Observations of scent-marking and discriminating self from others by a domestic dog (Canis familiaris): tales of displaced yellow snow.

Little is known about what stimuli trigger urinating or scent-marking in domestic dogs, Canis familiaris, or their wild relatives. While it is often suggested that the urine of other animals influences urinating and scent-marking patterns in canids, this has not been verified experimentally. To investigate the role of urine in eliciting urinating and marking, in this pilot study I moved urine-saturated snow ('yellow snow') from place-to-place during five winters to compare the responses of an adult male domestic dog, Jethro, to his own and others' urine. Jethro spent less time sniffing his own urine than that of other males or females, and that while his interest in his own urine waned with time it remained relatively constant for other individuals' urine. Jethro infrequently urinated over or sniffed and then immediately urinated over (scent-marked) his own urine. He marked over the urine of other males more frequently than he marked over females' urine. The method used here can be extended to other species for which experimental data are lacking. Though based on one dog, these novel data may further our knowledge of the role of scent-marking in territorial behavior and of sex differences in territory acquisition and maintenance.

Mammalian play: training for the unexpected.

In this review, we present a new conceptual framework for the study of play behavior, a hitherto puzzling array of seemingly purposeless and unrelated behavioral elements that are recognizable as play throughout the mammalian lineage. Our major new functional hypothesis is that play enables animals to develop flexible kinematic and emotional responses to unexpected events in which they experience a sudden loss of control. Specifically, we propose that play functions to increase the versatility of movements used to recover from sudden shocks such as loss of balance and falling over, and to enhance the ability of animals to cope emotionally with unexpected stressful situations. To obtain this "training for the unexpected," we suggest that animals actively seek and create unexpected situations in play through self-handicapping; that is, deliberately relaxing control over their movements or actively putting themselves into disadvantageous positions and situations. Thus, play is comprised of sequences in which the players switch rapidly between well-controlled movements similar to those used in "serious" behavior and self-handicapping movements that result in temporary loss of control. We propose that this playful switching between in-control and out-of-control elements is cognitively demanding, setting phylogenetic and ontogenetic constraints on play, and is underlain by neuroendocrinological responses that produce a complex emotional state known as "having fun." Furthermore, we propose that play is often prompted by relatively novel or unpredictable stimuli, and is thus related to, although distinct from, exploration. We present 24 predictions that arise from our new theoretical framework, examining the extent to which they are supported by the existing empirical evidence and contrasting them with the predictions of four major alternative hypotheses about play. We argue that our "training for the unexpected" hypothesis can account for some previously puzzling kinematic, structural, motivational, emotional, cognitive, social, ontogenetic, and phylogenetic aspects of play. It may also account for a diversity of individual methods for coping with unexpected misfortunes.

Predicting flock vigilance from simple passerine interactions: modelling with cellular automata.

Vigilance in flocks can be described and modelled as a plausible set of local interactions between neighbouring birds. Each bird in the modelled flock chooses to feed or to scan based solely on whether or not its neighbours are feeding or scanning. This simple model has the ability both to reproduce observations that have not been previously explained and to predict flock behaviours that might be confirmed with future field studies. Examples include simulations showing decreased vigilance with increased flock size (as observed in the field), greater time spent scanning when obstacles such as trees are present (as observed) and a coordinated feed/scan pattern (that is predicted to become increasingly coordinated when the birds look up from feeding more frequently). The numerical model also predicts that flock geometry influences vigilance. If two flocks are the same size, individuals in the one with the larger perimeter will spend more time scanning. This prediction could be tested with field studies and already has been observed empirically for two limiting cases: birds arranged in a line (high perimeters, high scan times) and birds in a circle (lower perimeters, lower scan times). As demonstrated by its multiple successes, cellular models of this type are a powerful new approach to understanding bird flock behaviours. Copyright 1999 The Association for the Study of Animal Behaviour.

Teleology, function, design and the evolution of animal behaviour.

Concerns about teleological language in evolutionary biology focus on the notions of function, design and adaptation. Accounts that naturalize these ideas are currently popular. In keeping with recent developments in evolutionary theory and philosophy of biology, three naturalistic analyses of function - current utility, historical function, and functions as capacities - should be differentiated. All have roles to play in biology, although the historical conception seems the most central to evolutionary theory. While rarely distinguished from function, design should be regarded as an extension of historical function. We consider the utility of this distinction for the study of behaviour.

