In early summer, large ungulates typically show a single seasonal peak for heart rate. A recent study performed at the University of Veterinary Medicine in Vienna, Austria, demonstrates that this does not hold true for female wild boars (Sus scrofa), using heart rate as a proxy for energy expenditure.

Heart Rate, temperature and activity measured with bio-loggers
To learn more about how wild boar respond to seasonal environments heart rate, core body temperature, subcutaneous temperature, and activity was measured in 10 free-ranging female wild boars.

The bio-loggers used in this study included Star-Oddi’s DST centi-HRT, leadless heart rate and temperature loggers.

Seasonal heart rate likely driven by reproductive cost
Unlike other large ungulates, the wild boar in the study demonstrated peak heart rates in early April. The lowest monthly averages were measured over the summer period followed by a second peak in autumn or early winter.

The seasonal heart rate rhythm measured in this study indicates that it is caused by the cost of reproduction rather than just thermoregulatory costs.

The paper was published in Nature's Scientific Reports and can be accessed in full here.