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Giant pandas eat bamboo, almost exclusively (Sheldon 1937; Davis 1964; Schaller et al. 1985; Nie, Zhang, et al. 2015; Nie, Speakman, et al. 2015) Individuals typically eat several species of bamboo in their habitat, each season Over 98% of diet is bamboo (Schaller et al. 1985; Hu and Wei 2004; Garshelis 2009b; Swaisgood et al. 2020) Estimate reflects early studies from managed care settings; diet of wild populations may be slightly more flexible (Long et al. 2004) Known to eat more than 40 bamboo species (Swaisgood et al. 2020; Dingzhen Liu, personal communication, 2025, citing Ren 2006 and State Forestry Administration 2015) Usually, several bamboo species found in each elevation band (of each mountain range pandas occur in) (Swaisgood et al. 2020) Hu and Wei (2004) report which bamboo species pandas consume in different mountain ranges Comparison to other bears Diets of other bear species also high in plants, except for (Iversen et al. 2013; Rinker et al. 2019) Distant ancestors of today’s giant pandas had a more diverse and complex diet (see Han et al. 2019) Also see Other diet items (rarely eaten)Plants other than bamboo Eat from herbs, vines, shrubs, and trees (Chu and Long 1983, cited by Schaller et al. 1985; Schaller et al. 1985) Consume leaves, stems, roots, fruits, and barks in very small amounts (Morris and Morris 1966; Chorn and Hoffman 1978 citing Giant Panda Expedition 1974; Schaller et al. 1985; Hu and Wei 2004; Garshelis 2009b) Meat and carrion (dead animals) Not well documented but appear to opportunistically scavenge on small animals, such as rodents and small dead hooved animals (deer, boar) (Brambell 1976; Hu and Wei 2004; Garshelis 2009b) Eat animal bones and hides (eg, of wild boar) (Long et al. 2004) Eating carrion and bones most commonly observed in pregnant or lactating females, according to Long et al. (2004) May have nutritional benefits (eg, additional vitamins) but needs more research (Long et al. 2004) Sand or soil Observed, but rare (see Long et al. 2004) Food sources from humans Crops (Hu and Wei 2004; Garshelis 2009b) If bamboo is scarce, may eat crops, including pumpkin, beans, and wheat [reported from Minshan range] (Hu and Wei 2004) Domestic animal feeds, such as pig food (Hu and Wei 2004) Pig bones thrown away by humans (Long et al. 2004) Some pandas seek out crops or trash (food waste), even when bamboo is available (Garshelis 2009b)
Feeding
Feeding behavior Bamboo handling Select bamboo stems (culms) of diameters that are easy to hold and chew (Garshelis 2009b) Usually sit or recline on haunches, leaving feet free to hold/manipulate bamboo (Davis 1964; Schaller et al. 1985; Garshelis 2009b) Grasp bamboo leaves or stem with front feet, between palm and thumb-like digit (e.g., Jones 1939; Endo et al. 1999) Strong teeth strip off tough outer layer of bamboo stem and back molars grind down (Chorn and Hoffman 1978) Grasp bamboo stalk with teeth and insert into corner of mouth (Schaller et al. 1985; Garshelis 2009b) Then repeatedly bite off sections, about 2 to 5 cm long Chew little (Garshelis 2009b) Also see Physical Characteristics Handle and process food quickly (break, crush, chew, swallow) (Schaller et al. 1985) Eating a lot of food quickly compensates for diet that is not energy-dense or nutritionally dense (Schaller et al. 1985; Nie, Speakman, et al. 2015; Swaisgood et al. 2020) An average-sized panda (weighing 100 kg, or about 220 lb) might eat 12 to 15 kg (26 to 33 lb) of bamboo leaves and stems, or 23 to 38 kg (50 to 84 lb) of bamboo shoots per day (Schaller et al. 1985; Pan and Lü 1993; Swaisgood et al. 2020) As a measure of dry matter, this is about 6% of a panda’s body weight (Dierenfeld et al. 1982) Activity patterns Spend more than half of their time foraging (Dierenfeld et al. 1982; Swaisgood, Wang, et al. 2016) Active for roughly 14 hours per day (sometimes longer); spend most of this time foraging (Schaller et al. 1985; Pan and Lü 1993; Zhang et al. 2015; Swaisgood et al. 2020) Also see Changes seasonally—spend more time foraging in late winter and early spring, when high-quality bamboo is scarcer (Y. Li et al. 2017) Optimizing nutritionForaging strategy changes throughout the year, as the nutritional quality of bamboo changes (Schaller et al. 1985; Li et al. 2017) Pandas select the most nutritious bamboo during the optimal period of plant growth (eg, Hu and Wei 2004; Nie, Zhang, et al. 2015; Swaisgood et al. 2020) Tend to