The means of orientation is studied in the Vietnamese pygmy dormouse Typhlomys chapensis,a poorly known enigmatic semi-fossorial semi-arboreal rodent.Data on eye structure are presented,which prove that Typhlomys(tran...The means of orientation is studied in the Vietnamese pygmy dormouse Typhlomys chapensis,a poorly known enigmatic semi-fossorial semi-arboreal rodent.Data on eye structure are presented,which prove that Typhlomys(translated as“the blind mouse”)is incapable of object vision:the retina is folded and retains no more than 2500 ganglion cells in the focal plane,and the optic nerve is subject to gliosis.Hence,Typhlomys has no other means for rapid long-range orientation among tree branches other than echolocation.Ultrasonic vocalization recordings at the frequency range of 50-100 kHz support this hypothesis.The vocalizations are represented by bouts of up to 7 more or less evenly-spaced and uniform frequency-modulated sweep-like pulses in rapid succession.Structurally,these sweeps are similar to frequency-modulated ultrasonic echolocation calls of some bat species,but they are too faint to be revealed with a common bat detector.When recording video simultaneously with the ultrasonic audio,a significantly greater pulse rate during locomotion compared to that of resting animals has been demonstrated.Our findings of locomotion-associated ultrasonic vocalization in a fast-climbing but weakly-sighted small mammal ecotype add support to the“echolocation-first theory”of pre-flight origin of echolocation in bats.展开更多
It is important to predict how many individuals of a predator species can survive in a given area on the basis of prey sufficiency and to compare predictive estimates with actual numbers to understand whether or not k...It is important to predict how many individuals of a predator species can survive in a given area on the basis of prey sufficiency and to compare predictive estimates with actual numbers to understand whether or not key threats are related to prey availability.Rugged terrain and low detection probabilities do not allow for the use of traditional prey count techniques in mountain areas.We used presence–absence occupancy modeling and camera-trapping to estimate the abundance and densities of prey species and regression analysis to predict leopard(Panthera pardus)densities from estimated prey biomass in the mountains of the Nuvadi area,Meghri Ridge,southern Armenia.The prey densities were 12.94±2.18 individuals km–2 for the bezoar goat(Capra aegagrus),6.88±1.56 for the wild boar(Sus scrofa)and 0.44±0.20 for the roe deer(Capreolus capreolus).The detection probability of the prey was a strong function of the activity patterns,and was highest in diurnal bezoar goats(0.59±0.09).Based on robust regression,the estimated total ungulate prey biomass(720.37±142.72 kg km–2)can support a leopard density of 7.18±3.06 individuals 100 km–2.The actual leopard density is only 0.34 individuals 100 km–2(i.e.one subadult male recorded over the 296.9 km2),estimated from tracking and camera-trapping.The most plausible explanation for this discrepancy between predicted and actual leopard density is that poaching and disturbance caused by livestock breeding,plant gathering,deforestation and human-induced wild fires are affecting the leopard population in Armenia.展开更多
基金approved by the Committee of Bio-ethics of the Lomonosov Moscow State University(research protocol no.2011-36)Video processing was performed with support of the Russian Science Foundation(project 14-50-00029“Scientific basis of the national biobank-depository of the living systems”)+1 种基金Acoustic analysis was supported by the Russian Science Foundation(project 14-14-00237)the Program of Basic Research of the Presidium of the Russian Academy of Sciences“Wildlife:Current Status and Problems of Development.”。
文摘The means of orientation is studied in the Vietnamese pygmy dormouse Typhlomys chapensis,a poorly known enigmatic semi-fossorial semi-arboreal rodent.Data on eye structure are presented,which prove that Typhlomys(translated as“the blind mouse”)is incapable of object vision:the retina is folded and retains no more than 2500 ganglion cells in the focal plane,and the optic nerve is subject to gliosis.Hence,Typhlomys has no other means for rapid long-range orientation among tree branches other than echolocation.Ultrasonic vocalization recordings at the frequency range of 50-100 kHz support this hypothesis.The vocalizations are represented by bouts of up to 7 more or less evenly-spaced and uniform frequency-modulated sweep-like pulses in rapid succession.Structurally,these sweeps are similar to frequency-modulated ultrasonic echolocation calls of some bat species,but they are too faint to be revealed with a common bat detector.When recording video simultaneously with the ultrasonic audio,a significantly greater pulse rate during locomotion compared to that of resting animals has been demonstrated.Our findings of locomotion-associated ultrasonic vocalization in a fast-climbing but weakly-sighted small mammal ecotype add support to the“echolocation-first theory”of pre-flight origin of echolocation in bats.
文摘It is important to predict how many individuals of a predator species can survive in a given area on the basis of prey sufficiency and to compare predictive estimates with actual numbers to understand whether or not key threats are related to prey availability.Rugged terrain and low detection probabilities do not allow for the use of traditional prey count techniques in mountain areas.We used presence–absence occupancy modeling and camera-trapping to estimate the abundance and densities of prey species and regression analysis to predict leopard(Panthera pardus)densities from estimated prey biomass in the mountains of the Nuvadi area,Meghri Ridge,southern Armenia.The prey densities were 12.94±2.18 individuals km–2 for the bezoar goat(Capra aegagrus),6.88±1.56 for the wild boar(Sus scrofa)and 0.44±0.20 for the roe deer(Capreolus capreolus).The detection probability of the prey was a strong function of the activity patterns,and was highest in diurnal bezoar goats(0.59±0.09).Based on robust regression,the estimated total ungulate prey biomass(720.37±142.72 kg km–2)can support a leopard density of 7.18±3.06 individuals 100 km–2.The actual leopard density is only 0.34 individuals 100 km–2(i.e.one subadult male recorded over the 296.9 km2),estimated from tracking and camera-trapping.The most plausible explanation for this discrepancy between predicted and actual leopard density is that poaching and disturbance caused by livestock breeding,plant gathering,deforestation and human-induced wild fires are affecting the leopard population in Armenia.
