University of Minnesota, Department of Surgery, Minneapolis, 55455, USA.
Minnesota Department of Natural Resources, Grand Rapids, 55744, USA.
Sci Rep. 2017 Jan 17;7:40732. doi: 10.1038/srep40732.
Physiological monitoring of free-ranging wild animals is providing new insights into their adaptations to a changing environment. American black bears (Ursus americanus) are highly adaptable mammals, spending up to half the year hibernating, and the remainder of the year attempting to gain weight on a landscape with foods that vary seasonally and year to year. We recorded heart rate (HR) and corresponding activity of an adult female black bear over the course of six years, using an implanted monitor. Despite yearly differences in food, and an every-other year reproductive cycle, this bear exhibited remarkable consistency in HR and activity. HR increased for 12 weeks in spring, from minimal hibernation levels (mean 20-25 beats/minute [bpm]; min 10 bpm) to summer active levels (July daytime: mean 95 bpm). Timing was delayed following one cold winter. In August the bear switched from primarily diurnal to nocturnal, coincident with the availability of baits set by legal hunters. Activity in autumn was higher when the bear was with cubs. Birthing of cubs in January was identified by a transient increase in HR and activity. Long-term physiological and behavioral monitoring is valuable for understanding adaptations of free-ranging animals to climate change, food availability, and human-related stressors.
对野生动物的生理监测为它们对环境变化的适应提供了新的见解。美洲黑熊（Ursus americanus）是一种高度适应性的哺乳动物，它们会冬眠半年，其余时间则试图在食物季节性和年度变化的环境中增加体重。我们使用植入式监测器记录了一只成年雌性黑熊在六年中的心率（HR）和相应的活动。尽管食物每年都有差异，而且每两年有一次繁殖周期，但这只熊的 HR 和活动表现出了显著的一致性。在春季，心率会升高 12 周，从最低冬眠水平（平均 20-25 次/分钟[bpm]；最低 10 bpm）升高到夏季活跃水平（7 月白天：平均 95 bpm）。由于一个寒冷的冬天，时间有所延迟。8 月，熊从主要的昼行性转变为夜行性，与合法猎人设置的诱饵供应时间一致。当熊与幼崽在一起时，秋季的活动量更高。HR 和活动的短暂增加表明熊在 1 月分娩了幼崽。长期的生理和行为监测对于了解野生动物对气候变化、食物供应和与人类相关的压力源的适应能力非常有价值。
