Dear all at MARMAM I am very happy to announce that our paper on the ontogeny of echolocation, diving, and communication in sperm whales has just been published in Behavioral Ecology and Sociobiology. Below you can find the abstract and a link to the full text. I am very happy to answer any questions or send out a pdf version of the paper, just contact me at: pernille-t@bios.au.dk. Best Pernille Tønnesen Aarhus University, Denmark First year sperm whale calves echolocate and perform long, deep dives Pernille Tønnesen1, Shane Gero1, Michael Ladegaard1, Mark Johnson2, and Peter T. Madsen1,3 1 Zoophysiology, Department of Bioscience, Aarhus University, Aarhus 8000, Denmark. 2 Sea Mammal Research Unit, University of St. Andrews, St. Andrews KY16 8LB, Scotland, UK. 3 Aarhus Institute of Advanced Studies, Høegh-Guldbergs Gade 6B, DK-8000 Aarhus C, Denmark Abstract Deep diving sperm whales have a complex social structure and the biggest brains on the planet, but very little is known about the ontogeny of their diving, foraging, echolocation, and communication skills. In large brained terrestrial species, social skills develop earlier than locomotor abilities; but this may not be feasible for sperm whales, which require locomotor skills from birth to breathe, swim, and suckle. Here we show the first evidence in any wild toothed whale for the relative development of social and locomotor capabilities. Sound and movement recording tags deployed on three first-year sperm whale calves for a total of 15 hours revealed that these calves rarely produced codas for communication with adult whales, but likely tracked the ample passive acoustic cues emitted by clicking adults. The calves' diving capabilities were well developed (maximum dive depth: 285, 337, and 662 m, maximum dive time: 11, 31, and 44 min) and they all produced clicks in a way that is consistent with echolocation. The calf performing the longest and deepest dives additionally emitted two echolocation buzzes, suggesting that it attempted to forage. Thus, sperm whales calves may supplement their milk diet with food caught independently at depth much earlier than previously believed. Contrary to terrestrial mammals, we propose that the maturation of locomotor, diving, and echolocation skills are favored over investment in developing social communication skills at an early age in sperm whales. Link to full text: https://link.springer.com/article/10.1007/s00265-018-2570-y