Search results for "Carnivora"
showing 10 items of 26 documents
Interrelations between globus pallidus and hippocampal epilepsy in the cat (1)
1984
AbstractElectrically induced afterdischarge (ADs) were evoked in the cats' dorsal hippocampus. The action of the conditioning prestimulation of the pallidus nucleus on AD duration was studied. A significant facilitatory influence was observed when pallidal conditioning stimulation immediately preceded hippocampal test stimulation. The time course of the phenomenon showed a decrease of the conditioning action when the interval between the two stimulations increased: complete disappearance of the effect occurred after about 800 ms. Results are discussed as far as functional relationships between basal ganglia and rhinencephalic system are concerned.
Correlation of carnassial tooth size and body weight in recent carnivores (mammalia)
1988
The correlation between the lower carnassial crown area and the body weight is examined for modern carnivores. It is very high, but the ursids and felids show a relationship different from the other carnivore families. Some exceptions are discussed. The possibility of predicting body weight for fossils is given.
Kretzoiarctos gen. nov., the oldest member of the giant panda clade
2012
The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8–7 mya) was recognized as the oldest undoubted me…
Response of an arctic predator guild to collapsing lemming cycles
2012
6 pages; International audience; Alpine and arctic lemming populations appear to be highly sensitive to climate change, and when faced with warmer and shorter winters, their well-known high-amplitude population cycles may collapse. Being keystone species in tundra ecosystems, changed lemming dynamics may convey significant knock-on effects on trophically linked species. Here, we analyse long-term (1988-2010), community-wide monitoring data from two sites in high-arctic Greenland and document how a collapse in collared lemming cyclicity affects the population dynamics of the predator guild. Dramatic changes were observed in two highly specialized lemming predators: snowy owl and stoat. Follo…
Coprolites in natural traps : direct evidence of bone-eating carnivorans from the Late Miocene Batallones-3 site, Madrid, Spain
2021
We describe two carnivoran coprolites found in the pseudokarst natural carnivore trap of Batallones-3, from the Late Miocene of Spain. The larger one, comprising multiple indistinguishable fragments of broken and corroded bones, indicates that the producer of the dropping might have been highly capable of crushing the softer parts of large bones. On the other hand, the smaller one shows several relatively larger and more complete bone fragments, thus exhibiting a greater capacity to break and swallow large portions of bone. The external morphology of the large coprolite is similar to that of extant bears, whereas the smaller one more closely resembles that of the living insectivorous hyaeni…
Mesocarnivore community structuring in the presence of Africa's apex predator
2021
This work was supported by the Peace Parks Foundation; G.C.S. was funded by a doctoral grant from Fundacão para a Ciência e a Tecnologia (FCT: PD/BD/114037/2015); L.H.S. was supported by the National Research Foundation, South Africa (UID: 107099 and 115040) and by the African Institute for Conservation Ecology. Apex predator reintroductions have proliferated across southern Africa, yet their ecological effects and proposed umbrella benefits of associated management lack empirical evaluations. Despite a rich theory on top-down ecosystem regulation via mesopredator suppression, a knowledge gap exists relating to the influence of lions (Panthera leo) over Africa's diverse mesocarnivore (less …
Assessing host-parasite specificity through coprological analysis: a case study with species of Corynosoma (Acanthocephala: Polymorphidae) from marin…
2011
In this paper we report an investigation of the utility of coprological analysis as an alternative technique to study parasite specificity whenever host sampling is problematic; acanthocephalans from marine mammals were used as a model. A total of 252 scats from the South American sea lion, Otaria flavescens, and rectal faeces from 43 franciscanas, Pontoporia blainvillei, from Buenos Aires Province, were examined for acanthocephalans. Specimens of two species, i.e. Corynosoma australe and C. cetaceum, were collected from both host species. In sea lions, 78 out of 145 (37.9%) females of C. australe were gravid and the sex ratio was strongly female-biased. However, none of the 168 females of …
On the socio-sexual behaviour of the extinct ursid Indarctos arctoides: an approach based on its baculum size and morphology
2013
The fossil bacula, or os penis, constitutes a rare subject of study due to its scarcity in the fossil record. In the present paper we describe five bacula attributed to the bear Indarctos arctoides Depéret, 1895 from the Batallones-3 site (Madrid Basin, Spain). Both the length and morphology of this fossil bacula enabled us to make interpretative approaches to a series of ecological and ethological characters of this bear. Thus, we suggest that I. arctoides could have had prolonged periods of intromission and/or maintenance of intromission during the post-ejaculatory intervals, a multi-male mating system and large home range sizes and/or lower population density. Its size might also have he…
Effects of Substantia Nigra Stimulation on Electrical and Mechanical Activities of the Duodeno-Jejunal Loop, in the Cat
1985
The effect of substantia nigra stimulation on duodeno-jejunal intraluminal pressure and electrical activity was analysed in the cat. An inhibitory influence was noted to occur on both the intestinal pressure and the electrical response activity (ERA): the effect seemed to be in correlation with the stimulus parameters employed. After bilateral vagotomy, the inhibition remained substantially unchanged. The possibility of the existence of a sympathetic pathway mediating the effect is emphasized.
On the phylogeny and zoogeography of the leptarctines (Carnivora, Mammalia)
1982
A restudy of the skull and mandible ofLeptarctus neimenguensis Zhai from the Middle Miocene of China and the preparation of its auditory region led to the recognition of new features. The most important among them is the presence of a small suprameatal fossa partly hidden in the bony mastoid process corresponding to the structure described inPlesiogale andParagale (Schmidt-Kittler 1981) and representing the most primitive type of the mustelid middle ear.