Editorial

These are heady times. As the new millennium dawns, the field of zoology is more exciting than ever. Phylogenetic relations among animals are rapidly being refined or revised in light of new data and powerful new analyses. These revelations in turn are rekindling interest in the function, development, and evolution of animals from all branches of the zoological tree. Tools and insights derived from work on a few model organisms are being applied widely to fill in significant gaps in our knowledge about how the astonishing diversity of animal characteristics evolved.Paralleling this new excitement is an upheaval in scientific publishing. Increasingly specialized journals are sprouting up worldwide as publishers rush to embrace emerging areas of excitement. Electronic communication is re-defining expectations about how new knowledge is disseminated both in format and in mode of transmission and about the time from submission to publication. For established journals to survive, they too must evolve.This journal, ZOOLOGY, is evolving to meet the needs and expectations of the modern community of animal biologists. It aims to promote research like that of it's founder J.W. Spengel — that explicitly emphasizes comparative aspects of animal biology. With the rapid growth of phylogenetic information, ZOOLOGY now offers a venue where the full impact of recent phylogenetic advances on our understanding of animal form, function, development, and evolution can be addressed. An ambitious new group of editors, a new advisory board, and a professionally staffed editorial office, are working to rejuvenate ZOOLOGY as an internationally recognized leader in comparative animal biology.ZOOLOGY has a distinguished place in the pantheon of animal biology journals. It ranks among the oldest continuously published journals in Germany. Founded in 1886 as Zoologische Jahrbücher it quickly rose to prominence among European zoological journals. In the early 1990's, after political and social upheavaling some European countries and after the reunification of Germany, the journal took a more international approach under a new title, ZOOLOGY — ANALYSIS OF COMPLEX SYSTEMS (ZACS). For the last four years, ZOOLOGY has also worked in close cooperation with the German Zoological Society and this tradition will continue. Once each year, it will publish review lectures presented at the annual meeting of the Society. A supplement to ZOOLOGY, containing the abstracts of oral and poster presentations of the annual meeting, will also be produced in conjunction with the German Zoological Society.But the new ZOOLOGY also recognizes the increasing importance of rapid and international communication in all areas of animal biology. It therefore aims to reduce publication time drastically and to enhance the speed and rigor of the review process. The new editors and editorial board are committed to maintaining the highest scientific standards and also to remaining flexible enough to adjust to the ever changing field of animal biology. Recognizing the increasing importance of rapid, effective, international communication, the new ZOOLOGY will offer:— the highest scientific standards— a short review time— a publication time schedule of three months after acceptance— color plates free of charge (at the editors' discretion)— an online version published in advance of the printed journal— free E-mail Table of Contents alerts so papers are widely publicized— papers abstracted/indexed by all the major scientific indexing servicesAs the new cover and the more accessible layout inside this issues show, the change has already begun. The future holds great promise for animal biology. Join us as Zoology strives to fulfil that promise.Spring 2001J. Matthias StarckThomas C. BoschA. Richard PalmerKiyokazu Agata     

The ultrastructure of the mid-gut cells of Nasonia vitripennis (Walker) (Hymenoptera,Pteromalidae)

Summary The ultrastructure of the mid-gut cells of female Nasonia vitripennis is described. The mid-gut consists of a uniform, single-cell epithelium. The cells of different gut regions were analysed using morphometric techniques in order to determine any differences in the components. The structure of the cells is described in the unfed animal, and after varying periods of feeding on host body-fluids. Tissues were sampled after 12 h and 24 h of feeding on host body-fluids and after 24 h feeding/24 h starvation. The cells were found to be complex and contain an organelle component that allows solute-transport and extensive lipid synthesis. A limited cytochemical analysis involving the lysosomal marker enzyme-acid phosphatase — and the respiratory enzyme — cytochrome oxidase was carried out.We are indebted to Professor E.W. Knight-Jones, in whose Department this work was carried out, and to the Science Research Council for financial support to one of us (I.D.)     

