Unusual observation of an ocelot (Leopardus pardalis) eating an adult Linnaeus’s two-toed sloth
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Unusual observation of an ocelot (Leopardus pardalis) eating an adult Linnaeus’s two-toed sloth (Choloepus didactylus) Miguel Delibes a,∗ , Javier Calzada b , Cuauhtémoc Chávez c , Eloy Revilla a , Beatriz A. Ribeiro d , Denise Prado e , Claudia Keller e , Francisco Palomares a
a b s t r a c t Keywords: Amazonia Felids Prey use Viruá National Park The behaviour of an ocelot (Leopardus pardalis) eating from an adult Linnaeus’ two-toed sloth (Choloepus didactylus) was described. Observation was made at the Viruá National Park of northern Brazil. The sloth had an estimated weight of 7 kg and a portion of its hairs were plucked after the kill. The ocelot began to eat its prey by the braincase. Three days after the finding, only the harder parts of skin and the bones of the extremities of the sloth remained. Field observations of ocelots while eating are very rare and sloths are unusual prey. The ocelot (Leopardus pardalis) is one of the best known neotrop- ical cats, with a distribution ranging from southern Texas to northern Argentina and occupying a large variety of covered habi- tats, from tropical humid forests to marshes and dry scrublands (Murray and Gardner, 1997; Sunquist and Sunquist, 2002). Until recently, it was commonly accepted that the ocelot was specialized on small sized prey, mainly rodents (Emmons, 1987). For example, more than 90% of the ocelot prey in Venezuela weighs less than 1 kg (Sunquist and Sunquist, 2002) and more than 65% of its prey in Peru weighs less than 100 g (Emmons, 1987). Larger prey, however, such as capybaras (Hydrochaeris hydrochaeris), agoutis (Dasyprocta spp.), brocket deer species (Mazama spp.), armadillos (Xenarthra), pecca- ries (Tayassu spp.) and monkeys (Primates), are occasionally taken (Murray and Gardner, 1997; Sunquist and Sunquist, 2002). How- ever, recent evidence suggests that local populations may strongly depend on large prey items. For example, at Caratinga Biological Station, southeast Brazil, ocelots feed mainly on small rodents and birds, but primates, especially the brown howler monkey (Alouatta guariba), were found in 27% of the analyzed faeces (Bianchi and Mendes, 2007). The authors attribute the high frequency of howler monkeys in ocelot diet to the high density of these primates (≥1  ∗ Corresponding author at: Department of Conservation Biology, Estación Biológ- ica de Don˜ ana, CSIC, C Américo Vespucio, s/n, Isla de la Cartuja, 41092 Sevilla, Spain. Tel.: +34 954 466700; fax: +34 954 621125.
E-mail address: mdelibes@ebd.csic.es (M. Delibes). individual per hectare) and their relative vulnerability in the study area. In the same way, on Barro Colorado Island, Panama, Moreno et al. (2006) showed that the ocelot relies mostly on Central American agoutis (Dasyprocta punctata) and sloths (Choloepus hoffmanni and Bradypus variegatus). The authors consider that the ocelot shifted its diet towards larger prey on Barro Colorado as a result of the com- petitive release motivated by the absence of the jaguar (Panthera onca) on the island. Ocelots are rarely sighted in nature (Emmons, 1988) and we do not know of any direct observation of ocelots closely associated to a large prey (most data come from analyses of faeces). Thus, the way they kill and manipulate prey in the wild is unknown. Here we report on a direct observation of an ocelot after presumably capturing and eating an adult Linnaeus’ two-toed sloth (Choloepus didactylus) at the Viruá National Park (northern Brazil). The Viruá National Park (01◦ 29t 12tt N, 61◦ 02t 52tt W, 01◦ 26t 29tt S, 61◦ 00t 08tt E) covers 227,000 ha at the center of the state of Roraima (Brazil), and it is bordered by the Branco river and its tributary Anauá. The vegetation is characterized by a transition between grass- and scrubland (campina), lower-canopy and more open forest (camp- inarana), and higher-canopy, more dense and humid forest. The area is generally flat, with isolated rocky elevations 45–365 m high, and a large portion is subject to seasonal flooding. Forests are distributed along water bodies and on the higher terrain. Mean annual rainfall is 1750 mm, and concentrates in the rainy season, from April to August. A relatively extended dry season occurs from September to March. Mean annual temperature is 32 ◦ C (Machado et al., 2004). A 25-km2 trail system with a 1 km × 1 km grid resolution was installed in the northeast of the park in 2006 (http://ppbio.inpa.gov.br), making easy to walk on the forest and enabling direct observations of flora and fauna. On the morning of March 05, 2009, one of us (MD) and an experi- enced field technician were walking slowly (approx. 