Paleoecological reconstruction of Late Pleistocene deer from the Ryukyu Islands, Japan: Combined evidence of mesowear and stable isotope analyses

Variation and process of life history evolution in insular dwarfism as revealed by a natural experiment

“…2B). The deer mortality data of the Kinkazan Island population was additionally included as it provided the mortality pattern free from hunting pressure [38], that is also the case for C. astylodon and the Ryukyu muntjac inhabiting on Pleistocene Okinawa Island without human and other predators [38, 39]. As the age estimation of C. astylodon was based on the lower third molar height, we confined the survivorship curves to juvenile and onwards for C. astylodon and the sika deer.…”

“…As with Kerama deer, it is possible that phenotypic plasticity partially influenced the growth trajectories of them. We do not currently have any reliable sources of information on the nutritional status of fossil deer, except for their dietary habits [39, 46]. However, reports of healed bone fractures on a number of leg bones from a museum collection of fossil insular deer of Okinawa Island [47] implies that these deer survived long enough to recover from serious leg injuries, refuting the possibility that fossil Okinawa deer were malnourished and their body growth was suppressed due to a lack of resources.…”

“…As with the Kerama deer, it was proposed that phenotypic plasticity partially influenced their growth trajectories. However, we do not currently have reliable sources of information on the nutritional status of the fossil deer, except for their dietary habits [61, 64]. Nevertheless, reports of healed bone fractures on several leg bones from a museum collection of fossil insular deer species on the Okinawa Island have been recorded, which implies that this deer survived long enough to recover from serious leg injuries.…”

“…Additionally, we obtained mortality data of sika deer from Kinkazan Island from the published literature (N = 264) [60]. The Kinkazan population is protected for religious reasons and thus free from hunting pressure, which was also the case for C. astylodon and the Ryukyu muntjac inhabiting the Pleistocene Okinawa Island without human and other predators [60, 61]. The age data for extant Reeves’s muntjac from England was obtained from a published reference (N = 84)[62].…”