The bat-eared fox: A dietary specialist?

Abstract

a b s t r a c tWe studied the degree of dietary specialisation of bat-eared foxes (Otocyon megalotis) by analysing 177 scats collected on a game ranch in central South Africa. Bat-eared foxes generally are considered to be insectivorous with a distinct specialisation on termites, however, our results indicated a much broader and opportunistic diet. Termites were detected in more than 90% of the scats throughout the year, but they only contributed 12-40% to the ingested biomass across seasons. Instead, fruits, primarily bluebush (Diospyros lycioides), were the most important food category in summer (63% biomass) as well as in autumn (74% biomass). Also, high niche breadth values (B = 5.7-6.9 for frequency of occurrence, B = 1.8-4.1 for biomass data) indicated a rather generalistic feeding behaviour. We also documented numerous cases of opportunistic scavenging on carcasses by bat-eared foxes. The difference with earlier dietary studies of bat-eared foxes might be attributable to geographical and ecological variations among sites and also partly to methodological differences. Concerning the latter, no previous studies considered biomass calculations but instead most assessed the frequency of occurrence of prey items, which likely overestimated the importance of small prey such as termites.

Nest survival in year‐round breeding tropical red‐capped larks Calandrella cinerea increases with higher nest abundance but decreases with higher invertebrate availability and rainfall

“…A pattern similar to ours was reported for ground-nesting birds whose main predator were striped skunks Mephitis mephitis that primarily target invertebrates (Vickery et al 1992). Indeed, the primary food of bat-eared foxes and lesser kestrels, the main nest predators that we observed, are invertebrates, although their diet also includes other opportunistic prey, such as birds and eggs (Nel 1978, Anderson et al 1999, Stuart et al 2003, Klare et al 2011. Nest predation by incidental predators can be the major cause of nest failure and significantly decrease daily nest survival rates (Vickery et al 1992, Yanes and Suarez 1996, Martínez-Padilla and Fargallo 2008).…”

Estimating consumable biomass from body length and order in insects and spiders

“…Even in vertebrates, chitinous exoskeletons are not broken down, which is why diet studies based on scat analysis are able to identify insect prey to order, e.g. in bats (Rajemison and Goodman, ; Klare et al ., ) and lizards (Perez‐Cerembranos et al ., ).…”

Monogamy: Cause, Consequence, or Corollary of Success in Wild Canids?

“…Species feeding on medium-sized prey can carry prey to the den, allowing both parents to provision young once they are old enough to be left alone at the den (e.g., red fox, Macdonald, 1977;arctic fox, Cameron et al, 2011), but for largely insectivorous canids, this is unfeasible. In largely termitivorous bat-eared fox (Klare et al, 2011), nursing mothers must spend >85% of the night foraging (Wright, 2003), leaving males primarily responsible for guarding, huddling and grooming cubs (Lamprecht, 1979;Malcolm, 1986;Maas, 1993;Maas and Macdonald, 2004;Wright, 2006). As bat-eared fox cubs begin foraging, the male accompanies them (Wright, 2006), acting as both protector and teacher, indicating patches of food to the cubs and occasionally pre-chewing larger beetles (Maas and Macdonald, 2004).…”

“…Their diets range from the almost exclusively insectivorous (e.g., bat-eared fox [Otocyon megalotis]) to almost exclusively carnivorous (e.g., African wild dog [Lycaon pictus], bush dog [Speothos venaticus], Ethiopian wolf [Canis simensis], Marino et al, 2010), with a full spectrum of omnivory between (e.g., red fox [Vulpes vulpes], golden jackal [C. aureus], African golden wolf [C. lupaster]). Such extremes in diets are reflected in their dentition, because while most canids have 42 teeth well-suited for generalist diets (e.g., carnassials for shearing flesh and molars for omnivory), bat-eared foxes have up to 50 less-specialized teeth (the most of any land mammal) for extreme insectivory (Klare et al, 2011), whereas the dholes, bush dogs, and African wild dogs have reduced or absent molars and enhanced carnassials for hypercarnivory (Van Valkenburgh, 1991). Canids are found in nearly all terrestrial habitats, including such extremes as Arctic tundra (Arctic fox [Vulpes lagopus]), desert (fennec fox), tropical forest (dhole [Cuon alpinus]), high-altitude environments (e.g., Ethiopian wolf, Marino, 2003; Himalayan wolf [C. [lupus] himalayensis], Werhahn et al, 2017Werhahn et al, , 2018 and human cities (e.g., coyote [C. latrans]).…”