Seroepidemiology of Crimean-Congo Haemorrhagic Fever among cattle in Cameroon: Implications from a One Health perspective

BackgroundCrimean-Congo Haemorrhagic Fever (CCHF) is a tick-borne viral zoonotic disease distributed across several continents and recognized as an ongoing health threat. In humans, the infection can progress to a severe disease with high fatality, raising public health concerns due to the limited prophylactic and therapeutic options available. Animal species, clinically unaffected by the virus, serve as viral reservoirs and amplifier hosts, and can be a valuable tool for surveillance. Little is known about the occurrence and prevalence of Crimean-Congo Haemorrhagic Fever Virus (CCHFV) in Cameroon. Knowledge on CCHFV exposure and the factors associated with its presence in sentinel species are a valuable resource to better understand transmission dynamics and assess local risks for zoonotic disease emergence.Methods and findingsWe conducted a CCHFV serological survey and risk factor analysis for animal level seropositivity in pastoral and dairy cattle in the North West Region (NWR) and the Vina Division (VD) of the Adamawa Region in Cameroon. Seroprevalence estimates were adjusted for sampling design-effects and test performance. In addition, explanatory multivariable logistic regression mixed-effects models were fit to estimate the effect of animal characteristics, husbandry practices, risk contacts and ecological features on the serological status of pastoral cattle. The overall seroprevalence was 56.0% (95% CI 53.5–58.6) and 6.7% (95% CI 2.6–16.1) among pastoral and dairy cattle, respectively. Animals going on transhumance had twice the odds of being seropositive (OR 2.0, 95% CI 1.1–3.8), indicating that animal movements could be implicated in disease expansion. From an ecological perspective, absolute humidity (OR 0.6, 95% CI 0.4–0.9) and shrub density (OR 2.1, 95% CI 1.4–3.2) were associated with seropositivity, which suggests an underlying viral dynamic connecting vertebrate host and ticks in a complex transmission network.ConclusionsThis study demonstrated high seroprevalence levels of CCHFV antibodies in cattle in Cameroon indicating a potential risk to human populations. However, current understanding of the underlying dynamics of CCHFV locally and the real risk for human populations is incomplete. Further studies designed using a One Health approach are required to improve local knowledge of the disease, host interactions and environmental risk factors. This information is crucial to better project the risks for human populations located in CCHFV-suitable ecological niches.     

Attempt to modify rate and duration of licking in rats by operant conditioning

Lick-rate in rats is said to be constant for a given animal, despite variations of internal and external stimuli. On the other hand, small changes can be observed due to changes in the construction of the licking device. However, variations do not exceed 20%.In an attempt to gain operant control over the ILI (interlick interval — the time between two lick-onsets) the delivery of reinforcement (20 μl water) was made dependent on the emission of ILIs of a predetermined length longer than during baseline licking. It could be observed that rats could not shift the peak of their ILI distribution within the reinforced range but — to increase the number of reinforcements — they increased the scatter of the ILI distribution or developed a “harmonic” peak at double ILI length. When the animals were forced in a second experiment to prolong the lick-duration (time of tongue-spout contact) to obtain water, they failed if the restriction from the drinking spout made a closer approach impossible.It is argued that the ability to obtain reinforcement under both schedules is due to postural changes of the animal. The mechanisms controlling licking seem to be relatively constant, which allows good coordination with other behaviours which have to be performed during drinking, such as breathing and swallowing. It can be concluded that the amount of water consumed by rats is controlled by the length of time spent in licking and not by changing the lick-rate.     

Genetic and phenotypic variation in diet breadth in a generalist herbivore

Summary The genetic and plastic components of polyphagy were investigated in a population ofLymantria dispar, the gypsy moth. A simple genetic experiment assessed the expression of (1) genetic variability in life history traits within each of four environments, (2) genetic variability in diet breadth, expressed as a change in the ranks of family performance across hosts, and (3) homeostasis (equivalent performance by a family across hosts) versus phenotypic plasticity (variable performance by a family across hosts). Sibs from each of 14 families, randomly selected from a single population, were reared on four diets: two natural hosts — chestnut and red oak, and two synthetic hosts — a standard laboratory diet and a low-protein version of this diet. Average population performance, measured in terms of development time and pupal weight, was better on standard laboratory diet than on low-protein diet, and was equal on chestnut and red oak for pupal weight, but better on chestnut oak for development time. Average population performance provided no information about the genetic component of host use ability. The gypsy moth expressed genetic variation in development time within each host environment and in pupal weight within natural host environments. Phenotypic plasticity was expressed by a significant number of families in development time and pupal weight across synthetic hosts and, to a lesser extent, across natural hosts. It was only across natural hosts that genetic variation in diet breadth was expressed, and this was confined to females. Genetic variability in diet breadth may be maintained in this species as a consequence of the unpredictability of its food sources.     

