#Ctenophores Semaphore Information About Earliest Animals This article was published originally at The Conversation. The publication contributed the article to Livescience's Expert Voices:
Most of us have heard never of Ctenophores or comb jellies but this is about to change. In a publication out today in Science a team of researchers in the computational genomics unit at the National institutes of health in Maryland report that Ctenophora are the most ancient multicellular animals.
This was a spot previously held by sponges. To understand the implications of this finding we have to remember that multicellularity was a big step in evolution that occurred over 550 million years ago.
At the time there was an explosion of forms as life explored the limitations and possibilities of having a body made up of different types of cells.
The arrangement of cell types continues to be the basis of animal classification. Sponges were the obvious choice for the first experiment in cellularity as they have no nervous system few cell types and no organisation of tissues.
Studying evolutionary patterns relies on comparing genetic information. Animals that appear superficially similar (such as jellyfish
and comb jellies) can be quite different at a genetic level. Modern taxonomy has embraced barcoding which uses the DNA sequence of a single gene to distinguish between closely related species
. But one gene never tells the whole story and when looking back to the beginning of metazoan evolution even multiple genes can lead us astray.
The breakthrough in today s paper is the sequencing of the entire genome of a Ctenophore known as the sea walnut (Mnemiopsis leidyi.
Porifera (sponges) Cnidaria (jellyfish and anenomes) and Placozoa (there is no common name for Placozoa. Together these animals comprise the non-bilateria
which only makes sense when you realise that most of the animals we know are Bilaterians:
insects and fish and people and dogs all have bilateral symmetry. It now appears that the closest relative of Bilaterians are jellyfish
while the most ancient animals are the comb jellies. Ctenophores are delicate translucent creatures. They have eight rows of comb plates with cilia that provide them with locomotion.
They are carnivorous hermaphroditic marine creatures that do not sting. The sea walnut (M. leidyi) is native to the western Atlantic
but has been introduced to the Black Caspian and North seas where it has caused serious environmental and economic damage by eating native zooplankton and fish.
Apparently it glows blue green when disturbed. In terms of cellular arrangements Ctenophores have a nervous system and all three major cell types (endoderm ectoderm and mesoderm).
) Sponges by contrast have no cell types and no nervous system. No wonder we thought sponges were the more primitive organism.
The sea walnut genome contained 16548 protein coding genes 44%of which shared homology-a type of ancestry-with non-Ctenophores.
Comparing these genomes with those of the other major animal groups allowed the authors to reject several hypotheses about early animal evolution.
The amount of computational effort to achieve these aims is hard to overstate with an average run of 205 days for the Bayesian computer analyses alone.
We can study cell types and body plans in two ways: by examining the tissues themselves or by comparing genetic pathways available to create certain tissues.
The latter approach has been used quite effectively in this study. For example Ctenophores have a nervous system and sponges do not
but sponges do have required the genes for nervous system development and function. This means that the ancestor of all animals may have had advanced quite an nervous system
and these structures (but not their genes) were lost in the lineage that led to sponges.
Another major finding concerned the development of the main cell types in early animals. Embryonic cell layers develop into specific types of tissues.
Ectoderm formed the skin and nervous system endoderm formed the gut and mesoderm provided the muscle.
Until recently it was thought that non-bilaterians lacked the mesoderm layer. Ctenophores however do have a third cell layer called a mesoglea which acts like muscle.
The genes that support mesoglea development are completely unique and sufficiently different from bilaterian mesoderm to suggest an independently evolved three-layer system in these seemingly simple forms.
As sea walnuts glow when disturbed so does this study shed light on some interesting assumptions about animal evolution.
The first experiments in multicellularity were not simple collections of cells without structures or communication.
Genes responsible for cell signalling were present even before the evolution of multicellular animals. This suggests single celled organisms were communicating with each other before they decided to organise themselves into bodies with different types of cells.