Cognitive ethology, vigilance, information gathering, and representation: Who might know what and why?

Cognitive ethology, a relatively new interdisciplinary and integrative science, is under attack with respect to its scientific status. However, there also are strong supporters of research in this area. In this paper I consider My study of vigilance indicates that the way in which individuals are positioned with respect to one another influences their behavior, and that when a flock contains four or more birds there are large changes in scanning and other patterns of behavior that may be related to how grosbeaks attempt to gather information about other flock members. When birds are arranged in a circular array so that they can see one another easily compared to when they are arranged in a line that makes visual monitoring of flock members more difficult, birds who have difficulty seeing one another are These differences in behavior argue against the pooling of data collected on individuals feeding in different geometric arrays. The variations in behavior also may say something about if and how individuals attempt visually to represent their group to themselves-how they form, store, and use records of the behavior of others to inform their own future behavior.

Cognitive ethology and applied philosophy: The significance of an evolutionary biology of mind.

The broad field of cognitive ethology, in which internal mental states are inferred from the behavior they explain, is receiving increased attention nowadays from diverse scientists and philosophers. The nature of the results and how they are presented greatly influence how humans assess their place in the natural world and how they view other animals. The attribution of consciousness and intelligence to other animals suggests that they have moral rights. The results of comparative cognitive ethological analyses and how they are presented may play a large role in defining the domain of morally permissible research, and in the development of research strategies including decisions on feeding and housing, treatment, handling, and what happens to animal subjects when the research is completed. Scientists and philosophers interested in the evolution of behavior and mental continuity can have a significant impact on how others view the world.

Relative contribution of "determinant selection" and "holes in the T-cell repertoire" to T-cell responses.

Using BALB/c and CBA/J mice, the I-region associated (Ia) binding capacity and T-cell immunogenicity of a panel of 14 overlapping peptides that span the entire sequence of the protein staphylococcal nuclease (Nase) was examined to evaluate major histocompatibility gene complex (MHC) control of T-cell responses. Ia binding and Ia-restricted T-cell immunogenicity could be determined for a total of 54 peptide-MHC combinations. Only 30% of the 54 instances examined involved detectable Ia binding, but they represented almost all (12 of 13) of the immune responses found. However, binding to Ia was not sufficient to ensure T-cell immunogenicity, since only 70% of the binding events were productive--i.e., were associated with an immune response. Thus, Ia molecules have the expected characteristics of a highly permissive capacity for antigen interaction that allows them to function as restriction elements for a large universe of antigens. On the other hand, since the Ia molecules cannot distinguish between self and non-self, not all antigen-Ia interactions would be permitted to elicit a T-cell response. It appears that both Ia binding ("determinant selection") and T-cell repertoire act in concert to define the immune response status of an individual toward any particular T-cell epitope.

Feralization: The making of wild domestic animals.

The widely accepted viewpoint that feralization is the reverse of domestication requires that the feralization process be restricted to populations of animals and, therefore, cannot occur in individuals. An alternative, ontogenetic approach is presented in which feralization is defined as the process by which individual domestic animals either become desocialized from humans, or never become socialized, and thus behave as untamed, non-domestic animals. Feralization will vary among species and, intraspecifically, will depend upon an individual's age and history of socialization to humans. Because feralization is not equated with morphological change resulting from evolutionary processes, species formation is not an accurate indicator of feral condition.

Motor training and physical fitness: possible short- and long-term influences on the development of individual differences in behavior.

