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Tag: evolution

How farming changed dogs — and us

bread

It’s no big surprise — given it’s what led them to befriend us in the first place — that dogs have been dining on our scraps since early in their domestication.

What’s more interesting is how dogs adapted to our junk food ways.

A team of researchers from France, Sweden and Romania has found evidence indicating that domesticated dogs underwent a genetic transformation, developing multiple copies of a gene that aids in the digestion of starch.

That’s the same thing we humans did, when we made the transition from a hunting to a farming society, consuming more starches and vegetable and less meat.

In their paper published in the journal Royal Society Open Science, the team describes what they found out by conducting a DNA analysis of ancient dog teeth and other bones.

They conclude that, around 7000 years ago, domesticated dogs were eating so much wheat and millet they made extra copies of starch-digesting genes to help them cope.

starchIn other words, as we began consuming more starches, so too — via our leftovers — did the dogs that were compromising their wolfy ways to hang around with us.

That we and dogs can have our genes altered by the food we consume and the repeated behaviors we engage in, is kind of intriguing, and kind of scary — and it brings new credence to the old phrase “you are what you eat.”

Some of the first insights into how farming changed the canine genome came three years ago, according to Sciencemag.com

That’s when a team led by evolutionary geneticist Erik Axelsson of Uppsala University in Sweden discovered that dogs have four to 30 copies of a gene called Amy2B, whereas wolves typically only have two.

The new study sought to get a better handle on when that happened.

Axelsson teamed up with Morgane Ollivier, a paleogeneticist at Ecole Normale Supéieure de Lyon in France and others, who extracted ancient DNA from the bones and teeth of 13 wolf and dog specimens collected from archaeological sites throughout Eurasia.

Four of the ancient dogs — from a 7000-year-old site in Romania and 5000-year-old sites in Turkey and France — had more than eight copies of Amy2B, Ollivier and his colleagues reported in Royal Society Open Science.

The findings rule out a modern origin for the increase in the number of Amy2B genes in dogs.

pastaDogs were likely domesticated more than 15,000 years ago, and likely continued eating mostly meat after that, as they became hunting companions to humans.

As humans turned to farming, the number of copies of Amy2B increased — first in us, then in dogs.

Being able to survive on whatever humans discarded likely enabled dogs to become widespread as people migrated across the globe, the scientists say.

It’s food for thought — how what we eat, or other repeated practices, can lead, far down the road, to alterations in our DNA.

Might scientists discover, generations from now, for example, that we humans have developed a selfie-taking gene that won’t let us stop taking excessive photos of ourselves?

They’ll name it 02BME.

Bear dogs once roamed Texas, or, why it’s important to check that miscellany drawer

beardog

Every home has at least one — that drawer in which you place things that have no assigned place: rubber bands, soy sauce packets, take-out menus, the owner’s manual to that extinct VHS player you bought in the 1980s.

Such drawers become a crypt for things you mostly didn’t need to keep in the first place, but often there are some forgotten treasure mixed in with them.

The importance of revisiting the miscellany drawer from time to time is displayed in this story — about a researcher at the Field Museum in Chicago, new on the job, whose opening of a drawer of miscellaneous and not fully identified carnivore fossils led to the establishment of not just one new genus, but two and, in doing so, a better understanding of the evolution of dogs and other mammals.

“I had just started at the Field, and I was getting the lay of the land, exploring our collections,” Susumu Tomiya said. “In one room of type specimens, the fossils used as a standard to describe their species, I stumbled across something that looked unusual.

“There were beautiful jaws of a small carnivore, but the genus the specimen had been assigned to didn’t seem to fit some of the features on the teeth. It made me suspect that it belonged to a very different group of carnivores.”

That specimen, and a similar one Tomiya came across, had both been found 30 years ago in southwest Texas.

beardog-jawBoth had been labeled as belonging to a genus called Miacis, but Tomiya’s suspicions — based on the apparent sharpness of their teeth — turned out to be right.

The findings were revealed last week in a paper published in the journal Royal Society Open Science.

Tomiya and his coauthor used a computed tomography (CT) scanner to create 3D visualizations, and determined the specimens were those of amphicyonids, and the oldest known members of that family, which went extinct 2 million years ago.

Amphicyonids, commonly called bear dogs, are believed to be the ancestors of both bears and dogs.

