Heart rate and behaviour of fur seals: implications for measurement of field energetics

• Main Authors: Boyd, I. L., Bevan, R. M., Woakes, A. J., Butler, P. J.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: American Physiological Society 1999
• Subjects: Antarctic; Antarc*; Antarctic Fur Seals
• Online Access: http://nora.nerc.ac.uk/id/eprint/503038/; http://ajpheart.physiology.org/content/276/3/H844

Archival data loggers were used to collect information about depth, swimming speed, and heart rate in 23 free-ranging antarctic fur seals. Deployments averaged 9.6 ± 5.6 days (SD) and totaled 191 days of recording. Heart rate averaged 108.7 ± 17.7 beats/min (SD) but varied from 83 to 145 beats/min among animals. Morphometrics explained most variations in heart rate among animals. These interacted with diving activity and swimming speed to produce a complex relationship between heart rate and activity patterns. Heart rate was also correlated with behavior over time lags of several hours. There was significant (P < 0.05) variation among animals in the degree of diving bradycardia. On average, heart rate declined from 100–130 beats/min before the dive to 70–100 beats/min during submersion. On the basis of the relationship between heart rate and rate of oxygen consumption, the overall metabolic rate was 5.46 ± 1.61 W/kg (SD). Energy expenditure appears to be allocated to different activities within the metabolic scope of individual animals. This highlights the possibility that some activities can be mutually exclusive of one another.