Evolution Commons^™

Life History Of The Coastal Tailed Frog (Ascaphus Truei) Across An Elevational Gradient, Adrian Daniel Macedo

Cal Poly Humboldt theses and projects

The life history of a species is described in terms of its growth, longevity, and reproduction. Unsurprisingly, life history traits are known to vary in many taxa across environmental gradients. In the case of amphibians, species at high elevations and latitudes tend to have shorter breeding seasons, shorter activity periods, longer larval periods, reach sexual maturity at older ages, and produce fewer and larger clutches per year.

The Coastal Tailed Frog (Ascaphus truei) is an ideal species for the study of geographic variation in life history because it ranges across most of the Pacific Northwest from northern California …

On Neglected Taxa: Protostomes And The Evolution Of Myelination, Michaella P. Andrade, Charles Morphy D. Santos

Animal Sentience

Understanding the evolution of nervous and sensory systems in animals is key to understanding the distribution of animal sentience. However, the use of model organisms – mostly vertebrates, and especially mammals – often biases comparative analyses. Sneddon et al. (2018a,b) point out that using nonhuman animals as models helps us better understand the multifaceted aspects of animal pain and sentience. Several concerns need to be considered in dealing with model organisms. Here we discuss how models that are unrepresentative phylogenetically influence hypotheses about the evolution of the myelination in animals. Greater effort is needed to escape “vertebrate-centrism” in evolutionary research.

Intelligence, Complexity, And Individuality In Sheep, Lori Marino, Debra Merskin

Animal Sentience

Domestic sheep (Ovis aries) are among the earliest animals domesticated for human use. They are consumed worldwide as mutton, hogget, and lamb, kept as wool and milk producers, and used extensively in scientific research. The popular stereotype is that sheep are docile, passive, unintelligent, and timid, but a review of the research on their behavior, affect, cognition, and personality reveals that they are complex, individualistic, and social.

Sacrificial Lambs, Clive Phillips

Animal Sentience

Sheep evolved from the mouflon as mountain animals, able to escape predation by leaping between rock ledges. Their defense was their agility. Humans brought them to the plains, where the agility was less useful, but their lack of aggression, speed or weaponry against predators made them a prime target to become one of man’s meat providers. A perfect animal in many ways, with extraordinary perceptive powers and some remarkable cognitive skills, they are often treated with complete disregard for their welfare. Yet sheep themselves won’t tell us this, for a sheep that alerted others to its weakness really would be …

Pulling The Wool From Our Eyes, Jennifer Vonk

Animal Sentience

Marino & Merskin review evidence of the complexity of sheep cognition, concluding that researchers ought to feel sheepish about misrepresenting ovine cognitive capacities. However, the failure to situate the data in critical context risks pulling the wool over readers’ eyes.

Is Knowing Enough To Change Human Attitudes And Actions?, Liv Baker

Animal Sentience

Marino & Merskin present evidence on key aspects of cognition, such as theory of mind, learning, emotional valence, and sociality, to make a convincing argument that sheep are due consideration as individual sentient beings. With this information, what will it take to produce a real, meaningful shift in our attitudes and actions towards other animals, including a species as disadvantaged as sheep? What else do we need to know?

Reflections On Sheep Rearing, Joyce D'Silva

Animal Sentience

Sheep rearing has an incredibly long history. Sometimes this alone can give credibility and status to a human practice. In the twenty-first century, it may be time to reassess our treatment of sheep and their place in nature. “Just because we’ve always done it” no longer has validity by itself. There are many other human practices which used to be accepted widely in certain societies and which we now may find abhorrent. With sheep intelligence now rightly regarded as an acceptable area of research within the academic community, it is a good time to reflect on our treatment of these …

Casting A Sheep’S Eye On Science, David M. Peña-Guzmán

Animal Sentience

Marino & Merskin review evidence that sheep are not just passive and reactive creatures. They have personalities that vary from individual to individual and endure over time. It follows that we must rethink what it means to study them scientifically.

Far More To Sheep Than Meets The Casual Eye, Bernard Rollin

Animal Sentience

Marino & Merskin’s survey of the cognitive and social capacities of sheep is an eye-opener about the individuality and emotionality of this most maligned of all farm animals. My own eyes had already been opened by an adopted orphaned lamb, so much more like a dog as a companion animal than the mindless robot I had been conditioned to expect. I am morally certain that Marino & Merskin’s survey will have a similar effect on readers open to changing their minds.