Second the three cell layers of well-known animals including ourselves is not unique nor is it a latecomer to animal evolution.
The earliest multicellular animals evolved their own form of mesoderm independently with unique genes allowing sophisticated biological organisation.
Third the ancestor of all animals had a nervous system which coordinated bodily functions. The nervous system was lost subsequently in the lineages that led to Porifera
and Placozoa but survived in the Cnidarians and the Bilaterians. Finally and most profoundly the shape of the evolutionary tree of all animals has taken on a new shape.
The earliest branch of the animal tree belongs to Ctenophora now confirmed to be the sister lineage to all other animals.
So don t confuse comb jellies with jellyfish. I think of the Ctenophores as a semaphore signalling some profound truths to us (in a blue green glow) across the vastness of time about animal origins and biological organisation.
Susan Lawler has received funding from the ARC in the past. This article was published originally at The Conversation.
Read the original article. The views expressed are those of the author and do not necessarily reflect the views of the publisher.
This version of the article was published originally on Livescience
#Culprit in Mysterious Elk Deaths Found A hunter stumbled upon a bizarre sight on a 75000-acre ranch north of Las vegas N m. on Aug 27:
the remains of more than 100 dead elk. Livestock deaths are not unusual but so many animals dying off
and doing so in what seems to be under 24 hours was puzzling to scientists.
Officials with the New mexico Department of Game and Fish investigated the mysterious elk deaths and ruled out several possible causes for the elk deaths including poachers anthrax lightning strikes epizootic hemorrhagic disease (an often-fatal virus known to affect deer and other ruminants) botulism poisonous plants
malicious poisoning and even some sort of industrial or agricultural accident. The investigation was hampered by the state of the elk:
Scavengers including bears and vultures ate most of the bodies with maggots and blowflies helping to reduce the elk herd to an eerie scattered sea of skeletons in the desert.
Spooky! Top 10 Unexplained Phenomena We couldn't find anything toxic in their stomachs and no toxic plants on the landscape said Kerry Mower a wildlife disease specialist with New mexico Department of Game
and Fish as quoted by the Santa fe New Mexican newspaper. As news spread some conspiracy-minded folk soon speculated about links to animal mutilations UFOS or even the dreaded Hispanic vampire el chupacabra.
Pond scum of death Through science and further testing of elk tissue samples and water samples the real killer has finally been found:
pond scum. Or more specifically a neurotoxin produced by one type of blue-green algae that can develop in warm standing water.
A bloom of this alga can be devastating to wildlife. In warm weather blooms of blue-green algae are not uncommon in farm ponds in temperate regions particularly ponds enriched with fertilizer according to a classic toxicology reference book Casarett and Doull's Toxicology:
Under these conditions one species of alga Anabaena flos-aquae produces a neurotoxin anatoxin-A which depolarizes and blocks acetylcholine receptors causing death in animals that drink the pond water.
In other words the elk herd suffocated to death unable to breathe. And the fast-acting toxin explains the animals'strange sudden deaths.
In this case the algae appeared not in ponds but in three fiberglass livestock watering tanks not far from where the elk died.
The elk also showed signs they had struggled on the ground further supporting neurotoxin poisoning. Based on circumstantial evidence the most logical explanation for the elk deaths is that on their way back to the forest after feeding in the grassland the elk drank water from a trough containing toxins created by blue-green algae
or cyanobacteria Mower said in a statement from the Department of Game and Fish. The algae-produced neurotoxin is similar to curare the famous toxin found in poison-tipped arrows used by South american indian tribes.
Though anatoxin-A can be deadly to other animals including dogs and cattle reports of human deaths are rare.
New mexico ranchers have been advised to sanitize their livestock tanks to prevent further wildlife deaths. Benjamin Radford M. Ed. is deputy editor of Skeptical Inquirer science magazine
#Daring to Trap Grizzlies, Researchers Tackle Population Puzzle It takes a trained team a healthy dose of caution
and about an hour of work to restrain a grizzly bear and get the samples needed for research on the iconic western species. This research that could help scientists solve a puzzling trend in the bear's population numbers.
