Living in a seasonal world: 15th international hibernation symposium
A brief history of the 15 times the international hibernation community has come together is warranted. The first meeting was held May 13–15, 1959 at the Massachusetts Institute of Technology Endicott House (see Table 1). The 26 presented papers in that first meeting focused greatly on the physiology of hibernation and has set the tone for the ensuing meetings. One of the highlights of the meeting and subsequent symposium volume were the candid discussions (Lyman and Dawe 1960). Members of the hibernation community shared insight after each presentation and discussed the future directions of the field. Some of this discussion is seemingly humorous in retrospective. In a discussion as to the ‘validity of the term, hibernation’, one participant debated the meaning of ‘validity’—perhaps highlighting the historical difficulty, the field has had with nomenclature that suitably describes the extraordinary diversity of torpor use. The community was trying to separate out hypothermia from hibernation—a problem that we grappled with even in the 2016 meeting. Indeed, many of the topics pursued in the first meeting are still relevant 58 years later. We know much more than we did then, but we still struggle with the basic questions as to why do animals hibernate or why do almost all hibernators experience periodic euthermic arousals during the winter. Every 3–6 years, meetings were held. Proceedings were published a year or two after the meeting. The impact of these meetings was tremendous even early on. As far as we can tell, the first suggestion that brown adipose tissue was thermogenic came from Robert E. Smith in the 2nd symposium in 1962. Smith discussed how no satisfactory physiological role had yet been assigned to brown adipose tissue and then presented data that supported a role for thermogenesis and homeothermy. The ideas presented at the meeting in 1962 led to the landmark paper in Science demonstrating the role of brown adipose tissue in thermogenesis This special issue of the Journal of Comparative Physiology B is dedicated to papers arising from the 15th International Hibernation Symposium held in Las Vegas, NV, USA from July 31–August 4th, 2016. These symposia occur every 4 years and bring together virtually all of the world’s experts on mammalian hibernation. The 2016 program was primarily focused on mammalian hibernation with presentations on topics such as the evolution or plasticity of torpor use, how hibernation impacts on physiological systems such as the immune system, muscles, or bones, the molecular underpinnings of hibernation, and biomedical implications and prospects from hibernation. Mammals such as ground squirrels, bats, tenrecs, bears, echidnas, dormice, and lemurs were discussed. However, there was also discussion about birds, fish, lizards, and snakes and even gut microbial communities. Approaches towards solving problems spanned from ecological to physiological to biochemical and molecular strategies. Importantly, the program extended beyond hibernation and included the basic science of thermoregulation, hypoxia tolerance, brown adipose tissue function, and cold adaptation. Perhaps, most extraordinary about these meetings is the lack of formal rules or programming guidelines. The meeting was organized based on contributions and truly reflects the diversity of evolving research paradigms. Posters were encouraged to reflect the latest projects and allowed for insightful discussion.