Dear MARMAM readers, On behalf of my co-authors, I am pleased to announce the publication of our new paper which has just appeared in American Journal of Physics: "A perfectly inelastic collision: Bulk prey engulfment by baleen whales and dynamical implications for the world's largest cetaceans"; By Potvin J, Cade DE, Werth AJ, Shadwick RE and Goldbogen JA Abstract: The largest animals are the rorquals, a group of whales which rapidly engulf large aggregations of small-bodied animals along with the water in which they are embedded, with the latter subsequently expulsed via filtration through baleen. Represented by species like the blue, fin, and humpback whales, rorquals can exist in a wide range of body lengths (8–30 m) and masses (4000–190,000 kg). When feeding on krill, kinematic data collected by whale-borne biologging sensors suggest that they first oscillate their flukes several times to accelerate towards their prey, followed by a coasting period with mouth agape as the prey-water mixture is engulfed in a process approximating a perfectly inelastic collision. These kinematic data, used along with momentum conservation and time-averages of a whale’s equation of motion, show the largest rorquals as generating significant body forces (10–40 kN) in order to set into forward motion enough engulfed water to at least double overall mass. Interestingly, a scaling analysis of these equations suggests significant reductions in the amount of body force generated per kilogram of body mass at the larger sizes. In other words, and in concert with the allometric growth of the buccal cavity, gigantism would involve smaller fractions of muscle mass to engulf greater volumes of water and prey, thereby imparting a greater efficiency to this unique feeding strategy. Potvin J, Cade DE, Werth AJ, Shadwick RE and Goldbogen JA (2020). "A perfectly inelastic collision: Bulk prey engulfment by baleen whales and dynamical implications for the world's largest cetaceans" American Journal of Physics 88: 851 – 863, 2020; https://doi.org/10.1119/10.0001771 This is an Open Access article: Link to journal: https://aapt.scitation.org/doi/10.1119/10.0001771 Link to PDF: https://aapt.scitation.org/doi/pdf/10.1119/10.0001771 Enjoy! Jean Potvin potvinj@slu.edu "So many ideas, so little time..." Jean Potvin Department of Physics Shannon Hall rm. 111 Saint Louis University 3511 Laclede Ave. St. Louis MO, 63103 314-977-8424 https://sites.google.com/a/slu.edu/jeanpotvin/ https://www.researchgate.net/profile/Jean_Potvin https://twitter.com/LaboPotvin