Heart rate values for beaver, mink and muskrat

Area of Science:

• Comparative physiology
• Aquatic mammal behavior
• Cardiovascular responses in wildlife

Background:

• Understanding the physiological adaptations of semi-aquatic mammals is crucial for ecological studies.
• Heart rate variability provides insights into metabolic rates and stress responses in animals.

Purpose of the Study:

• To investigate and compare the heart rate responses of beaver, mink, and muskrat during different activities.
• To analyze diving bradycardia and other behavioral heart rate patterns in these species.

Main Methods:

• Implanted electrocardiogram (ECG) transmitters were utilized to record heart rates in beaver (Castor canadensis), mink (Mustela vison), and muskrat (Ondatra zibethicus).
• Physiological data were collected under controlled, free-ranging laboratory conditions within an aquatic environment.

Main Results:

• All three species exhibited significant bradycardia (decreased heart rate) during diving.
• Mink heart rates returned to pre-dive levels after dives exceeding 30 seconds.
• Non-diving heart rates were significantly higher (P < 0.05), averaging 120/min (beaver), 265/min (mink), and 240/min (muskrat).

Conclusions:

• Diving elicits a conserved bradycardia response across these semi-aquatic mammals.
• Mink display unique heart rate recovery patterns potentially linked to their fusiform body shape and energetic demands.
• Observed mink heart rates suggest deviations from standard energetic equations, highlighting species-specific physiological traits.