Sentient Animals Do Not Just Live In The Present, John Webster

Animal Sentience

Sheep are particularly well-equipped with the cognitive and emotional skills appropriate to their phenotype and natural environment. These include spatial memory, the benefits of safety in numbers, and the ability to recognise special individuals in large flocks by sight and by sound. Marino & Merskin’s target article reviews convincing evidence on whether sheep are more or less clever than other mammalian species. Sheep are very good at being sheep. But sentient animals do not just live in the present. Their emotional state is not simply dictated by events of the moment. If they learn, they can cope; if not, they …

Positive Sentience Is Underrated, Teya Brooks Pribac

Animal Sentience

My commentary focuses on two aspects of ovine (well-)being considered in the review: the developmental context and (un)fulfilled potentialities.

Sheep In Aesop’S And Phaedrus’S Fables, Matteo Colombo, Chiara Raucea

Animal Sentience

Sheep feature in various animal fables. Marino & Merskin suggest that “we” view sheep as “docile, passive, unintelligent, and timid,” but animal fables do not support this view. In Aesop’s and Phaedrus’s fables, sheep are a primary target of injustice; but they are not passive targets. Sheep endure injustice actively and honestly. They are intelligent, aware and outspoken about their own condition.

Using Sheep Psychology To Guide Sheep Policy, Ralph Adolphs

Animal Sentience

Marino & Merskin’s valuable review of the literature on sheep cognition shows how entrenched common views of these animals’ mental lives are disputed by the research literature. Yet the evidence they muster faces three challenges that their target article does not discuss: (1) the behavioral tasks are strongly anthropocentric; (2) neuroscientific data are absent; and (3) applications are not discussed. I touch on all three of these here.

Why Are Sheep Sheepish? How Perception Affects Animal Stereotyping, Robert G. Franklin Jr.

Animal Sentience

Marino & Merskin present compelling evidence that many stereotypes of sheep are incorrect. One factor that may play an important role in animal stereotyping is the physical appearance of animals, which can directly lead to stereotyping through automatic mental processes. Sheep have a round and babyish appearance that directly evokes judgments of warmth and docility. Depictions of sheep in art, and especially cartoons, reinforce this stereotype.

The Mental Lives Of Sheep And The Quest For A Psychological Taxonomy, Carrie Figdor

Animal Sentience

Research into nonhuman cognition has broadened and deepened in recent years. It supports and motivates a shift toward an ecological rather than an anthropocentric approach to cognition.

Debunking Human Prejudice And Blindness, Peter J. Li

Animal Sentience

Human prejudice and blindness to animal suffering are shocking. Despite their differences in culture, politics, and religious beliefs, humans have one thing in common. They see nonhuman animals as inferior and have since time immemorial assumed a dominant position in an asymmetrical human-animal relationship. When it comes to human-animal relations, there is no “clash of civilizations.” Human prejudice and blindness are predicated on “common sense assumptions” about the natural world and nonhuman animals in particular. Marino & Merskin’s review is part of the growing effort to debunk the assumptions that have shaped human actions so as to end the injustice …

Applied Cognition Research To Improve Sheep Welfare, Kristina Horback

Animal Sentience

If a change is going to occur in the care and management of domestic sheep, there needs to be a collaborative effort across many disciplines. This review by Marino & Merskin of the literature on cognitive processing in domestic sheep is limited by the inherent bias of the authors, including the impracticable goal of eliminating sheep production. Animal welfare concerns about the management of commercial sheep are valid; however, in order to make a difference, we need to develop an application for this knowledge about cognitive abilities in sheep.

Guilty As Charged, Sergio M. Pellis

Animal Sentience

Sheep have had a bad rap with regard to their behavioral capabilities, and to a large extent, that negative view of sheep has arisen from our failure as human observers to view the world from the perspective of the sheep themselves. Studies sensitive to what sheep identify as of value in the world have revealed a different picture: sheep have cognitive, emotional and social complexity beyond our crude stereotype. Clearly, what we need to do is to evaluate non-human animals on their own terms and not as a reflection of ourselves.

Sheep Complexity Outside The Laboratory, Cheryl Abbate

Animal Sentience

Marino & Merskin’s review shows that sheep are intelligent and highly social but their methodology has some shortcomings. I describe five problems with reviewing only the academic and scientific literature and suggest how one might provide an even more compelling case for the complexity of sheep minds.

Cognition, Emotion, Personality And The Conservation And Management Of Wild Ungulates, Rob Found

Animal Sentience

Increasing public understanding of the complexity of wild ungulates can improve animal welfare and advance global conservation efforts of these keystone species. Unfortunately, shaping public opinion on wild species is challenging because personal experience with wildlife is declining, popular education is still biased towards the predator instead of the prey, and scientific research is more difficult to conduct on wild ungulates compared to those on farms, in zoos, or otherwise in captivity. Nevertheless, studies of cognition, individuality, and intelligence of wild ungulates are increasing. I briefly highlight some major results from my own work on complexity in wild elk, illustrating …