Individual differences in the behavior of young and adult animals have been documented in diverse species. Possible sources of such variation are of interest to scientists representing many disciplines, including behavior, genetics, and population and evolutionary biology. Two variables that may be important in the ontogeny and maintenance of behavioral differences are (1) individual physical (aerobic and anaerobic) fitness and (2) possible genetic variations underlying individual abilities to engage in, and to benefit from, motor training early in life. The differential development of aerobic and anaerobic capacities may play a significant role in the ontogeny of individual differences in the performance of various motor skills. There also may be short- and long-term consequences of variations in physical fitness that influence individual abilities to perform energy demanding acts during aggressive encounters, interactions with prey or predators, and courtship and breeding. Genetic studies of a limited number of species indicate that specific genotypes are correlated with individual variations in motor performance, even among conspecifics. Multidisciplinary research concerning possible relationships among the ontogeny of physical fitness, genetics, and variations in behavior is needed. Recent work on the relationship between individual differences in physical fitness and variations in the behavior of adult cold-blooded vertebrates provides a good model for comparative research on warm-blooded species.

Studies on the mechanism of stimulation of T cells by the Mycoplasma arthritidis-derived mitogen. Role of class II IE molecules.

A mitogen derived from the supernatant of broth cultures of Mycoplasma arthritidis (MAS-P) stimulates a proliferative response by normal, unprimed T cells and interleukin 2 production by some, but not all, T cell hybridomas. The response requires an IE-positive accessory cell (AC). The direct participation of IE, and not IA, in this system was confirmed by two sets of experiments. First, L cells transfected with IE, but not IA, provided effective AC function for both normal T cells and the T cell hybridoma DO-11.10. Second, we have taken a more direct approach by showing that purified IE incorporated in liposomes and used to coat glass beads can support the MAS-P response of the DO-11.10 T cell hybridoma in the absence of intact AC or other AC molecules. Although the receptor for IE-MAS-P has not been identified, we have eliminated from consideration two potential T cell recognition structures. Monoclonal antibody to the antigen-major histocompatibility complex specific receptor failed to inhibit the MAS-P response of DO-11.10 or the T cell line LBRM-33. Furthermore, the L3T4 molecule did not appear to be involved since an L3T4-negative variant of DO-11.10 responded well to the mitogen. In addition, we show that both Lyt-2-positive and L3T4-positive T cells respond to this class II-restricted stimulus. Thus, we postulate the existence of a non-T cell receptor, non-L3T4 receptor that recognizes MAS-P in association with a presumed nonpolymorphic region of IE.

Activation requirements for normal T cells: accessory cell-dependent and -independent stimulation by anti-receptor antibodies.

We have examined the requirements for the activation of normal T cells by two anti-T cell receptor antibody preparations, including a rabbit antiserum, R3497, which binds to all normal T cells, and a rat monoclonal antibody, KJ16-133, which binds to about 20% of T cells. The requirements for stimulation of T cells by both antibodies were similar. Soluble antibodies in the absence of accessory cells (AC) failed to induce either proliferation or the expression of IL 2 receptors, and the addition of either IL 2 or PMA failed to synergize with these soluble antibodies for an AC-independent proliferative response. Activation could only be achieved in the presence of Fc receptor-positive AC, although Fc receptor expression alone appeared not to be sufficient for AC activity because some Fc receptor-positive cells did not function in this capacity. Activation with anti-receptor antibody conjugated to Sepharose 4B beads could be demonstrated in the presence of some exogenous cofactors, such as IL 2 and PMA, but not in the presence of recombinant IL 1. When activation by soluble antibody plus AC was compared to activation by bead-conjugated antibody + recombinant IL 2, it was found that the former favored the stimulation of Lyt-2+ cells. The effects of the addition of anti-L3T4 monoclonal antibody was also examined in this system. Anti-L3T4 inhibited the response of L3T4+ cells when used in the presence of Ia+ as well as Ia- AC, and it also inhibited activation in a system in which KJ16-133 conjugated to Sepharose was used in the absence of AC. Because anti-L3T4 had an inhibitory effect in the presence of Ia- AC as well as in the absence of any AC, it is concluded that L3T4 does not necessarily function by interacting with Ia on the surface of AC, and may directly transmit down-regulatory signals when bound by anti-L3T4.

Accessory cell function in the Con A response: role of Ia-positive and Ia-negative accessory cells.

