Keyword: Chrysocyon brachyurus

Influence of interference competition and seasonality on the activity patterns of carnivorous mammals in the Brazilian Cerrado

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The pattern of activity of species can be influenced by environmental and biological factors and can change according to seasonality. In general, the activity pattern of species of the order Carnivora is influenced by air temperature and humidity, prey activity pattern, human presence, and competition. To answer whether there is temporal niche segregation between Cerrado carnivore species and whether the pattern of activity of Cerrado carnivores changes between the two well-marked seasons of the biome, we collected data on native carnivores with camera traps over a year. Species were active mainly in the twilight and night periods, with high overlap in their activity schedules. Activity patterns of the crab-eating fox and puma were significantly different, which indicates that the canid may be avoiding the competing species in time to avoid agonistic interactions. Furthermore, the peak activity periods of the four carnivore species do not overlap, suggesting that competition is a secondary mechanism determining the activity pattern of these species. The activity patterns of the species did not differ significantly between seasons. However, the crab-eating fox tended to be more diurnal in the rainy season, while the puma tended to be more diurnal in the dry season.

Influência da competição de interferência e da sazonalidade nos padrões de atividade de mamíferos carnívoros no cerrado brasileiro. O padrão de atividade das espécies pode ser influenciado por fatores ambientais e biológicos e mudar conforme a sazonalidade. Espécies da ordem Carnivora em geral têm o padrão de atividade influenciado pela temperatura e umidade do ar, pelo horário de atividade das presas, pela presença humana e pela competição. Para responder se há segregação de nicho temporal entre espécies de carnívoros do Cerrado e se o padrão de atividade dos carnívoros do Cerrado muda entre as duas bem-marcadas estações do bioma, coletamos dados de carnívoros nativos com armadilhas fotográficas ao longo de um ano. As espécies foram ativas principalmente nos períodos crepuscular e noturno, com alta sobreposição do horário de atividade. Os padrões de atividade do cachorro-do-mato e da suçuarana foram estatisticamente diferentes, o que indica que o canídeo pode estar evitando a espécie competidora no tempo para evitar interações agonísticas. Além disso, os horários de pico de atividade das quatro espécies de carnívoros não se sobrepõem, sugerindo que a competição é um mecanismo secundário na determinação do padrão de atividade dessas espécies. Os padrões de atividade das espécies não diferiram significativamente entre as estações, mas o cachorro-do-mato mostrou tendência a ser mais diurno na estação chuvosa, enquanto a suçuarana tendeu a ser mais diurna na estação seca.

Graphical abstract for the article “Influence of interference competition and seasonality on the activity patterns of carnivorous mammals in the Brazilian Cerrado” (Oliveira Machado et al., 2023)

Mountain lion Puma concolor attacks on a maned wolf Chrysocyon brachyurus and a domestic dog in a forestry system

Two independent attacks of mountain lions Puma concolor (Linnaeus, 1771) on different canid species are reported in this note. One of the canids was a sub-adult captive maned wolf Chrysocyon brachyurus (Illiger, 1815), revealing skull damaged by canine tooth perforation and several bruises along the body. Examination of the wounds and the killing site provided reasonable details on how the attack was conducted. The mountain lion grabbed the maned wolf from behind with both forepaws, and killed it with a bite at the nape of the neck and at the back of the skull. From the low disturbance of the site, the killing must have been accomplished fast and without much struggle. The second attack was on a domestic dog, in a house yard. It was carried out by a sub-adult, abnormal female mountain lion, which was killed with a club by the property owner while charging. The inability to hunt wild prey, due to physical impairment, was certainly what motivated the mountain lion to attack the domestic dog. The aim of this article is to provide information on mountain lion interactions with non-prey species, and to discuss the implications of the proximity of mountain lions to human dwellings.

Ataque de onça-parda Puma concolor a um lobo-guará Chrysocyon brachyurus e a um cachorro doméstico em um sistema florestal. Dois ataques independentes de onça-parda Puma concolor (Linnaeus, 1771) a duas espécies de canídeos são descritas neste artigo. O lobo-guará Chrysocyon brachyurus (Illiger, 1815), semiadulto e criado em cativeiro, revelou danos no crânio por perfuração de caninos e vários ferimentos no corpo depois de necrópsia. O exame de ferimentos e do local do ataque permitiram reconstituir o ocorrido com detalhe aproximado. A onça-parda agarrou o lobo-guará pela parte anterior usando as duas patas dianteiras, em seguida mordendo o pescoço e a parte posterior do crânio do canídeo. Pelo baixo distúrbio provocado no local, o ataque deve ter transcorrido rápido e sem muita luta. O segundo ataque foi a um cachorro doméstico, ocorrido no jardim de uma casa. Foi provocado por uma onça-parda fêmea e com deformidades, morta pelo proprietário com repetidas batidas de bastão no momento do ataque. A impossibilidade de caçar presas silvestres devido a problemas físicos foi certamente o que provocou a investida da onça. O objetivo deste artigo é o de fornecer informação sobre a interação de onças-parda com espécies que não fazem parte de sua dieta alimentar, e discutir as implicações da proximidade de onças-parda a habitações humanas.

