Pies: Dogs can smell about 1,000 times better than humans

Evidence: 45 • authority: 92

Not just avoidance: dogs show subtle individual differences in reacting to human fear chemosignals.. Recent olfactory studies suggest that human emotional chemosignals can alter dog behavior. However, their methods impeded a firm conclusion on whether dogs reacted to the scent directly or to the present human's unconscious response to the intraspecific stimulus. Moreover, whether these reactions differ between dogs has not yet been explored. Therefore, we investigated dogs' reactions to human fear or neutral chemosignals while shielding the present human from the smells. Dogs were first trained to approach a single empty target on command, before they were given the choice between two targe…

Evidence: 35 • authority: 72

The dog (Canis familiaris or Canis lupus familiaris) is a domesticated descendant of wolves. Also called the domestic dog, it was selectively bred during the Late Pleistocene by hunter-gatherers. Dogs and the modern gray wolf share a common ancestor. Dogs were the first species to be domesticated over 14,000 years ago, before the development of agriculture, though genetic studies suggest the domestication process may have begun over 25,000 years ago. Due to their long association with humans, dogs have gained the ability to thrive on a starch-rich diet that would be inadequate for other canids. Dogs have been bred for specific behaviors, sensory abilities, and physical traits. Dog breeds va…

Evidence: 33 • authority: 72

Olfactory receptors (ORs), also known as odorant receptors, are chemoreceptors expressed in the cell membranes of olfactory receptor neurons and are responsible for the detection of odorants (for example, compounds that have an odor) which give rise to the sense of smell. Activated olfactory receptors trigger nerve impulses which transmit information about odor to the brain. Vertebrates have a total of four olfactory receptor families: OR, TAAR, V1R/ORA, and V2R/OlfC. This article focuses on the OR family. This consists of members of the rhodopsin-like (class A) G protein-coupled receptors (GPCRs). OR forms the largest multigene family in vertebrates consisting of around 400 genes in humans…

Evidence: 29 • authority: 88

Humankind’s Best Friend vs. Humankind’s Best Food: Perceptions of Identifiable Dog vs. Pig Victims. Abstract Current animal victimology and speciesism research has predominantly focussed on anthropocentric speciesism (prejudice favouring humans over animals) and neglects pet speciesism (prejudice favouring pets over non-pets). Moreover, research rarely explores whether identifiability of animal victims affects perceptions of them in line with the identifiable ( human ) victim effect. Drawing on speciesism and dehumanization theories, the current experiment addressed these gaps in the literature by comparing 160 adult participants’ perceptions of a dog vs. pig victim of kidnapping. As predic…

Evidence: 26 • authority: 92

From Control to Clue: Integrating Olfaction into the Object-Choice Task for Domestic Dogs (<i>Canis familiaris</i>).. Humans rely heavily on vision for information-gathering, decision-making, and communication, making it difficult to imagine how our perception of the world might change if our primary sensory modality were entirely different. Dogs ( Canis familiaris ), for instance, rely as much or more on olfaction as on vision in information-gathering. Nonetheless, canine cognition research has largely emphasized visual tasks. In the present study (N = 48 dogs) we aim to begin to remedy this by designing an olfactory version of a prototypical dog-cognition experimental design:…

Evidence: 26 • authority: 72

A working animal is an animal, usually domesticated, that is kept by humans and trained to perform tasks. Some are used for their physical strength (e.g. oxen and draft horses) or for transportation (e.g. riding horses and camels), while others are service animals trained to execute certain specialized tasks (e.g. hunting and guide dogs, messenger pigeons, and fishing cormorants). They may also be used for milking or herding. Some, at the end of their working lives, may also be used for meat or leather. The history of working animals may predate agriculture as dogs were used by hunter-gatherer ancestors; around the world, millions of animals work in relationship with their owners. Domestica…

Evidence: 24 • authority: 92

'Teleonomes in Tatters': The Welfare Costs of Selecting Dogs for Extreme Phenotypes, and the Case for Change.. The domestic dog is the most morphologically diverse domesticated mammalian species. That diversity has arisen from deliberate, sustained artificial selection over the most recent 1% of the domestic dog's evolutionary history. However, artificial selection has pushed many individual breeds so far from the ancestral canine form that many dogs within these breeds can no longer perform the critical biological functions their bodies evolved to serve. Indeed, much of the popularity of many dog breeds is predicated on them no longer being functional dogs; rather, they are representations…

Evidence: 24 • authority: 92

Canine "Sniffin' Sticks" enable behavioural olfactometry to complement neurological examination in dogs.. Olfactory function assessment in dogs remains limited compared to human medicine. This study aimed to develop a canine version of "Sniffin' Sticks" (canSSt) as a clinical behavioural olfactometry tool and to establish normative olfactory thresholds across sex, age, and cranial morphology in dogs. Eighty healthy client-owned dogs underwent clinical and neurological examination. A custom set of 15 felt pens containing serial tenfold eugenol dilutions (smell of cloves) was used to determine thresholds. Dogs were sequentially exposed to increasing concentrations. Behavioural responses were…

Evidence: 20 • authority: 72

Duffy antigen/chemokine receptor (DARC), also known as Fy glycoprotein (FY) or CD234 (Cluster of Differentiation 234), is a protein that in humans is encoded by the ACKR1 gene. The Duffy antigen is located on the surface of red blood cells, and is named after the patient in whom it was discovered. The protein encoded by this gene is a glycosylated membrane protein and a non-specific receptor for several chemokines. The protein is also the receptor for the human malarial parasites Plasmodium vivax, Plasmodium knowlesi and simian malarial parasite Plasmodium cynomolgi. Polymorphisms in this gene are the basis of the Duffy blood group system.

Evidence: 20 • authority: 72

Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized by removing a carboxyl group through decarboxylation from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. The brain includes several distinct dopamine pathways, one of which plays a major role in the motivational componen…

Evidence: 20 • authority: 72

The brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for special senses such as vision, hearing, and olfaction. Being the most specialized organ, it is responsible for receiving information from the sensory nervous system, processing that information (thought, cognition, and intelligence) and the coordination of motor control (muscle activity) and the endocrine system. While invertebrate brains arise from paired segmental ganglia (each of which is only responsible for the respective body segment) of the ventral nerve cord,…

Evidence: 20 • authority: 80

2. Dogs, Humans, and Retronasal Smell