Time Allocation Patterns of Lowland Woolly Monkeys (Lagothrix lagotricha poeppigii) in a Neotropical Terra Firma Forest

We investigated the time allocation decisions of lowland woolly monkeys (Lagothrix lagotricha poeppigii) in a terra firma forest in eastern Ecuador where they occur sympatrically with 9 other primate species. Woolly monkeys spent considerable amounts of time searching for and attempting to procure animal prey—roughly as much time as they spent consuming plant material: ripe fruits, leaves, and flowers. The amount of time spent foraging for animal prey is positively related to the habitat-wide availability of ripe fruits (the predominant component of the woolly monkey diet), and negatively related to both ambient temperature and the abundance of potential prey items in the habitat. Time spent resting showed exactly the opposite pattern with respect to these ecological variables. These results suggest that woolly monkeys follow an energy-maximizing strategy of food acquisition during times of fruit abundance—focusing on animal foods and perhaps laying down fat reserves to utilize when ecological conditions worsen—and follow an energy-minimizing strategy when fruit resources are scarce. Such a strong and seasonal commitment to animal prey foraging is unique among the ateline primates and is not ubiquitous even among lowland woolly monkeys. We suggest that this foraging strategy, and the greater intragroup cohesion that characterizes some populations of Lagothrix, are both opportunistic responses to regional differences in habitat quality. Identifying and accounting for such intraspecific variation should be a goal of any analysis of comparative socioecology.     

Biological pacemaker created by fetal cardiomyocyte transplantation

Summary Background—The aim of this study was to investigate the feasibility of an alternative approach to electronic pacemaker by using spontaneously excitable cell grafts as a biological pacemaker in a large animal model of complete atrioventricular block. Methods and Results—Dissociated male human atrial cardiomyocytes including sinus nodal cells were grafted into the free wall of the left ventricle in five female pigs. Three weeks after the injection of cell-grafted solution/control medium the pigs underwent catheter ablation of the atrioventricular node (AV-node). After complete AV block was created, the idioventricular beat rate was more rapid in cell-grafted pigs than that in control pigs (86±21 vs. 30±10 bpm; P<0.001). Administering of isoprenalin significantly increased idioventricular rate from 86±21 to 117±18 bpm in the cell-grafted animals (P<0.01). Electrophysiological mapping studies demonstrated that the idioventricular rhythm originated from the cell-injection site. Polymerase chain reaction verifying the existence of SRY DNA in the cell injection site indicated that the grafted male cells were survived. Furthermore, the connexin-43 and N-cadherin positive junctions between donor cardiomyocytes and host cells were identified. Conclusion—Xenografted fetal human atrial cardiomyocytes are able to survive and integrate into the host myocardium, and show a pacing function that can be modulated by autonomic agents.This work was supported by grants from Natural Science Foundation of China, Scientific Research Foundation of Hubei Province, Scientific and Technological Program of Wuhan City.     

Tracking facilitates 3-D motion estimation

The recently emerging paradigm of Active Vision advocates studying visual problems in form of modules that are directly related to a visual task for observers that are active. Along these lines, we are arguing that in many cases when an object is moving in an unrestricted manner (translation and rotation) in the 3D world, we are just interested in the motion's translational components. For a monocular observer, using only the normal flow — the spatio-temporal derivatives of the image intensity function — we solve the problem of computing the direction of translation and the time to collision. We do not use optical flow since its computation is an ill-posed problem, and in the general case it is not the same as the motion field — the projection of 3D motion on the image plane. The basic idea of our motion parameter estimation strategy lies in the employment of fixation and tracking. Fixation simplifies much of the computation by placing the object at the center of the visual field, and the main advantage of tracking is the accumulation of information over time. We show how tracking is accomplished using normal flow measurements and use it for two different tasks in the solution process. First it serves as a tool to compensate for the lack of existence of an optical flow field and thus to estimate the translation parallel to the image plane; and second it gathers information about the motion component perpendicular to the image plane.     

