Author
Elke Zimmermann
Other affiliations: German Primate Center, Hochschule Hannover, University of Veterinary Medicine Hanover
Bio: Elke Zimmermann is an academic researcher from University of Veterinary Medicine Vienna. The author has contributed to research in topics: Lemur & Mouse lemur. The author has an hindex of 43, co-authored 148 publications receiving 4795 citations. Previous affiliations of Elke Zimmermann include German Primate Center & Hochschule Hannover.
Topics: Lemur, Mouse lemur, Microcebus murinus, Population, Cheirogaleidae
Papers published on a yearly basis
Papers
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TL;DR: Results indicate that there were two main periods of selection-driven evolutionary change in laughter within the Hominidae, to a smaller degree, among the great apes and, most distinctively, after the separation of hominins from the last common ancestor with chimpanzees and bonobos.
190 citations
TL;DR: Elements of both biogeographic models are combined in a new hypothesis that aims to explain the speciation process leading to the present distribution of mouse lemurs in Madagascar.
152 citations
TL;DR: The sleeping site ecology of two sympatric mouse lemur species in northwestern Madagascar during the second half of the dry season with respect to the type, quality, and usage pattern of the sleeping sites, as well as to social sleeping habits and response to potential threats is investigated.
Abstract: We investigated the sleeping site ecology of two sympatric mouse lemur species (Microcebus murinus and M. ravelobensis) in northwestern Madagascar during the second half of the dry season with respect to the type, quality, and usage pattern of the sleeping sites, as well as to social sleeping habits and response to potential threats. The type and quality of the sleeping sites differed between the two species. M. murinus used protected wooden shelters (tree holes) more frequently than M. ravelobensis, and M. ravelobensis used a broader variety of less protected sites (e.g., branches, lianas, and leaves) than M. murinus. Whereas male M. murinus usually slept alone, and female M. murinus mostly slept in groups, both sexes of M. ravelobensis slept in mixed-sex sleeping groups. M. murinus relied on crypsis in their sleeping sites, whereas M. ravelobensis regularly showed a flight response to the approach of an observer. This behavioral difference could indicate an adaptation to a higher predation risk in less protected sleeping sites. Whereas female M. murinus showed a high site fidelity, male M. murinus and both sexes of M. ravelobensis frequently changed their sleeping sites, which may also be interpreted as an antipredator strategy. The results are discussed with respect to three possible ecological explanations: interspecies competition, restricted resource availability, and niche differentiation. The latter is the most likely explanation for these interspecific differences. Am. J. Primatol. 59:139–151, 2003. © 2003 Wiley-Liss, Inc.
145 citations
TL;DR: The underlying study indicates that sleeping sites may be a restricted and defendable resource for grey mouse lemurs and gives new insights into the distribution patterns and social organization of this species.
Abstract: Sleeping sites are a potentially important resource for grey mouse lemurs since they are confronted with high daily temperature fluctuations and a high predation pressure. In order to determine the existence and degree of resource competition, sleeping site characteristics, locations, and usage patterns as well as sleeping group compositions were investigated in a 3 month field study in a dry deciduous forest of northwestern Madagascar. The daily sleeping sites of females were on average better insulated and safer than those of males. Males used more sleeping sites and changed the site more often than females. During the whole study, males slept alone, whereas the females formed stable sleeping groups in on average 83.7% of the days. Sex-specific differences in usage patterns might be explained by intersexual resource competition and female dominance and could possibly be related to differential parental investment of the sexes. The underlying study indicates that sleeping sites may be a restricted and defendable resource for grey mouse lemurs. The investigation gives new insights into the distribution patterns and social organization of this species.
140 citations
TL;DR: The results indicate the importance of microhabitat analyses for the understanding of distribution patterns of species and for successful conservation planning.
Abstract: Understanding processes affecting the distribution and abundance of organisms is a central issue in ecology and conservation biology. In northwestern Madagascar, we found an uneven distribution pattern of the golden-brown mouse lemur (Microcebus ravelobensis) and the grey mouse lemur (M. murinus). In one area (JBA) the two species lived sympatrically, whereas in another forest area (JBB) Microcebus ravelobensis occurred exclusively. To investigate whether differences in forest structure may explain this uneven distribution, we conducted a microhabitat analysis and related it to specific distribution. In JBA the habitat of Microcebus ravelobensis was characterized by a higher percentage of trees with many lianas and a higher cover of the herb layer, whereas that of M. murinus had a higher number of trees with a diameter at breast height (DBH) >10 cm. The comparison of the forest structure of the microhabitats of the two species between JBA and JBB revealed further differences. The cover of the overstory, the percentage of trees without lianas and the number of larger trees (DBH >10 cm) among the microhabitats were higher for Microcebus murinus in JBA than for M. ravelobensis in JBB whereas the microhabitats of M. ravelobensis at the two sites did not differ concerning these vegetation structures. Differences between the two species coincide with those of resources important for survival. Our results indicate the importance of microhabitat analyses for the understanding of distribution patterns of species and for successful conservation planning.
130 citations
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Journal Article•
TL;DR: It is suggested that the natural selection against large insertion/deletion is so weak that a large amount of variation is maintained in a population.
11,521 citations
TL;DR: It is proposed here that an observation/execution matching system provides a necessary bridge from'doing' to'communicating', as the link between actor and observer becomes a link between the sender and the receiver of each message.
2,675 citations
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1,368 citations
Journal Article•
TL;DR: For instance, this paper found that brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal cortex.
Abstract: A MUCH debated question is whether sex differences exist in the functional organization of the brain for language1–4. A long-held hypothesis posits that language functions are more likely to be highly lateralized in males and to be represented in both cerebral hemispheres in females5,6, but attempts to demonstrate this have been inconclusive7–17. Here we use echo-planar functional magnetic resonance imaging18–21 to study 38 right-handed subjects (19 males and 19 females) during orthographic (letter recognition), phonological (rhyme) and semantic (semantic category) tasks. During phonological tasks, brain activation in males is lateralized to the left inferior frontal gyrus regions; in females the pattern of activation is very different, engaging more diffuse neural systems that involve both the left and right inferior frontal gyrus. Our data provide clear evidence for a sex difference in the functional organization of the brain for language and indicate that these variations exist at the level of phonological processing.
1,247 citations
TL;DR: It is argued that the conflict between hosts and viruses has led to the invention and diversification of molecular arsenals, which, in turn, promote the cellular co-option of endogenous viruses.
Abstract: Recent studies have uncovered myriad viral sequences that are integrated or 'endogenized' in the genomes of various eukaryotes. Surprisingly, it appears that not just retroviruses but almost all types of viruses can become endogenous. We review how these genomic 'fossils' offer fresh insights into the origin, evolutionary dynamics and structural evolution of viruses, which are giving rise to the burgeoning field of palaeovirology. We also examine the multitude of ways through which endogenous viruses have influenced, for better or worse, the biology of their hosts. We argue that the conflict between hosts and viruses has led to the invention and diversification of molecular arsenals, which, in turn, promote the cellular co-option of endogenous viruses.
741 citations