Small mammal selection and functional response in the diet of the maned wolf, Chrysocyon brachyurus (Mammalia: Canidae), In southeast Brazil

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Data reported here are intended to describe patterns of predation by a solitary hunter, as well as to bring new insights into the predator-prey relationship in the Neotropical region. The goal of this study was to verify if there was small mammal selection in the diet of the maned wolf. Also, we attempt to test for a functional response in relation to the consumption of small mammals. The study was carried out in the Ecological Station of Itirapina (ESI), São Paulo, Brazil. Faeces collection and small mammal abundance survey by pitfall trapping were conducted simultaneously during 2000–2002. The maned wolf was selective in the consumption of small mammals. Calomys tener and Oligoryzomys nigripes (Muridae) were consumed less than expected by chance, whereas Clyomys bishopi (Echimyidae) was preyed on more than expected. We did not detect a clear functional response by this canid in the ESI to overall shifts in abundance of small mammals. However, prey switching was detected by an increase in diet diversity in the wet season when small mammals become less available.

La distribución de Chrysocyon brachyurus (Illiger, 1811) (Mammalia: Carnivora: Canidae) durante el Holoceno en la Argentina: implicancias paleoambientales

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A partir de la distribución actual de la especie y de los factores climáticos (temperatura y precipitaciones) en el área, se evalúa y describe el registro paleontológico y arqueológico, así como los datos históricos y etnohistóricos con el objetivo de reconstruir su distribución durante el Holoceno. Con el mismo fin se discuten las evidencias sobre cambios climáticos en el último milenio, tanto a escala regional como global. Además, se da a conocer un nuevo registro de C. brachyurus encontrado en sedimentos del Holoceno tardío en un sitio arqueológico del sudeste de la región pampeana. El nuevo resto (un metatarsiano quinto) constituye el registro más austral de C. brachyurus, encontrándose a 500 km al sur del registro fósil más cercano, y a más de 1000 km de su área de distribución actual. A su vez, corresponde al registro más antiguo de la República Argentina. La revisión bibliográfica no permitió encontrar evidencias que sustenten la presencia de C. brachyurus al sur de su área de distribución actual en tiempos históricos. La distribución actual de C. brachyurus, y probablemente la del Holoceno tardío, está vinculada con temperaturas medias no inferiores a 19 °C y precipitaciones medias de amplio rango (entre 1500 y 550 mm). La presencia de esta especie durante el Holoceno estaría relacionada con momentos de menor aridez y mayor temperatura.

The distribution of Chrysocyon brachyurus (Illiger, 1811) (Mammalia: Carnivora: Canidae) in Argentina during the Holocene: paleoenviromental implications. On the basis of the current distribution of C. brachyurus and the climatic factors (temperature and precipitation) of the area, the paleontological and archaeological record as well as the historical and etnohistorical data are evaluated and described in order to reconstruct its distribution during the Holocene. The evidences of climatic changes in the area are discussed within regional and global scale. It is also reported a new record of C. brachyurus found in sediments of the Late Holocene of an archaeological site in the southeastern Pampean region. The new material (a fifth metatarsal) is the southernmost record of C. brachyurus, being 500 km south from the nearest fossil record, and more than 1000 km farther south from the present distribution area. In addition, it is the oldest record in Argentina. The bibliographical revision showed that there are no evidences supporting the presence of C. brachyurus in historical times south of the area of its current distribution. The current distribution of C. brachyurus, and probably that of the Late Holocene, is linked to mean temperatures higher than 19 °C and mean precipitation between 1500 and 550 mm. The presence of this species during the Holocene would be related to moments of less aridity and higher temperatures.

Registro de Chrysocyon brachyurus (Carnivora: Canidae) en contextos arqueológicos en el noreste de la Provincia de Buenos Aires

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Se da a conocer un fragmento mandibular y un canino inferior de Chrysocyon brachyurus procedentes del sitio arqueológico La Bellaca 2, en el noreste de la provincia de Buenos Aires. En Argentina, esta especie se distribuye aproximadamente hasta la latitud 30° S. Sin embargo, su distribución en tiempos pretéritos ha sido ampliada sobre la base de narraciones de viajeros y vocablos indígenas que harían referencia a este cánido y por algunos restos provenientes de sitios arqueológicos. No obstante, el material de estos sitios generalmente ha sido referido con dudas a esta especie. Los restos del sitio La Bellaca 2 constituyen el registro más austral asignado con seguridad a C. brachyurus.

Record of Chrysocyon brachyurus (Carnivora: Canidae) in archaeological contexts in northeastern Buenos Aires Province. In this report we present a mandibular fragment and a lower canine of Chrysocyon brachyurus from the archaeological site La Bellaca 2, northeastern Buenos Aires Province. In Argentina, this species is distributed southward as far as 30° S. Notwithstanding, the distribution of this species in the past was extended based upon reports of travelers and native words, as well as upon some archaeological remains. Nevertheless, these archaeological remains were usually referred with doubt to this species. The fragments from the site La Bellaca 2 constitute the southernmost record assigned with certainty to C. brachyurus.