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Full-Text Articles in Life Sciences
Size Matters: A Test Of Boldness In Eight Populations Of The Poeciliid Brachyraphis Episcopi, Culum Brown, Victoria Braithwaite
Size Matters: A Test Of Boldness In Eight Populations Of The Poeciliid Brachyraphis Episcopi, Culum Brown, Victoria Braithwaite
Sentience Collection
Individual variation in behaviour within populations may be explained in part by demographics and long-term, stable individual psychological differences. We examined the relation between boldness (taken as the time to emerge from a shelter and explore a novel environment) and body size in eight populations of the poeciliid Brachyraphis episcopi originating from sites upstream and downstream of waterfalls in four rivers that run into the Panama Canal. The relation between body size and time to emerge from a shelter was positive, with larger fish taking longer to emerge. This relation differed between downstream and upstream sites, being significant in the …
Origin And Evolution Of Large Brains In Toothed Whales, Lori Marino, Daniel W. Mcshea, Mark D. Uhen
Origin And Evolution Of Large Brains In Toothed Whales, Lori Marino, Daniel W. Mcshea, Mark D. Uhen
Veterinary Science and Medicine Collection
Toothed whales (order Cetacea: suborder Odontoceti) are highly encephalized, possessing brains that are significantly larger than expected for their body sizes. In particular, the odontocete superfamily Delphinoidea (dolphins, porpoises, belugas, and narwhals) comprises numerous species with encephalization levels second only to modern humans and greater than all other mammals. Odontocetes have also demonstrated behavioral faculties previously only ascribed to humans and, to some extent, other great apes. How did the large brains of odontocetes evolve? To begin to investigate this question, we quantified and averaged estimates of brain and body size for 36 fossil cetacean species using computed tomography and …
Evolution Of Nociception In Vertebrates: Comparative Analysis Of Lower Vertebrates, Lynne U. Sneddon
Evolution Of Nociception In Vertebrates: Comparative Analysis Of Lower Vertebrates, Lynne U. Sneddon
Veterinary Science and Medicine Collection
Nociception is an important sensory system of major fundamental and clinical relevance. The nociceptive system of higher vertebrates is well studied with a wealth of information about nociceptor properties, involvement of the central nervous system and the in vivo responses to a noxious experience are already characterised. However, relatively little is known about nociception in lower vertebrates and this review brings together a variety of studies to understand how this information can inform the evolution of nociception in vertebrates. It has been demonstrated that teleost fish possess nociceptors innervated by the trigeminal nerve and that these are physiologically similar to …
Free-Stall Dimensions: Effects On Preference And Stall Usage, Cassandra B. Tucker, Daniel M. Weary, David Fraser
Free-Stall Dimensions: Effects On Preference And Stall Usage, Cassandra B. Tucker, Daniel M. Weary, David Fraser
Housing and Confinement of Farm Animals Collection
In 2 experiments, free-stall dimensions were examined to determine how they affected stall preference, usage, cleanliness, and milk production in Holstein dairy cattle. In experiment 1, stall width (112 or 132 cm) and stall length (229 and 274 cm from curb to wall) were compared in a 2 × 2 factorial arrangement of stall treatments using 15 individually housed, non-lactating animals. Cows showed no clear preference for stall size as measured by lying time. When animals had no choice between stalls, average lying time was higher in the wide stalls than in the narrow stalls (10.8 vs. 9.6 ± 0.3 …
Reflections On Animal Selves, Marc Bekoff, Paul W. Sherman
Reflections On Animal Selves, Marc Bekoff, Paul W. Sherman
Sentience Collection
Is self-cognizance a uniquely human attribute, or do other animals also have a sense of self? Although there is considerable interest in this question, answers remain elusive. Progress has been stymied by misunderstandings in terminology, a focus on a narrow range of species, and controversies over key concepts, experimental paradigms and interpretations of data. Here, we propose a new conceptual and terminological framework, emphasizing that degrees of self-cognizance differ among animals because of the cognitive demands that their species-specific social structures and life-history characteristics have placed upon them over evolutionary time. We suggest that the self-cognizance of an organism falls …
Differences In Response To Hypoxia In The Three-Spined Stickleback From Lotic And Lentic Localities: Dominance And An Anaerobic Metabolite, L. U. Sneddon, J. Yerbury
Differences In Response To Hypoxia In The Three-Spined Stickleback From Lotic And Lentic Localities: Dominance And An Anaerobic Metabolite, L. U. Sneddon, J. Yerbury
Aquaculture Collection
Dominance hierarchies of the three-spined stickleback Gasterosteus aculeatus from river and pond populations were subjected to hypoxia (20%, range±1%). Under hypoxia, the hierarchies were less stable in terms of rank position and tissue L-lactate was higher in river fish than pond fish under normoxia and hypoxia. Dominant fish gained mass under normoxia but lost mass under hypoxic conditions possibly due to them maintaining high levels of aggression.