Here's how it works: Researchers scout out an area where grizzlies are known to wander.
There scientists leave roadkill bait in a metal box-trap masked so the bears can't detect it.
Once the trap catches a grizzly scientists use a sedative to immobilize the animal. Then they have only an hour to take blood
and hair samples do some measurements and fit a radio collar on the animal before it wakes up.
A team led by the U s. Geological Survey (USGS) goes through this complicated procedure in the Yellowstone national park area about 70 to 100 times a year.
Despite the inherent danger the research is a critical means of gleaning information about the local grizzly population's health.
The safety of the animal is important as well as the safety of our research teams said Frank van Manen a researcher with the USGS who leads the interagency team.
You are working with a wild animal a very powerful wild animal. Obviously there's always a risk of something happening that we haven't seen before so vigilance is incredibly important here. 7 Iconic American Animals Researchers have conducted grizzly bear monitoring in various forms since 1973.
At that time Yellowstone was completing the closures of garbage dumps that had attracted bears. Because of these dumps the grizzlies started roaming for food in areas too close to the park's tourists leading to policies of euthanization and removal.
Surveys showed a decline in the grizzly population until the early 1980s. Then between 1983 and the early 2000s the overall population increased by somewhere between 4 percent and 7 percent a year.
Grizzlies are slow reproducers; they have two cubs once every three years and only become fertile at age four or five.)
That growth has leveled off however in the past decade. Current growth is estimated to be only as high as 2 percent a year.
Figuring out why is one of the reasons grizzly scientists are trapping and studying the bears.
Photos: Trapping Grizzly bears We estimate 600 to 700 bears in this population. Is it possible that we now have reached a density where the population is being affected by
what we call density dependent effect? van Manen said naming one question the scientists are asking.
This occurs when the growth of the population itself regulates its own size. In the specific case of the grizzlies he added this would mean that the older males are killing the young cubs.
Scientists have proposed competing theories on what's causing the population to level off however. One of the explanations focuses on whitebark pine an important food as grizzlies bulk up for hibernation in the fall.
Grizzlies eat caches of whitebark pine seeds embedded in the tree. Van Manen's team completed surveys of the whitebark pine population finding a marked decrease (74 percent) in the number of trees in the past few years.
As these pines are high-altitude trees growing best above 8000 feet (about 2400 meters) some have proposed that the warming climate might facilitate outbreaks of native mountain pine beetles
which kill off the trees. Climate change could mean the trees'high altitude can't protect them from infestations any longer.
The winter temperatures aren't cold enough to break the cycle for the beetles. One hypothesis is that we're going to see more frequent outbreaks
It's unclear how greatly this is affecting the grizzly bears though. In response to lost pine trees the animals could switch to eating more meat
or find other plants as a substitution van Manen said. The researcher's team has submitted a paper examining the body composition
and fat content of grizzlies over time taken from the samples obtained when the scientists trap the grizzlies.
While van Manen declined to give specifics about the results until they are published he said there are no major indications that body fat as a percentage of bear weight is declining This could with further study suggest that the food source isn't the explanation.
Other participants in the ongoing bear research study include the U s. Forest Service the U s. Fish and Wildlife Service the Wind River tribe and the wildlife agencies for Idaho Montana Wyoming.
Follow Elizabeth Howell@howellspace or Livescience on Twitter@livescience. We're also on Facebook & Google+l
Scientist Risked Execution for Fox Study (Op-Ed) Brian Hare is an evolutionary anthropologist at Duke university
and the founder of Dognition a website that helps you find the genius in your dog.
This post was an adaptation from his book The Genius of Dogs co-authored with Vanessa Woods (Dutton 2013.
and finally solved the puzzle of how the wolf turned into the dog. Â For almost a century Darwin's biggest idea had a hole in it.
