Visual Laterality of Calf–Mother Interactions in Wild Whales

Behavioral laterality is known for a variety of vertebrate and invertebrate animals. Laterality in social interactions has been described for a wide range of species including humans. Although evidence and theoretical predictions indicate that in social species the degree of population level laterality is greater than in solitary ones, the origin of these unilateral biases is not fully understood. It is especially poorly studied in the wild animals. Little is known about the role, which laterality in social interactions plays in natural populations. A number of brain characteristics make cetaceans most suitable for investigation of lateralization in social contacts.) in the greatest breeding aggregation in the White Sea. Here we show that young calves (in 29 individually identified and in over a hundred of individually not recognized mother-calf pairs) swim and rest significantly longer on a mother's right side. Further observations along with the data from other cetaceans indicate that found laterality is a result of the calves' preference to observe their mothers with the left eye, i.e., to analyze the information on a socially significant object in the right brain hemisphere.Data from our and previous work on cetacean laterality suggest that basic brain lateralizations are expressed in the same way in cetaceans and other vertebrates. While the information on social partners and novel objects is analyzed in the right brain hemisphere, the control of feeding behavior is performed by the left brain hemisphere. Continuous unilateral visual contacts of calves to mothers with the left eye may influence social development of the young by activation of the contralateral (right) brain hemisphere, indicating a possible mechanism on how behavioral lateralization may influence species life and welfare. This hypothesis is supported by evidence from other vertebrates

NEOTROPICAL XENARTHRANS: a data set of occurrence of xenarthran species in the Neotropics

Xenarthrans – anteaters, sloths, and armadillos – have essential functions for ecosystem maintenance, such as insect control and nutrient cycling, playing key roles as ecosystem engineers. Because of habitat loss and fragmentation, hunting pressure, and conflicts with 24 domestic dogs, these species have been threatened locally, regionally, or even across their full distribution ranges. The Neotropics harbor 21 species of armadillos, ten anteaters, and six sloths. Our dataset includes the families Chlamyphoridae (13), Dasypodidae (7), Myrmecophagidae (3), Bradypodidae (4), and Megalonychidae (2). We have no occurrence data on Dasypus pilosus (Dasypodidae). Regarding Cyclopedidae, until recently, only one species was recognized, but new genetic studies have revealed that the group is represented by seven species. In this data-paper, we compiled a total of 42,528 records of 31 species, represented by occurrence and quantitative data, totaling 24,847 unique georeferenced records. The geographic range is from the south of the USA, Mexico, and Caribbean countries at the northern portion of the Neotropics, to its austral distribution in Argentina, Paraguay, Chile, and Uruguay. Regarding anteaters, Myrmecophaga tridactyla has the most records (n=5,941), and Cyclopes sp. has the fewest (n=240). The armadillo species with the most data is Dasypus novemcinctus (n=11,588), and the least recorded for Calyptophractus retusus (n=33). With regards to sloth species, Bradypus variegatus has the most records (n=962), and Bradypus pygmaeus has the fewest (n=12). Our main objective with Neotropical Xenarthrans is to make occurrence and quantitative data available to facilitate more ecological research, particularly if we integrate the xenarthran data with other datasets of Neotropical Series which will become available very soon (i.e. Neotropical Carnivores, Neotropical Invasive Mammals, and Neotropical Hunters and Dogs). Therefore, studies on trophic cascades, hunting pressure, habitat loss, fragmentation effects, species invasion, and climate change effects will be possible with the Neotropical Xenarthrans dataset

From left to right: Humans only?

Adult humans map numbers onto a mental number line oriented from left to right. (Dehaene, 1997, Dehaene et al., 2008). It is not clear if this mapping is of cultural or educational nature, or if it rather is a universal intuition, also present in non-human species. In a task requiring the identification of a certain object on the exclusive basis of its ordinal position in a series of identical objects, few-days-old chicks showed a leftward bias when the spatial orientation of the series was changed from training to test (Rugani et al., 2007). Here, two bird species (i.e. the domestic chick and the Clark\u2019s nutcracker) were tested in a similar task. Birds were trained to identify the 4th or the 6th element in a series of 16 fixed and identical elements, oriented sagittally with respect to the bird in the starting point. When the orientation of the series remained as for the training, birds\u2019 performance was above chance level. When generalizing to the series rotated by 90\ub0, birds\u2019 performance was also for pecking at the correct positions significantly above chance level, but now birds displayed a clear bias for locating such positions in the left hemispace. Birds thus exhibited a left-side bias similar to that displayed by humans. It may be the case that a right hemispheric dominance is at play in this sort of tasks, with the left visual hemifield controlling birds\u2019 behaviour, nevertheless the resemblance with the human\u2019s behaviour is not negligible

From left to right: Humans only?