Informing the Historical Record of Experimental Nonhuman Primate Infections with Ebola Virus: Genomic Characterization of USAMRIID Ebola Virus/H.sapiens-tc/COD/1995/Kikwit-9510621 Challenge Stock “R4368” and Its Replacement “R4415”

The creation of licensed medical countermeasures against Select Agents such as Ebola virus (EBOV) is critically dependent on the use of standardized reagents, assays, and animal models. We performed full genome reconstruction, population genomics, contaminant analysis, and characterization of the glycoprotein gene editing site of historical United States Army Medical Research Institute of Infectious Diseases (USAMRIID) nonhuman-primate challenge stock Ebola virus Kikwit “R4368” and its 2014 replacement “R4415.” We also provide characterization of the master stock used to create “R4415.” The obtained data are essential to understanding the quality of the seed stock reagents used in pivotal animal studies that have been used to inform medical countermeasure development. Furthermore, these data might add to the understanding of the influence of EBOV variant populations on pathogenesis and disease outcome and inform attempts to avoid the evolution of EBOV escape mutants in response to current therapeutics. Finally, as the primary challenge stocks have changed over time, these data will provide a baseline for understanding and correlating past and future animal study results.     

Characteristics of oviposition behaviour of the pollen beetle, Meligethes aeneus on four different host plants

Oviposition behaviour of Meligethes aeneus F. (Coleoptera: Nitidulidae) is characterised and quantified on four different plant species. Six behavioural components are identified: W—walking, WA—walking with abdomen on surface, R—resting, B—biting, AOH—placing abdomen over the bite hole and OVI—oviposition. Comparison of host acceptance behaviours on Brassica napus L., Brassica juncea (L.) Czern, Brassica nigra (L.) Koch and Sinapis alba L. showed that S. alba was accepted as a host only after a long exposure to the plant. Behaviour on the Brassica species was similar, however on B. nigra beetles spent a high proportion of time actually ovipositing. We conclude that important cues for oviposition are located both on the bud surface and inside the bud.     

Statistical properties of polymorphism in host—parasite genetics

Summary Host—parasite interactions often have complex dynamics. At the level of individual allele frequencies, the dynamics are difficult to predict and difficult to measure. However, aggregate properties of polymorphism, such as allelic diversity or the frequency of resistance, may be relatively easy to work with. I study this problem with computer simulations of a host—parasite model. In one example, the simulations show that the allelic diversity at a locus is similar in a host—parasite model and a neutral model in which drift is the only evolutionary process. Allelic diversity is similar in the two models, even though the temporal dynamics of individual allele frequencies are very different. In a second example, the genetic system that would be inferred from analysing samples of hosts and parasites is quite different from the actual specificity that determines the dynamics of the system. Thus, general conclusions about the specificity of host—parasite genetics must be analysed in the context of the expected statistical distributions of polymorphism. The final example shows that the frequency of resistance provides an interesting aggregate measure of host—parasite polymorphism. If the ratio of parasite generation time to the time between the reproductive seasons of the hosts is small, then no regular periodicity in the frequency of resistance occurs. However, if parasites have many generations per reproductive season of the host, then resistance fluctuates with a period equal to the seasonality of the host. The important role of seasonality shown here differs from the emphasis in previous theories on the relative generation times of host and parasite.     

Immunogenetic polymorphism of lipoproteins in swine

Five new antigenic markers (allotypes) of swine serum lipoproteins are described. Specific antiallotype reagents were obtained from alloimmune precipitating sera. Identification studies and genetic analysis indicate that the five serum alloantigens—designated Lpp6, Lpp11, Lpp12, Lpp13, and Lpp14—are markers of low-density lipoproteins (LDL),d 1.002–1.075 g/ml, and are members of a previously described Lpp system. The Lpp6 allotype belongs to the group of individual markers and is determined by a new codominant allelic gene,Lpp ⁶, whereas the remaining four antigens—Lpp11, Lpp12, Lpp13, and Lpp 14—named common specificities, behave as alternative variants to Lpp1, Lpp2, Lpp3, and Lpp4, respectively, forming pairs of mutually exclusive alloantigens. Each Lpp gene in a heterozygous animal expresses itself independently on separate molecules and each haplotype carries one individual and at least four common specificities. The relationship between common and individual specificities, together with their number in the complex haplotypes, seems to shed some light on evolution of Lpp genes. It is proposed in this concept that the original gene for low-density lipoproteins in swine, and also in rhesus monkeys and the human, consisted of genetic information for common specificities only, the individual specificities evolving later as a result of point mutations.     

