My co-authors and I are pleased to announce our new open access publication in *PeerJ* about humpback whale nursing behavior on the feeding grounds: Tackaberry JE, Cade DE, Goldbogen JA, Wiley DN, Friedlaender AS, Stimpert AK. 2020. From a calf’s perspective: humpback whale nursing behavior on two US feeding grounds. *PeerJ* 8:e8538 https://doi.org/10.7717/peerj.8538 Link to full text with videos: https://peerj.com/articles/8538 Abstract: Nursing influences growth rate and overall health of mammals; however, the behavior is difficult to study in wild cetaceans because it occurs below the surface and can thus be misidentified from surface observations. Nursing has been observed in humpback whales on the breeding and calving grounds, but the behavior remains unstudied on the feeding grounds. We instrumented three dependent calves (four total deployments) with combined video and 3D-accelerometer data loggers (CATS) on two United States feeding grounds to document nursing events. Two associated mothers were also tagged to determine if behavior diagnostic of nursing was evident in the mother’s movement. Animal-borne video was manually analyzed and the average duration of successful nursing events was 23 s (±7 sd, n = 11). Nursing occurred at depths between 4.1–64.4 m (along the seafloor) and in close temporal proximity to foraging events by the mothers, but could not be predicted solely by relative positions of mother and calf. When combining all calf deployments, successful nursing was documented eleven times; totaling only 0.3% of 21.0 hours of video. During nursing events, calves had higher overall dynamic body acceleration (ODBA) and increased fluke-stroke rate (FSR) compared to non-nursing segments (Mixed effect models, ODBA: F1,107 = 13.57756, p = 0.0004, FSR: F1,107 = 32.31018, p < 0.0001). In contrast, mothers had lower ODBA and reduced FSR during nursing events compared to non-nursing segments. These data provide the first characterization of accelerometer data of humpback whale nursing confirmed by animal-borne video tags and the first analysis of nursing events on feeding grounds. This is an important step in understanding the energetic consequences of lactation while foraging. -- Jennifer Tackaberry Vertebrate Ecology Lab <https://www.mlml.calstate.edu/birdmam/> - Moss Landing Marine Laboratories Research Biologist - Cascadia Research Collective <http://www.cascadiaresearch.org> Adjunct Scientist - Center for Coastal Studies <http://coastalstudies.org>