Myrmecophagy of Japanese black bears in the grasslands of the Ashio area, Nikko National Park, Japan

Yamazaki, Koji; Kozakai, Chinatsu; Koike, Shinsuke; Morimoto, Hideto; Goto, Yusuke; Furubayashi, Kengo

doi:10.2192/ursus-d-10-00012.1

Cited by 61 publications

(16 citation statements)

References 15 publications

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“…Firstly, philopatric females have the knowledge of the distribution of food resources in their home site. Bears in our study area mainly consumed herbs, young leaves of trees, and deer carcasses in spring and ants in patches of grassland in summer (Yamazaki et al 2012;Fujiwara et al 2013;Koike et al 2016). The distribution of food did not differ largely among years.…”

Section: Discussionmentioning

confidence: 85%

“…This high foraging efficiency may increase reproductive success, as has been observed in American black bears (Kolenosky 1990). However, because the potential energy gain from eating ants was insufficient to meet their basal and field metabolic needs (Yamazaki et al 2012), the foraging efficiency of eating only ants did not cause female philopatry in our study area.…”

Section: Discussionmentioning

confidence: 86%

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Influence of Food Availability on Matrilineal Site Fidelity of Female Asian Black Bears

et al. 2017

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 86%

Influence of Food Availability on Matrilineal Site Fidelity of Female Asian Black Bears

et al. 2017

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“…, Yamazaki et al. ), we determined the dry weight per single unit (e.g., one fruit, one leaf) and the gross energy content of major food items identified from the fecal analysis. Gross energy content for carbohydrates, crude protein, and fat were estimated at 4.2, 4.8, and 9.5 kcal/g dry weight, respectively, based on values provided by the Association of Official Analytical Chemists (Williams ).…”

Section: Methodsmentioning

confidence: 99%

“…We drew on the existing literature (Yamazaki et al. , Fujiwara et al. ) and calculated this as average weight of ants per stone (89.9 mg/stone) × stones/min.…”

Section: Methodsmentioning

confidence: 99%

“…Thus, Asian black bears may not even satisfy their base metabolism, with ants as the main source of food in the summer (Yamazaki et al. ). In addition, although bears hibernate during winter, a certain amount of energy is still necessary for survival, and fat accumulated prior to hibernation is the energy source consumed during hibernation (Nelson et al.…”

Section: Introductionmentioning

confidence: 99%

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Estimating the seasonal energy balance in Asian black bears and associated factors

et al. 2019

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Energy balance (i.e., energy intake minus energy expenditure) is an essential factor when evaluating an animal's nutritional state. We aimed to identify periods of the year that are most important for Asian black bears (Ursus thibetanus) in terms of energy balance. We estimated bears’ daily energy balance by estimating energy intake based on the energy content (kcal/g) of major food items, their average ingestion rate (g/min), and daily feeding time (min) and by estimating energy expenditure using an equation for the costs of resting, traveling, and feeding based on behavioral data of 34 bears fitted with GPS collars in central Japan. Because food habits of bears change seasonally, we estimated daily energy balance for each month. And, because bears change their feeding behavior depending on the availability of hard mast, we made separate estimations for years of good and poor mast conditions during autumn. We identified major food items from fecal analysis and calculated the gross energy content per unit for each item. Based on direct observation of bears feeding over 10 yr, we measured ingestion rates of the major food items; Quercus crispula acorns on the tree had the highest ingestion rate, whereas the values of other items did not show notable characteristics. The variability of energy expenditure rose moderately in good mast years, except for males. On the other hand, there was a bimodal pattern of energy intake and energy balance, declining from May to July, rising again from August to October, and declining in November. The peak of energy intake and energy balance was larger in good mast years than in poor mast years only for females, whereas the cumulative energy balance in good mast years was larger than in poor mast years for both sexes. After poor mast years, the cumulative energy balance of males becomes negative in February, during hibernation, and did not exceed zero until August, even if they could start feeding in May. Thus, further longitudinal studies that examine cumulative energy balance, rather than energy balance alone, are necessary to clarify the seasonal change in the nutritional state of Asian black bears.

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Temporal and individual variation in the feeding habits of Asiatic black bears (Ursus thibetanus)

Mori,

Izumiyama

2024

Ecology and Evolution

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Foraging plays a vital role in the survival of wildlife, and shifts in food availability can impact species fitness and survival. Ursids are known to consume a wide variety of foods and are known to be opportunistic omnivores. Consequently, seasonal shifts in diet, which correspond to temporal and spatial shifts in the availability of food resources, have long captivated researchers studying the foraging behavior of Ursidae. Nevertheless, comprehensive dietary studies encompassing both the population and individual levels remain scarce. In this study, we investigated the dietary patterns of Asiatic black bears (Ursus thibetanus) at both the population and individual levels, using data collected through GPS collars and field surveys of individual bear scat samples in Nagano Prefecture, Japan, from 2016 to 2020. From early April to late June, bears mainly foraged on green vegetation. During this period, male and large‐bodied female bears showed a strong preference for green vegetation. Small‐bodied female bears also ate mostly green vegetation but tended to consume more fruit than other bears towards the end of this period. From June to October, bears' diets included a substantial amount of fruit, with notable peaks in fruit consumption in late June and early September. During the summer months, female bears often incorporated social insects into their diet compared to the population‐level trend. In mid‐September, the consumption of seeds from the Fagaceae family surged, becoming the primary dietary component during this period. This trend was consistently observed across the population. These findings underscore the importance conducting in‐depth dietary analyses that take into account individual characteristics such as sex, age, and body weight.

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Myrmecophagy of Japanese black bears in the grasslands of the Ashio area, Nikko National Park, Japan

Cited by 61 publications

References 15 publications

Influence of Food Availability on Matrilineal Site Fidelity of Female Asian Black Bears

Influence of Food Availability on Matrilineal Site Fidelity of Female Asian Black Bears

Estimating the seasonal energy balance in Asian black bears and associated factors

Temporal and individual variation in the feeding habits of Asiatic black bears (Ursus thibetanus)

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