Host characteristics and infection level of an intestinal parasite Corynosoma strumosum (Acanthocephala) in the Kuril harbor seal of Erimo Cape,Hokkaido, Japan

The Kuril harbor seal around Hokkaido is presently recovering from a resource crisis while conflicts with local fisheries have become a concern. However, its feeding habits, which are fundamental information for taking proper preventive measures, are still poorly understood. We thus examined the infection status of a trophically-transmitted parasite, Corynosoma strumosum in the seals of Erimo Cape, to assess the host's feeding habits with a practical view of the parasite as a biological indicator. A total of 2802 worms were found from 20 male and 20 female by-caught animals in salmon set nets within local fisheries during August to November 2014. The parasite abundance was explained mainly by the host's developmental stage and intestinal length while weakly affected by gender and body size, through an estimation of generalized linear models combined with hierarchical partitioning. Considering the past records that demersal fishes are the probable main sources of infection, the infection level may owe to individual host differences regarding these sources and/or feeding grounds with relating the host characteristics. This supports that the resource management of Kuril harbor seals requires careful consideration of the individual differences in feeding behavior.     

Associative recognition and storage in a model network of physiological neurons

We consider a neural network model in which the single neurons are chosen to closely resemble known physiological properties. The neurons are assumed to be linked by synapses which change their strength according to Hebbian rules on a short time scale (100ms). The dynamics of the network — the time evolution of the cell potentials and the synapses — is investigated by computer simulation. As in more abstract network models (Cooper 1973; Hopfield 1982; Kohonen 1984) it is found that the local dynamics of the cell potentials and the synaptic strengths result in global cooperative properties of the network and enable the network to process an incoming flux of information and to learn and store patterns associatively. A trained net can associate missing details of a pattern, can correct wrong details and can suppress noise in a pattern. The network can further abstract the prototype from a series of patterns with variations. A suitable coupling constant connecting the dynamics of the cell potentials with the synaptic strengths is derived by a mean field approximation. This coupling constant controls the neural sensitivity and thereby avoids both extremes of the network state, the state of permanent inactivity and the state of epileptic hyperactivity.     

The influence of parasitic water mites on the instantaneous death rate of their hosts

Summary The effect of 2 species of water mites on the instantaneous death rate of their hosts was measured on the basis of laboratory experiments. In both parasite-host association — the parasitic water mite Hydryphantes tenuabilis on the aquatic insect host Hydrometra australis and the parasitic water mite Arrenurus pseudotenuicollis on the mosquito Anopheles crucians — the effect of mite load on the instantaneous death rate of the host appeared to be linear. Also, the impact of a single parasite on the host's death rate was apparently related to the ratio of parasite to host body weight. The results of this study are in general agreement with recent theoretical investigations of the regulation of host populations by parasites.     

DNA sequence organization in the genome of Petroselinum sativum (Umbelliferae)

The genome of parsley was studied by DNA/DNA reassociation to reveal its spectrum of DNA reiteration frequencies and sequence organization. The reassociation of 300 nucleotide DNA fragments indicates the presence of four classes of DNA differing in repetition frequency. These classes are: highly repetitive sequences, fast intermediate repetitive sequences, slow intermediate repetitive sequences, and unique sequences. The repeated classes are reiterated on average 136,000, 3000, and 42 times respectively. A minor part of the genome is made up of palindromes. — The organization of DNA sequences in the P. sativum genome was determined by the reassociation kinetics of DNA fragments of varying length. Further information was derived from S1 nuclease resistance and from hyperchromicity measurements on DNA fragments reassociated to defined C₀t values. — The portion of the genome organized in a short period interspersion pattern amounts to 47%, with the unique sequences on an average 1000 nucleotides long, and most of the repetitive sequences about 300 nucleotides in length, whereas the weight average length may be up to 600 nucleotides. — About 5% unique DNA and 11% slow intermediate repetitive DNA consist of sequences from 10³ up to 10⁴ nucleotides long; these are interspersed with repetitive sequences of unknown length. Long repetitive sequences constitute 33% of the genome, 13% are satellite-like organized, and 20% in long stretches of intermediate repetitive DNA in which highly divergent sequences alternate with sequences that show only minimal divergence. — The results presented indicate remarkable similarities with the genomes of most animal species on which information is available. The most intriguing pecularity of the plant genome derives from its high content of repetitive DNA and the presumed organization of the latter.     