Adult humans map numbers onto a mental number line oriented from left to right. It is not clear if this mapping is of cultural nature, or if it rather is a universal intuition, also present in non-human species. In a task requiring the identification of an object on the basis of its ordinal position in a series of identical objects, few-days-old chicks showed a leftward bias when the spatial orientation of the series was changed from training to test. Here, two bird species (i.e. the domestic chick and the Clark\u2019s nutcracker) were tested in a similar task. Birds were trained to identify the 4th or the 6th element in a series of 16 fixed and identical elements, oriented sagittally with respect to the bird in the starting point. When the orientation of the series remained as for the training, birds\u2019 performance was above chance. When generalizing to the series rotated by 90\ub0, birds\u2019 performance was also for pecking at the correct positions significantly above chance, but now birds displayed a bias for locating such positions in the left hemispace. Birds thus exhibited a left-side bias similar to that displayed by humans. It may be the case that a right hemispheric dominance is at play in this sort of tasks, with the left visual hemifield controlling birds\u2019 behaviour, but the resemblance with the human\u2019s behaviour is not negligible

The Mind Through Chick Eyes : Memory, Cognition and Anticipation

To understand the animal mind, we have to reconstruct how animals recognize the external world through their own eyes. For the reconstruction to be realistic, explanations must be made both in their proximate causes (brain mechanisms) as well as ultimate causes (evolutionary backgrounds). Here, we review recent advances in the behavioral, psychological, and system-neuroscience studies accomplished using the domestic chick as subjects. Diverse behavioral paradigms are compared (such as filial imprinting, sexual imprinting, one-trial passive avoidance learning, and reinforcement operant conditioning) in their behavioral characterizations (development, sensory and motor aspects of functions, fitness gains) and relevant brain mechanisms. We will stress that common brain regions are shared by these distinct paradigms, particularly those in the ventral telencephalic structures such as AIv (in the archistriatum) and LPO (in the medial striatum). Neuronal ensembles in these regions could code the chick's anticipation for forthcoming events, particularly the quality/quantity and the temporal proximity of rewards. Without the internal representation of the anticipated proximity in LPO, behavioral tolerance will be lost, and the chick makes impulsive choice for a less optimized option. Functional roles of these regions proved compatible with their anatomical counterparts in the mammalian brain, thus suggesting that the neural systems linking between the memorized past and the anticipated future have remained highly conservative through the evolution of the amniotic vertebrates during the last 300 million years. With the conservative nature in mind, research efforts should be oriented toward a unifying theory, which could explain behavioral deviations from optimized foraging, such as "naïve curiosity," "contra-freeloading," "Concorde fallacy," and "altruism.

A precise optical determination of nanoscale diameters of semiconductor nanowires

Electrical and optical properties of semiconducting nanowires (NWs) strongly depend on their diameters. Therefore, a precise knowledge of their diameters is essential for any kind of device integration. Here, we present an optical method based on dark field optical microscopy to easily determine the diameters of individual NWs with an accuracy of a few nanometers and thus a relative error of less than 10%. The underlying physical principle of this method is that strong Mie resonances dominate the optical scattering spectra of most semiconducting NWs and can thus be exploited. The feasibility of this method is demonstrated using GaAs NWs but it should be applicable to most types of semiconducting NWs as well. Dark field optical microscopy shows that even slight tapering of the NWs, i.e. diameter variations of a few nanometers, can be detected by a visible color change. Abrupt diameter changes of a few nanometers, as they occur for example when growth conditions vary, can be determined as well. In addition a profound analysis of the elastic scattering properties of individual GaAs NWs is presented theoretically using Mie calculations as well as experimentally by dark field microscopy. This method has the advantage that no vacuum technique is needed, a fast and reliable analysis is possible based on cheap standard hardware