To illustrate natural selection Darwin did not directly suggest that humans shared a common ancestor with apes.
Everyone knew that you could selectively breed dogs for certain physical characteristics like size or coat color.
while the firstâ wolf  changed into a dog or a wild boar into a pig.
 Belyaev began his experiment with the silver fox because he could disguise his work as a commercial endeavor.
Silver foxes were prized in Russia for their fur and Belyaev's official research objective was trying to breed foxes for better fur.
Adopt a Pet Fox for Science's Sake Instead of trying to create a domesticated species by selecting for each physical trait Belyaev selected for one simple behavioral trait
whether the foxes would approach a human hand. Â After only 45 generations the experimental foxes began to change in ways that might take thousands if not millions of years in the wild.
By the time I arrived years later to see the ongoing work Belyaev's experimental foxes were radically different from their control population.
They had smaller skulls and canine teeth. Their coats were splotchy and their tails were curled.
They also had floppy ears and barked. Â When I met the bred foxes for the first time one jumped in my arms
and licked my face. The difference between the experimental and the control foxes were remarkably like the differences betweenâ wolves  and dogs.
 Belyaev had done it. He had taken a population of wild animals and essentially domesticated them.
And not just that he had figured out the mechanism by which it happened not by intentionally breeding for each physical trait
but by selecting only for behavior. That is by allowing to breed those animals that were friendly toward people.
There was one more change I was interested in when I tested the foxes in 2004. My team's previous research had shown that dogs are remarkable at reading human communicative gestures.
Dogs were better than wolves and better than even humans'closest living relativesâ chimpanzees. The question was
whether Belyaev's foxes would share this talent for reading human gestures. Â They did.
This had huge implications to how scientists think about the domestication of dogs. The most common assumption is that some hunter-gatherer with a soft spot for cuteness found some wolf puppies
and adopted them. Â Instead the foxes raise the real possibility that natural selection may have shaped wolves into the first proto-dogs in a very similar way without intentional human intervention or control.
Ray Coppinger of Hampshire College and others have speculated that as humans began forming more permanent settlements over the last 15000 years a new canine food source appeared that led directly to the evolution of the dogs we know
and love garbage. Â Only those wolves who were least fearful and nonaggressive toward humans would be able to take advantage of that new source of food.
It would not have taken many generations for those friendlier wolves to undergo physical changes like coat color.
Soon the wolves stopped looking like wolves. Many would have splotchy coats and some would have had even floppy ears or a curly tail.
Like the foxes they too accidentally became more skilled at responding to the behavior of humans
and a new relationship began. Â It's not always easy being an evolutionary biologist in this day and age.
But whenever I start feeling sorry for myself I think of Belyaev working undercover with death never far from his door.
Belyaev's quiet heroism is something to aspire to and although the true magnitude of his discoveries was realized not until after his death in 1985 his work was an invaluable contribution that will have implications far into the future.
 Hare's most recent Op-Ed was Dogs Show IQ TESTS Aren't So Smart.
#Darwin's Frogs Are in Steep Decline Some of nature's most fascinating fathers may be at risk of extinction.
Male Darwin's frogs swallow their offspring in the tadpole stage incubate their young in their vocal sacs
Along with seahorses the frogs are thought to be known the only living vertebrates in which dads take on baby-carrying duties with special sacs that make them look pregnant.
40 Freaky Frog Photos Shrinking range Charles darwin first discovered the frogs while traveling in Chile in 1834.
Scientists who later studied the mouth-brooding animals found that there are actually two species naming one Rhinoderma darwinii (Darwin's frog) and the other Rhinoderma rufum (Chile Darwin's frog.
From 2008 to 2012 a team of researchers led by zoologist Claudio Soto-Azat surveyed 223 sites in the frogs'historical range from the coastal city of Valparaã so south to an area just beyond Chiloã Island.