focus foraging activity where denser bamboo, taller bamboo, and younger bamboo stems and leaves, which have more nutrients (Nie, Zhang, et al. 2015; Kang et al. 2019; Yang et al. 2024) “Forage most intensively at the most nutritious, protein-rich, cellulose-poor patches” (Swaisgood et al. 2020) Bamboo selection Eat different species of bamboo growing at different elevations, during different seasons, to improve their nutrition (Schaller et al. 1985; Hu and Wei 2004; Nie, Zhang, et al. 2015; Nie et al. 2019; Yang et al. 2024) Seek out protein, amino acids, certain minerals, etc. Might select bamboo with certain chemical compounds, such as high levels of flavonoids, an antioxidant (eg, Wang et al. 2020; Yang et al. 2024) More research needed; see Yang et al. (2024) for more discussion Bamboo parts Pandas switch between eating shoots and leaves, and stems and branches (Garshelis 2009b; Nie, Zhang, et al. 2015; Y. Li et al. 2017; Nie et al. 2019; Robbins et al. 2022) Most energy gained from carbohydrates and protein (Nie et al. 2019; Robbins et al. 2022) See “Seasonal changes in feeding,” below Finding foodOften select foraging patches close together to reduce exertion and the need to move longer distances (eg, Schaller et al. 1985; W. Wei et al. 2015) Prefer foraging on gentle slopes and close to water (W. Wei et al. 2015) Return to same foraging areas, year after year (Swaisgood et al. 2016; M. Wang et al. 2023) Likely have a well-developed spatial memory (Swaisgood et al. 2016; M. Wang et al. 2023) Seasonal changes in feedingFood quality Amount and quality of bamboo available to pandas changes seasonally (Swaisgood et al. 2016; Y. Li et al. 2017) Pandas migrate, in part, to find higher-quality food and improve their nutrition (Nie, Zhang, et al. 2015; M. Wang et al. 2023) Also see Hardest to find food at end of winter, just before the energy-demanding mating period begins (Swaisgood et al. 2020) Parts of bamboo Eat different parts at different times of year, selecting the most nutritious parts (Schaller et al. 1985; Christian et al. 2015; Nie, Zhang, et al. 2015; Swaisgood, Wang, et al. 2016) Also see “Optimizing nutrition,” above Prefer shoots, when seasonally available in spring (Swaisgood, Wang, et al. 2016) (Nie et al. 2019) Coincides with mating period (Nie, Zhang, et al. 2015) Bamboo shoots particularly important to pandas at end of winter, after an extended period when less nutrient-dense bamboo is available (Schaller et al. 1985; Pan et al. 2014; Christian et al. 2015; Y. Li et al. 2017; Swaisgood et al. 2020) Mainly eat leaves in summer and fall (Nie, Zhang, et al. 2015) (Swaisgood, Wang, et al. 2016) Coincides with birthing period (Nie, Zhang, et al. 2015) Stems and older leaves eaten more commonly during winter, when bamboo growth slows (Swaisgood, Wang, et al. 2016) DrinkingFrequency of water consumption Not well studied Yong (1981) (cited by Schaller et al. 1985) concluded that giant pandas drink at least once per day; based on limited evidence Water sources Streams, pools, and puddles (Schaller et al. 1985) Water lost through feces; pandas must replace water through drinking or bamboo with a high water content (during rainy season) (Schaller et al. 1985) Digestion and scatGut anatomy Stomach Simple in structure (see Loeffler et al. 2006) “Thick-walled and muscular, almost gizzard-like” (Chorn and Hoffman 1978) Intestines Remarkably short for an herbivore (Loeffler et al. 2006) Only about 4 to 5 times their body length (Chorn and Hoffman 1978; Loeffler et al. 2006) Length more similar to that of meat-eating carnivores than herbivores (Loeffler et al. 2006) Little differentiation (separation) between small and large intestines (Loeffler et al. 2006) Digestion Digestive tract adapted for extracting bamboo cell contents quickly (Davis 1976; Schaller et al. 1985) Do not digest plant cell fibers or cell walls, as other herbivores do (Loeffler et al. 2006; Li et al. 2010) Difficult for giant pandas to digest cellulose (Dierenfeld et al. 1982; Zhu, Wu, et al. 2011; Wei et al. 2012) Physical adaptations, plus gut microbes, allow pandas to live on a mostly bamboo diet (eg, Zhu et al. 2011; Xue et al. 2015) Gut passage time Food not retained in digestive tract for long (Schaller et al. 1985) Takes food about 5 to 13 hours to pass through (Dierenfeld et al. 1982; Schaller et al. 1985) Scat Poop about 50 times per day (Swaisgood et al. 2020) May contain fragments of bamboo that are very similar in size (Garshelis 2009b) (责任编辑:) |