Second positive phototropic response patterns of the oat coleoptile

Summary 1.During second positive irradiation, bending increases steadily with time. Under optimal conditions, the lag between onset of illumination and beginning of parabolic bending behavior is about 3 min. — 2. Shortly after irradiation ceases, bending becomes linear with time. On a clinostat, bending continues for about 2.5 hr. Auxanometric measurements show that the ultimate cessation of bending is not due to failing growth rate. — 3. The second positive response shows a striking dependence on intensity of irradiation. Inactivation occurs when irradiation approaches the intensity of full daylight. — 4. Induction is linear with duration of illumination, both at purely activating intensities and at partially inactivating intensities. — 5. Induction at 2°, while somewhat slower than at 25°, retains linear dependence on exposure duration. This suggests that the reactions immediately following light reception are slowed but not stopped at low temperature. — 6. Growth, which drops to about 0.5 /min at 2°, resumes at about 18 min^-1 as soon as plants are warmed to 25°. Curvature does not seem to begin for about 10 min. Combined with information about lag time for primary auxin action, this suggests that lateral auxin transport, as well as growth, is strongly inhibited at near-freezing temperatures. — 7. The induced transport system is highly stable at 2°. — 8. Under optimal conditions, the lag between onset of irradiation and induction of capacity to produce measurable curvature is only a few seconds. The length of the lag is dependent on the rate of induction. The lag is thought to be due to the requirement that enough induction be accumulated to overcome resistance of the coleoptile. — 9. Induction is dependent on the gradient of light across the coleoptile, whether measured for purely activating or partially inactivating intensities. The light received is probably integrated either across individual cells or across the entire width of the coleoptile.     

Effects of air ions on germination ofHelminthosporium teres

Effects of host — pathogen interactions with respect to relatively high concentrations of artificially produced air ions were studied in the laboratory. Continuous and long exposures ofHelminthosporium teres in the culture medium and under controlled conditions to positive air ions, produced a time — delay of about 6 hours on spore germination. Negative ions produced no such effect. Temporary structural abnormalities of the germ tubes were observed for two to three hours when exposed to either positive or negative air ions. Sprayed inoculum of spores on actual leaf surfaces of barley plants, exposed to positive ions, suppressed germination for a considerably longer time than those observed in the culture medium.     

Shifting white pox aetiologies affecting Acropora palmata in the Florida Keys, 1994–2014

We propose ‘the moving target hypothesis’ to describe the aetiology of a contemporary coral disease that differs from that of its historical disease state. Hitting the target with coral disease aetiology is a complex pursuit that requires understanding of host and environment, and may lack a single pathogen solution. White pox disease (WPX) affects the Caribbean coral Acropora palmata. Acroporid serratiosis is a form of WPX for which the bacterial pathogen (Serratia marcescens) has been established. We used long-term (1994–2014) photographic monitoring to evaluate historical and contemporary epizootiology and aetiology of WPX affecting A. palmata at eight reefs in the Florida Keys. Ranges of WPX prevalence over time (0–71.4%) were comparable for the duration of the 20-year study. Whole colony mortality and disease severity were high in historical (1994–2004), and low in contemporary (2008–2014), outbreaks of WPX. Acroporid serratiosis was diagnosed for some historical (1999, 2003) and contemporary (2012, 2013) outbreaks, but this form of WPX was not confirmed for all WPX cases. Our results serve as a context for considering aetiology as a moving target for WPX and other coral diseases for which pathogens are established and/or candidate pathogens are identified. Coral aetiology investigations completed to date suggest that changes in pathogen, host and/or environment alter the disease state and complicate diagnosis.     

A possible contribution of phenomenology to ethology: Application to a behaviour pattern in the mouse

Classical ethology encourages a causal approach to animal behaviour, using Tinbergen's four questions concerning evolution, function, mechanism and development of behaviour. It sets aside the study of mental processes, which could otherwise help to unify our picture of the relationships between animal and environment. Here the steps in research focused on the psychological meaning of a peculiar behaviour in the mouse — carrying its tail — and what this implies regarding the mouse's cognitive world are given. Initial empirical observations suggested epistemic choices concerning space and object notions in the mouse; this led us to go beyond the first stage in exploring the significance of this behaviour. Later experiments showed the limitations of an explanation based on a cause-effect relationship. An interpretative model integrating a phenomenological conceptual framework is proposed.