The findings suggest Darwin's frogs have disappeared from or at least rapidly declined in many locations where they were recently abundant the researchers wrote in a paper published online June 12 in the journal PLOS ONE.
And Darwin's frogs don't seem to be adapting; the survey showed that the remaining populations were clinging to their shrinking native forests.
The researchers recommended that Darwin's frogs be listed as endangered by the International Union for Conservation of Nature (IUCN.
Chile Darwin's frogs meanwhile should get a possibly extinct tag the researchers said. Other factors could be contributing to the decline of Darwin's frog.
Their populations have taken a hit from volcanic eruptions in the southern Andes the researchers say. What's more the African clawed frog was introduced to Chile in the 1970s.
That species has been associated with the deadly fungal infection chytridiomycosis which has wiped out amphibian species across the globe.
if Darwin's frogs have been affected by the fungus in the wild but the researchers say it's worth investigating.
Extinct Aussie cousins Darwin's frogs once had a close analog in eastern Australia known as gastric brooding frogs.
Female gastric brooding frogs swallowed their fertilized eggs transformed their stomach into a uterus and gave birth to their sons and daughters through the mouth.
Earlier this year scientists from the University of New south wales announced that they had created early-stage embryos of gastric brooding frogs that were already forming hundreds of cells.
The team said they used cloning methods to implant the DNA-storing nuclei of preserved gastric brooding frog cells in the eggs of Australian marsh frog eggs.
Amphibians are on the decline worldwide. Besides being at risk of deadly fungal infections frogs salamanders
and their relatives are more vulnerable to environmental changes because they have permeable skin and a complex water-and-land life cycle.
In a recent report on the sharp decline of the creatures in the United states researchers found that amphibians have been disappearing from their habits at a rate of 3. 7 percent each year.
Take a gander at the cherry blossoms at the NPS's webcam. Follow Andrea Thompson@Andreatoap Pinterest and Google+.
The survey respondents reported a long list of challenges including cover-crop seed availability increased insect potential
which have devastated large bird populations in the Atlantic Forest of Brazil. With these birds which include colorful toucans
and cotingas locally extinct or barely hanging on the palm trees have no way to disperse their largest seeds.
As a result seed sizes are smaller in parts of the rain forest where large birds are missing finds a new study detailed in the May 31 issue of the journal Science.
Combined with climate change the result could be devastating for palms said study leader Mauro Galetti an ecologist at Paulista State university in Brazil.
Palm trees and Lost Birds of Brazil Shrinking seeds The Atlantic Forest runs along the coast of Brazil starting at the easternmost tip of South america and continuing approximately to the country's southern border.
Of that area about 80 percent is disjointed fragments too small to support large animals. As a result large fruit-eating birds have vanished
or nearly vanished from much of the forest. These birds swallow fruit seeds and spread them through their droppings over many miles making the animals crucial to the forest ecosystem.
Galetti and his colleagues studied seed sizes in 22 populations of palm trees some in fragments where hardly any large birds survive
and others where bird populations are relatively robust. Â They found that seeds are consistently smaller in sites without large birds.
Seed sizes vary but in areas with few or no large birds common sizes range from about 0. 3 to 0. 4 inches (8 to 10 millimeters) in diameter with almost no seeds a half-inch (12 mm
) in diameter. In areas with robust large-bird populations half-inch (seeds are common with some seeds reaching 0. 55 inches (14 mm.
In sites without large birds the researchers found that seeds with a diameter of a half-inch
or larger had nearly no chance of being dispersed away from their parent tree. Other factors such as soil fertility forest cover and climate could not explain the change in seed size the researchers reported.
Human action Using genetic data from the seeds Galetti and his colleagues created computer models to figure out how long it would have taken trees to evolve smaller seeds in bird-free zones.
For the plants that we studied it was 50 to 75 years Galetti said. It's quite fast.