1 km/h) along one of the trails of the 25-km2 trail grid, as part of a visual-sampling survey of medium-sized and large mammals. At 08:25 solar time, in an area of campinarana forest we spotted an ocelot near the trail, laying on the ground. As we approached, the ocelot calmly rose and walked away into the forest. About 4 m away from the ocelot’s bed we located a fresh carcass of a large Linnaeus’s two-toed sloth which had an estimated weight of 7 kg. Scattered hair tufts around the carcass suggested the hairs of the sloth were plucked, as ocelots are reported to do with bird feathers and long-haired mammals (Leyhausen, 1979). The sloth lacked the braincase (but not the mandible), the eaten portion being about 200 g. The remaining body length was 60 cm. We were unable to find any other wound on the sloth’s body, so it was probably killed by a bite on the nape or the head, as do most felids, including ocelots (Leyhausen, 1979). Felids also usually begin to eat their prey by the head, except if they are unable to break the braincase bones (Leyhausen, 1979). The close proximity of the predator’s resting place to its partially eaten prey could be interpreted as some kind of prey guarding. We left the place after several minutes. Nine hours later (at 17:15 h), the sloth carcass had been moved 35 m far of the trail. The neck, shoulders and part of the chest had been eaten (about 1 kg). The content of the stomach laid 3 m away from the body. Another of us (JC) returned to the same spot on the morning of the following day, observing from a distance that the carcass had been moved again and finding new tracks of two different ocelots (spe- cific assignation based on track measurements; Calzada et al., 2007) in a print trap installed 200 m away from the carcass location. The tracks were apparently coming from the direction of the carcass. Observations of pairs of ocelots are not rare (see a short review in Mondolfi, 1986), so two individuals could have been eating the sloth. Three days after the finding, only the harder parts of skin and the bones of the extremities remained, covered with plenty of flies and larvae. No signs of other scavengers were detected. Linnaeus’s two-toed sloths live in the canopy and are a com- mon prey of harpy eagles (Harpia harpyja) (Galetti and de Carvalho, 2000; Mún˜ iz-López, 2008). However, they descend to the ground to defecate and to move from one tree to the other, being then exposed to many terrestrial and semi-arboreal predators (Adam, 1999). Among 774 vertebrate prey items recorded in six studies of ocelot diet (we excluded those in Cockscomb Basin of Belize, reviewed by Sunquist and Sunquist, 2002, and the tropical deciduous forest in Jalisco, Mexico, by Villa-Meza et al., 2002, as presumably sloths do not live there), we have found only one sloth record (Brady- pus variegatus, the brown-throated three-toed sloth; among 30 vertebrate prey items recorded in the Atlantic rainforest of South- east Brazil; Wang, 2002). No sloth appeared among the prey of ocelots in Iguazú National Park in Brazil (minimum number of ver- tebrate prey recorded, vp = 75) and Guárico in Venezuela (vp = 269), reviewed by Sunquist and Sunquist (2002), Manu National Park in Peru (vp = 177; Emmons, 1987), Araucaria pine forest of Paraná in Southern Brazil (vp = 99; Abreu et al., 2008) and Caratinga Biologi- cal Reserve in Minas Gerais, Brazil (vp = 124; Bianchi and Mendes, 2007). The exception to this common pattern is the already quoted situation on Barro Colorado island in Panama, where sloths can be especially abundant and small prey especially scarce as a result of competition and mesopredator release (Moreno et al., 2006). However, pumas (Puma concolor) and jaguars are common in Viruá (authors, unpublished data), hence a focus of ocelots on small prey should be expected here. Our observation is exceptional because continental ocelots only very rarely capture sloths (maybe this is the first record of the species Choloepus didactylus as an ocelot’s prey) and because none aspect of the behaviour of the species in the wild while dealing with a large prey was previously described.
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