We have examined the role of Ia-positive and Ia-negative accessory cells (AC) and soluble factors in Con A-stimulated murine T cell activation. Supernatant fluids containing interleukin 1 (IL 1) derived from the P388D1 macrophage cell line and from a lipopolysaccharide (LPS)-stimulated macrophage hybridoma provided only partial reconstitution of the response of purified T cells (18 to 27%). The complete reconstitution obtained with gamma-irradiated spleen cells or LPS-activated B cells was inhibited by approximately 60 to 77% when anti-Ia antibody was included in the culture. Despite this apparent involvement of Ia+ spleen AC, Ia-negative L cell AC could also reconstitute the response of both Class I-restricted Lyt-2+ T cells and Class II-restricted L3T4+ T cells. When the Ia-negative AC were employed, the L3T4 antigen on L3T4+ T cells played a critical role because addition of anti-L3T4 antibody to the culture inhibited the response by 85 to 90%. In contrast, anti-L3T4 did not inhibit the response in the presence of spleen AC. These results suggest that the molecules involved in T cell-AC interactions may vary depending on the AC source. Moreover, at least one of the putative target ligands for L3T4 presumably is not Ia, because anti-L3T4 inhibited T cell stimulation when Ia-negative AC were used.

T cell and IR gene regulation of expression of a cross-reactive idiotype.

The immune response to the chemically defined DNP-oligo-L-lysine antigens is under Ir gene control in the guinea pig. Strain 2 (responder) guinea pigs mount a highly specific T cell-mediated and humoral immune response capable of discriminating closely related DNP-peptides. In contrast, strain 13 (nonresponder) animals fail to mount a cell-mediated response, and produce antibody that is only DNP-specific. In these studies a common idiotypic determinant is defined on highly specific anti-epsilon,DNP-Lys10 antibody produced by strain 2 guinea pigs. Ir gene nonresponder antibody is idiotype-negative. The presence of the idiotypic determinant distinguishes responder anti-epsilon,DNP-Lys10 antibody from responder antibodies elicited by structurally related antigens such as epsilon,DNP-Lys9 and alpha,DNP-Lys10-. Investigation of the regulation of idiotype expression demonstrated that production of idiotype-positive antibody requires the presence of viable, antigen-responsive T cells. Moreover, genetic analysis revealed that expression of the shared idiotype correlates directly with the phenotypic expression of I region genes (DTH responsiveness, Ia antigens) in (2 x 13)F1 x 13 backcross and randomly bred Hartley guinea pigs. Thus, Ir gene regulation of the immune response may be reflected in the v region specificities expressed by antigen-specific B cell clones.

Characterization of growth factors in human cartilage.

Growth factor activity has been identified in the chondrocytes and extracellular matrix (ECM) fractions of human costal cartilage. There was about five times more growth factor activity in the ECM than was found to be associated with the chondrocytes. The growth factor activity in chondrocytes was found to be associated with chromatin. Both the chromatin-associated growth factor (CAGF) activity and extracellular matrix growth factor (EMGF) activity were characterized for molecular weight, charge, and the effect of reduction by sulfhydryl reducing reagents. Biorex cation exchange chromatography showed that both CAGF and EMGF were cationic. CAGF and EMGF have molecular weights between 15,000 and 18,000 as determined by size exclusion chromatography on HPLC TSK 3000 columns equilibrated with guanidine-HCl and dithiothreitol.

The variability of some motor components of social play and agonistic behaviour in infant eastern coyotes, Canis latrans var.

The duration and stereotypy (in terms of duration) of three actions, stand-overs (SO), generalbites (GB), And scruff-bites (SB), were measured during social play and agonistic interactions in infant eastern coyotes (Canis latrans). The rate of biting was also calculated. We found: (1) SO's and GB's lasted a significantly shorter time during play; (2) when performed during playful interactions, all three acts showed more stereotypy; (3) there was no significant difference between the rates of occurrence of biting during the two situations. A discussion of the 'exaggerated' nature of play behaviour is presented, particularly concerning the form of motor actions that are used during this activity.

Social communication in canids: evidence for the evolution of a stereotyped Mammalian display.

The variability in the duration and form of the canid play bow was studied in infant coyotes, wolves, wolf-dog hybrids, beagles, and adult free-ranging dogs. Both duration and form showed marked stereotypy. It appears that the role of this context-specific social signal in the communication of play intention has been fostered by selection for "morphological" stereotypy.