Human deforestation in the Atlantic Forest dates back to the 1800s more than enough time for the observed changes to evolve.
and put back animals that are important and stop hunting he said. Follow Stephanie Pappas on Twitterâ and Google+.
Seventy percent of the world s plants and animals live in forests and are losing their habitats to deforestation.
and local populations who rely on the animals and plants in the forests for hunting and medicine.
but police and searchers had identified already the Smith property as among the most likely places where Terry Smith Jr. might be found.
#Do Bark beetles Affect Water Quality? This Research in Action article was provided to Livescience in partnership with the National Science Foundation.
Hydrological studies in the Rocky mountains involving the tiny mountain pine beetle a species of bark beetle have big implications for water resource management in Colorado and elsewhere.
A team of National Science Foundation-funded scientists is investigating how a rampant beetle infestation could change the quantity and quality of drinking water in Colorado.
Scientists say bark beetles have killed about 90 percent of Colorado's lodgepole pines 4. 5 million acres of trees.
In earlier years cooler temperatures in fall and winter checked bark beetle populations in western North america.
#Do'Smarter'Dogs Really Suffer More than'Dumber'Mice?(Op-Ed) Marc Bekoff emeritus professor at the University of Colorado Boulder is one of the pioneering cognitive ethologists in the United states a Guggenheim Fellow and cofounder with Jane Goodall of Ethologists for the Ethical
Treatment of Animals. This essay is adapted from one that appeared in Bekoff's column Animal Emotions in Psychology Today.
He contributed this article to Livescience's Expert Voices: Op-Ed & Insights. The question I ask in the title centers on the idea that supposedly smarter nonhuman animals (animals) suffer more than animals who are not as intelligent.
Indeed many people who write about other animals make this assumption as do those who develop
and enforce policies on which sorts of treatment are permissible and which that are not.
In the eyes of the United states Federal Animal Welfare Act animals such as mice and other rodents birds fish and invertebrates receive little
if any protection from extreme abuse and they're not even considered to be animals.
Indeed about 99 percent of the animals used in research are protected not by federal legislation
We are amending the Animal Welfare Act (AWA) regulations to reflect an amendment to the Act's definition of the term animal.
The Farm Security and Rural Investment Act of 2002 amended the definition of animal to specifically exclude birds rats of the Genus rattus
and mice of the Genus mus bred for use in research (Vol. 69 no. 108 4 june 2004).
Common sense tells us that the animals who are excluded from that definition of animal are indeed animals.
In 1994 I published an essay titled Cognitive ethology and the treatment of nonhuman animals:
and suffering are still being considered even in light of a plethora of new data on the cognitive and emotional lives of other animals.
and sentience based on more recent research on animals'fascinating minds and their capacity to suffer
Human-centric claims about the ways in which animals interact in their social and nonsocial worlds are often the basis for decisions about how animals can
or should be used by humans in various sorts of activities. Thus the treatment of animals is linked often tightly to how people perceive them with respect to their ability to perform behavior patterns that suggest that they can think
if they have beliefs desires or make plans and have expectations about the future. Much comparative research still needs to be done before any stipulations can be made about how an individual's cognitive abilities can be used to influence decisions about how she
and nervous systems are different from those of animals with whom humans identify most readily or with whom people are the most familiar.
When people are uncertain even only slightly about an animal's ability to experience pain
or to suffer that animal should be given the benefit of the doubt. Are dogs more intelligent than mice
and do they suffer more? To begin in the past twenty years since completing my cognitive ethology essay there has been an explosion in studies
and data concerning the cognitive emotionaland moral lives of animals. Scientists have uncovered numerous surprises about species that were assumed to be not all that smart or sentient.
not only the nature of the cognitive emotional and moral lives of animals but also how much they suffer
So asking if a dog is smarter than a cat or a cat is smarter than a mouse doesn't result in answers that are very meaningful.
