bimodal respiration of sea snakes. The respiratory tissues of the trachea and right lung extend almost the length of the sea snake body and the perfusion of these surfaces is enhanced by ‘anticipatory’ breathing tachycardia during surfacing [ 53 ]. Cutaneous gas exchange with seawater provides approximately a third of the oxygen requirements of sea snakes, and a significant portion of their CO 2 and N 2 loss [ 16 , 17 , 19 , 54 ].…”

Field Physiology: Studying Organismal Function in the Natural Environment

“…The dive response, a suite of physiological changes including a reduced heart rate, allows these animals to make lengthy dives. Studies of aquatic mammals and birds have demonstrated that the diving bradycardia is graded in wild animals at sea (128,131,164,192,201,361), whereas in captive settings, forced submersion experiments elicited extreme responses (268). In red deer, telemetered heart rate and body temperature measurements revealed nocturnal hypometabolism, identifying a strategy for how large ungulates deal with cold winter weather and the associated reduced energy content of food (12).…”

Heart rate reduction during voluntary deep diving in free-ranging loggerhead sea turtles

“…The present results on the flipper stroke rate differed from those of previous studies which indicated that heart rate increased upon the onset of underwater exercise in free-ranging sea snakes ( Heatwole et al, 1979 ) and captive experiments on sea turtles ( Williams et al, 2019 ; Okuyama et al, 2020 ). In sea turtles, heart rate is thought to elevate upon the onset of underwater exercise and increase linearly with exercise ( Okuyama et al, 2020 ) because their major oxygen stores are their lungs ( Lutz and Bentley, 1985 ) and they need to transport oxygen to muscles from their lungs.…”

“…However, specifically in deep dives under natural conditions, the variation of heart rates in free-ranging aquatic reptiles has not been examined. Although field studies on aquatic reptiles have shown a slight reduction in heart rate during diving, these studies were conducted on species that inhabit shallow water, such as freshwater crocodiles ( Seebacher et al, 2005 ), American alligators ( Smith et al, 1974 ) and sea snakes ( Heatwole et al, 1979 ), or on leatherback sea turtles during the interesting interval during which they dived to relatively shallower levels than the levels to which they dive normally during foraging periods ( Southwood et al, 1999 ). Among marine reptiles, sea turtles have outstanding diving abilities.…”

New chromosome-scale genomes provide insights into marine adaptations of sea snakes (Hydrophis: Elapidae)

“…Selection on these genes might contribute to various aspects of the bimodal respiration of sea snakes. The respiratory tissues of the trachea and right lung extend almost the length of the sea snake body and the perfusion of these surfaces is enhanced by ‘anticipatory’ breathing tachycardia during surfacing [ 53 ]. Cutaneous gas exchange with seawater provides approximately a third of the oxygen requirements of sea snakes, and a significant portion of their CO 2 and N 2 loss [ 16 , 17 , 19 , 54 ].…”

Field Physiology: Studying Organismal Function in the Natural Environment

“…The dive response, a suite of physiological changes including a reduced heart rate, allows these animals to make lengthy dives. Studies of aquatic mammals and birds have demonstrated that the diving bradycardia is graded in wild animals at sea (128,131,164,192,201,361), whereas in captive settings, forced submersion experiments elicited extreme responses (268). In red deer, telemetered heart rate and body temperature measurements revealed nocturnal hypometabolism, identifying a strategy for how large ungulates deal with cold winter weather and the associated reduced energy content of food (12).…”

Heart rate reduction during voluntary deep diving in free-ranging loggerhead sea turtles

“…The present results on the flipper stroke rate differed from those of previous studies which indicated that heart rate increased upon the onset of underwater exercise in free-ranging sea snakes ( Heatwole et al, 1979 ) and captive experiments on sea turtles ( Williams et al, 2019 ; Okuyama et al, 2020 ). In sea turtles, heart rate is thought to elevate upon the onset of underwater exercise and increase linearly with exercise ( Okuyama et al, 2020 ) because their major oxygen stores are their lungs ( Lutz and Bentley, 1985 ) and they need to transport oxygen to muscles from their lungs.…”

“…However, specifically in deep dives under natural conditions, the variation of heart rates in free-ranging aquatic reptiles has not been examined. Although field studies on aquatic reptiles have shown a slight reduction in heart rate during diving, these studies were conducted on species that inhabit shallow water, such as freshwater crocodiles ( Seebacher et al, 2005 ), American alligators ( Smith et al, 1974 ) and sea snakes ( Heatwole et al, 1979 ), or on leatherback sea turtles during the interesting interval during which they dived to relatively shallower levels than the levels to which they dive normally during foraging periods ( Southwood et al, 1999 ). Among marine reptiles, sea turtles have outstanding diving abilities.…”

New chromosome-scale genomes provide insights into marine adaptations of sea snakes (Hydrophis: Elapidae)

“…Selection on these genes might contribute to various aspects of the bimodal respiration of sea snakes. The respiratory tissues of the trachea and right lung extend almost the length of the sea snake body and the perfusion of these surfaces is enhanced by ‘anticipatory’ breathing tachycardia during surfacing [ 53 ]. Cutaneous gas exchange with seawater provides approximately a third of the oxygen requirements of sea snakes, and a significant portion of their CO 2 and N 2 loss [ 16 , 17 , 19 , 54 ].…”

Field Physiology: Studying Organismal Function in the Natural Environment

“…The dive response, a suite of physiological changes including a reduced heart rate, allows these animals to make lengthy dives. Studies of aquatic mammals and birds have demonstrated that the diving bradycardia is graded in wild animals at sea (128,131,164,192,201,361), whereas in captive settings, forced submersion experiments elicited extreme responses (268). In red deer, telemetered heart rate and body temperature measurements revealed nocturnal hypometabolism, identifying a strategy for how large ungulates deal with cold winter weather and the associated reduced energy content of food (12).…”