Postanesthetic monitoring of core body temperature using telemetry in North American river otters (Lutra canadensis).

Remote thermal telemetry was performed on North American river otters (Lutra canadensis) during the 1995 North Carolina Wildlife Resources Commission Otter Restoration Project. Otters were anesthetized with either ketamine-midazolam (n = 11) or tiletamine-zolazepam (n = 9) combinations. Based upon initial rectal temperatures, mild to moderate hyperthermia (39.4-40.5 degrees C) developed in five otters given ketamine-midazolam and three otters given tiletamine-zolazepam. Following anesthetic induction, each otter received an ingestible temperature transmitter. Dependent upon gastrointestinal transit time and transmitter battery life, core body temperature was monitored for up to 13.75 hr postanesthesia. Thermal telemetry revealed a gradual decline in core temperature in all otters after anesthetic recovery (30-60 min). Median core temperature stabilized subsequently within 0.3 degrees C of resting temperature (38.4 degrees C) 1.75 hr after initial injection in otters given tiletamine-zolazepam and 2.75 hr in otters given ketamine-midazolam. Minor fluctuations in body temperature (less than 1 degree C) occurred in most otters from 6 to 13.75 hr and were attributed to variations in physical activity.