Search results for "Rodent"

Late Pleistocene (MIS 3-4) climate inferred from micromammal communities and δ18O of rodents from Les Pradelles, France.

2013

The middle Paleolithic stratigraphic sequence of Les Pradelles (Charente, France) spans from the end of Marine Isotope Stage (MIS) 4 until the middle of MIS 3. Micromammal remains are present in all the stratigraphic levels, offering a rare opportunity to address the questions of both environmental and climatic fluctuations throughout this period. Climate modes were studied through the taphonomy, biodiversity and oxygen isotope compositions of phosphate (δ18O p ) from 66 samples of rodent tooth enamel. The δ18O p values from the lower sedimentary levels provide summer mean air temperatures of 19 ± 2°C (level 2/1) and of 16 ± 2°C (levels 2A, 2B and 4A). Within the middle of sequence (level 4…

Leishmaniasis in Norway Rats in Sewers, Barcelona, Spain.

2019

We detected Leishmania infantum in 98 Norway rats (Rattus norvegicus) trapped in parks and sewers of Barcelona, Spain. The 84 rats from the sewers showed a prevalence of 33.3% and up to 2,272 estimated parasites. These results, in the most abundant potential reservoir in cities, is of public health concern.

Evolutionary and developmental hypotheses in rodent dentition through time : the adaptive radiation of Arvicolinae (Rodentia)

2014

The evolution of mammalian dentition is defined by profound morphological modifications as occlusion and heterodonty. Among rodents, characterized by a reduced dental formula, arvicolines have a highly derived dentition, with prismatic and hypsodont molars. The aim of this Ph.D thesis is to explore various morphological innovations through developmental and adaptive aspects. Geometric morphometric methods were used on molars, incisors and mandibles to investigate the dynamics of development and evolution of dentition. A developmental model predicting molar proportions is tested and confirmed for the rodent order; it could be also extended to the premolar. The relationship between dental mor…

Attraction of kestrels to vole scent marks visible in ultraviolet light

1995

IN northern Europe, broad four-year oscillations in small rodent and raptor populations are synchronous over hundreds of square kilometers1–6. Crashes in vole populations can induce wide emigration (> 1,000 km) of their predators7 –9, but almost nothing is known about how predators rapidly detect areas of vole abundance. Here we report on laboratory and field experiments on voles (Microtus agrestis) and kestrels (Falco tinnunculus). Voles mark their runaways with urine and faeces, which are visible in ultraviolet light. Wild kestrels brought into captivity were able to detect vole scent marks in ultraviolet light but not in visible light. In the field, kestrels hunted preferentially near ex…

Hypsodont Myomiminae (Gliridae, Rodentia) from five new localities in the Lower Miocene Tudela Formation (Bardenas Reales, Ebro Basin, Spain) and the…

2012

The hypsodont Myomiminae Daams, 1981 (Gliridae) from the lower part of the Tudela Formation (Ebro Basin) are described. Five localities (CH1, CA2, CA3, CA4 and CC1) of this formation contain remains of the hypsodont genus Armantomy de Bruijn, 1966 and CC1 has also yielded Praearmantomys de Bruijn, 1966. Despite the poor material, we can identify the taxa A. cf. bijmai, A. daamsi (de Visser in Álvarez-Sierra, Daams, Lacomba, López Martínez, Van Der Meulen, Sesé & De Visser, 1991), A. cf. parsani, A. cf. jasperi and cf. P.crusafonti, which are characteristic of the Agenian and Ramblian continental stages. These data allow identification of the Agenian-Ramblian boundary in the Tudela Formation…

Can we understand human brain development from experimental studies in rodents?

2020

Animal models are needed to gain an understanding of the genetic, molecular, cellular, and network mechanisms of human brain development. In rodents, a large spectrum of in vitro and in vivo approaches allows detailed analyses and specific experimental manipulations for studying the sequence of developmental steps in corticogenesis. Neurogenesis, neuronal migration, cellular differentiation, programmed cell death, synaptogenesis, and myelination are surprisingly similar in the rodent cortex and the human cortex. Spontaneous EEG activity in the pre- and early postnatal human cortex resembles the activity patterns recorded with intracortical multi-electrode arrays in newborn rodents. This ear…

Enriched Environments for Rodents and their Interaction with Nicotine Administration

2012

An active lifestyle throughout the life cycle seems to delay cognitive aging and dementia and has also been evaluated as an intervention against addiction to cocaine and other drugs of abuse. In epidemiological studies with humans, it has proved difficult to separate the cognitive, social and physical components from other variables that influence lifestyle. Studies in animal models are useful for evaluating the impact of each of these factors and for uncovering the underlying mechanisms of the benefits of complex environments. Preclinical studies have employed the Environmental Enrichment paradigm (EE) which has been proposed as a preclinical model of positive life experiences in humans. E…

Age-related effects of chronic hantavirus infection on female host fecundity.

2015

1. Pathogens often cause detrimental effects to their hosts and, consequently, may influence host population dynamics that may, in turn, feed back to pathogen transmission dynamics. Understanding fitness effects of pathogens upon animal host populations can help to predict the risks that zoonotic pathogens pose to humans. 2. Here we determine whether chronic infection by Puumala hantavirus (PUUV) affects important fitness-related traits, namely the probability of breeding, reproductive effort and mother and offspring condition, in the bank vole (Myodes glareolus). Using 9 years empirical data in a PUUV endemic area in Central Finland, we found differences between reproductive characteristic…

2019

Basal cell carcinoma has a potential for early and late metastasis. Depending on the location of the primary site, the relevant lymphatic drainage routes have to be monitored. Regional lymph edema may be a first indicator for metastasizing disease.

The analysis of the diet composition of the barn owl Tyto alba (Scopoli, 1769) from the region of Brzeg, Opolskie Voivodeship (Poland)

2022

Research on the diet composition of the barn owl Tyto alba was conducted near the town of Przecza in the area of Lewin Brzeski (Opolskie Voivodeship. On the basis of 1158 bone elements, 14 species of small mammals were found, including 4 insectivorous species (Sorex araneus, Sorex minutus, Neomys fodiens, Cocidura suaveolens), 5 vole species (Microtus arvalis, Microtus agrestis, Arvicola terrestris, Myodes glareolus, Microtus oeconomus) and 5 mouse species (Mus musculus, Apodemus agrarius, Apodemus flavicolis, Apodemus sylvaticus, Micromys minutus). The diet was dominated by 3 species: Microtus arvalis, Sorex araneus and the Apodemus agrarius. The conducted research clearly shows that the T…