Likewise asking if dogs suffer more than mice ignores who those animals are and what they have to do to survive
and thrive in their own worlds not in ours or those of other animals. Furthermore with respect to the original abstract and what I wrote in the essay itself a great deal of subsequent comparative research has shown that
what was taken then to be well-founded common sense about what animals know and feel based on solid evolutionary theory (e g.
Charles darwin's ideas about evolutionary continuity) has been borne out by numerous studies and many surprises have also been forthcoming.
It's bad biology to rob animals of the traits they clearly possess. For example we share with other mammals
and vertebrates the same areas of the brain that are important for consciousness and processing emotions.
Humans need to abandon the anthropocentric view that only big-brained animals such as ourselves nonhuman great apes elephants
and cetaceans (dolphins and whales) have sufficient mental capacities for complex forms of consciousness and for enduring deep suffering.
In addition numerous stories about the lives of animals have opened up areas of detailed research. Indeed as my colleague Dale Jamieson and I like to say the plural of anecdote is data
and anecdotes and citizen science are very useful for stimulating systematic research. With respect to some other areas I covered back in 1994 recently a group of esteemed scientists put forth the Cambridge Declaration on Animal Consciousness in
which they concluded Convergent evidence indicates that nonhuman animals have the neuroanatomical neurochemical and neurophysiological substrates of conscious states along with the capacity to exhibit intentional behaviors.
Nonhuman animals including all mammals and birds and many other creatures including octopuses also possess these neurological substrates.
And we need to keep the door open to the possibility that other vertebrates and invertebrates also feel pain.
Because access to my earlier essay is restricted let me include here some more of what
I wrote (with references to the original sources for this material available here) as it's extremely relevant to the argument that we need to take the pain
and suffering of less intelligent animals very seriously and that speciesist arguments about higher and lower animals need to be shelved.
Using the word'stupid'to refer to domesticated animals when compared to their wild relatives can certainly influence how one treats an individual said philosopher J. Baird Callicott of the University of North Texas. Perhaps as the late Já
There are no'unintelligent'animals; only careless observations and poorly designed experiments. What would be the implications of discovering that some animals are not all that cognitivethat they have impoverished relatively cognitive abilities
and lives or that they have fewer memories and fewer beliefs about the future? First we would have to show that these so-called cognitive'deficiencies'are morally relevant.
and animals a point raised by Guelph University's Ian Duncan. Second one could argue that
Not allowing certain expectations to be realized is a serious intrusion on those individuals'lives perhaps more serious than not allowing some expectations in animals with richer cognitive lives to be realized.
and the dog who does not get to go for one more run by the river are both having desires thwarted to the same degree totally.
if the memories of some animals are developed not well (they live in the present and lack the ability to know the passage of time) then their pains have no foreseeable end.
Thus I might know that my canid companion Jethro's pain might end in five seconds
Related to that line of reasoning is the observation by Alastair Hannay that many animals even those for
Those animals seem to try to remove themselves from situations that they find aversive ituations they seem not to prefer that resemble situations that normal human beings
and other animals do not prefer either. Even if those individuals do not imagine that there is something that is more pleasurable
which we are associated unfamiliar that is with a preference shown by an animal who we think is'not all that cognitive
It is possible that some animals experience pain and suffer in ways that we cannot yet imagine
As Cambridge university's Patrick Bateson points out it was rare in the past to find people taking seriously the possibility of insect pain
despite inherent shortcomings it is possible that preference tests that are developed for a broad spectrum of animals would help to shed some light on the phylogenetic distribution of sentience.
because when animals do not do what we expect them to do or when they do nothing it is possible that they are motivated not by the situation that we create.
As University of Pennsylvania researchers Paul Rozin Dorthy Cheney and Robert Seyfarth suggest there are as yet unknown factors that influence an animal's behavior.
For a complete list of references to research that informed this article see the original essay Do Smarter Dogs Really Suffer More than Dumber Mice?
More of the author's essays are available in Why Dogs Hump and Bees Get Depressed (New world Library 2013).
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