phaidra.vetmeduni.ac.at o:5329 DOI 10.1038/s41598-021-97825-z Atypical for northern ungulates, energy metabolism is lowest during summer in female wild boars (Sus scrofa) Typically, large ungulates show a single seasonal peak of heart rate, a proxy of energy expenditure, in early summer. Different to other large ungulates, wild boar females had peak heart rates early in the year (at ~ April, 1), which likely indicates high costs of reproduction. This peak was followed by a trough over summer and a secondary summit in autumn/early winter, which coincided with the mast seeding of oak trees and the mating season. Wild boars counteracted the effects of cold temperatures by decreasing subcutaneous body temperature by peripheral vasoconstriction. They also passively gained solar radiation energy by basking in the sun. However, the shape of the seasonal rhythm in HR indicates that it was apparently not primarily caused by thermoregulatory costs but by the costs of reproduction. Wild boar farrow early in the year, visible in high HRs and sudden changes in intraperitoneal body temperature of females. Arguably, a prerequisite for this early reproduction as well as for high energy metabolism over winter is the broad variety of food consumed by this species, i.e., the omnivorous lifestyle. Extremely warm and dry summers, as experienced during the study years (2017, 2018), may increasingly become a bottleneck for food intake of wild boar. eng Heart rate energy metabolism season acclimatization thermoregulation basking 2026-07-14T10:00:17.069Z LOMv1.0 Author BEGIN:VCARD VERSION:3.0 N:Ruf;Thomas; FN:Thomas Ruf X-ORCID:https://orcid.org/0000-0002-9235-7079 END:VCARD BEGIN:VCARD VERSION:3.0 N:Vetter;Sebastian G.; FN:Sebastian G. Vetter X-ORCID:https://orcid.org/0000-0001-5374-5872 END:VCARD BEGIN:VCARD VERSION:3.0 N:Painer;Johanna; FN:Johanna Painer X-ORCID:https://orcid.org/0000-0003-3929-511X END:VCARD BEGIN:VCARD VERSION:3.0 N:Stalder;Gabrielle; FN:Gabrielle Stalder X-ORCID:https://orcid.org/0000-0002-8901-1181 END:VCARD BEGIN:VCARD VERSION:3.0 N:Bieber;Claudia; FN:Claudia Bieber X-ORCID:https://orcid.org/0000-0001-8919-3117 END:VCARD https://w3id.org/kim/hcrt/scheme https://w3id.org/kim/hcrt/text Textdokument Text LOMv1.0 yes https://creativecommons.org/licenses/by/4.0 application/pdf 2473008 https://phaidra.vetmeduni.ac.at/o:5329 https://phaidra.vetmeduni.ac.at/api/object/o:5329/thumbnail LOMv1.0 discipline