“Ever since amphicyonids were given their common name, they have been overshadowed by the bear and dog families, which are more widespread, better known today, and less extinct! Our study provides a renewed sense of identity to a group that left their own mark during their 38-million-year history,” Tseng said.

Amphicyonids ranged from the size of a Chihuahua to the size of a brown bear.

They tended to get larger throughout their evolutionary history, which might have contributed to their extinction.

(At top, artist’s reconstruction of a 38 million year old amphicyonid, by Monika Jurik; lower photo, the jawbone of an amphicyonid; both provided by The Field Museum)

Fossils found in Maryland identified as those of ancient dog species

cynarctuswangi

If you were wandering around Maryland 12 million years ago, you might have run into this fellow.

You wouldn’t have know what to call him, though, because only now does his species have a definite name — Cynarctus wangi.

Fossils found by an amateur collector along the beach under the Choptank Formation in Maryland’s Calvert Cliffs region have been identified as the news species of ancient dog by a doctoral student at the University of Pennsylvania.

The specimen, found in Maryland, would have roamed the coast of eastern North America approximately 12 million years ago, Science Daily reported.

Among species that still roam the earth, Cynarctus wangi probably most closely resembles the hyena.

“In this respect they are believed to have behaved in a similar way to hyenas today,” said Steven E. Jasinski, a student in the Department of Earth and Environmental Science in Penn’s School of Arts & Sciences and acting curator of paleontology and geology at the State Museum of Pennsylvania in Harrisburg. His new findings were published in the Journal of Paleontology.

Fossils from terrestrial species from the region and time period are rare, he said.

“Most fossils known from this time period represent marine animals, who become fossilized more easily than animals on land,” Jasinski said. “It is quite rare we find fossils from land animals in this region during this time, but each one provides important information for what life was like then.”

Jasinski and Steven C. Wallace, a professor at East Tennessee State University, began their study after the specimen was placed in the Smithsonian Institution.

Initially, they presumed it was a known species of borophagine dog, a species called marylandica that was questionably referred to as Cynarctus, a fossil of which had been found in older sediment in the same area.

But when they compared features of the teeth of the previously known and the new specimens, they found notable differences and concluded the specimen represented a distinct species new to science.

“It looks like it might be a distant relative descended from the previously known borophagine,” Jasinski said.

Borophagine dogs were widespread in North America from around 30 million to about 10 million years ago. The last members went extinct around 2 millions of years ago during the late Pliocene.

Cynarctus wangi represents one of the last surviving borophagines and was likely outcompeted by ancestors of some of the canines living today: wolves, coyotes and foxes.

The name of the new species honors Xiaoming Wang, curator at the Natural History Museum of Los Angeles County and an expert on mammalian carnivores.

(Illustration from “Dogs, Their Fossil Relatives and Evolutionary History,” courtesy of the University of Pennsylvania)

It’s official: Dogs are chick magnets

chick magnetA new study has confirmed what many of us guys already knew, or at least suspected — having a dog can make us more appealing to women.

The study goes a step beyond stating the obvious, though, looking at why that is, and why using a dog as date bait — unfair as it may be — works better for men than women.

Titled “The Roles of Pet Dogs and Cats in Human Courtship and Dating,” the study was published this month in the quarterly research journal Anthrozoos.

It surveyed random Match.com users in the United States who included pet information in their dating profiles. More than 1,200 individuals took part.

The study found women put far more stock in a potential mate’s associations with pets — and particularly dogs —  than men did.

Women were more than twice as likely as men to say they were attracted to someone because he had a dog. They were also twice as likely to judge a date based on how he interacted with his dog.

Why? The researchers hypothesized that it’s probably based on evolutionary instincts. Women tend to seek a partner who they think will make a responsible parent, while men are more likely to look for … well, we all know what they are looking for.

“Put in terms of evolutionary and life-history theory, females allocate a higher proportion of their reproductive effort to parenting while males expend more energy on mating,” the researchers said.

In other words, a man with a dog is seen as a more nurturing and responsible member of his gender and therefore, the line of thinking goes, will make a better daddy.

While dogs may help draw women to a man, the reverse isn’t quite as true, the researchers found.

When women see a guy with a dog, they see a man who is responsible and wants to settle down, and they are charmed. When men see a woman with a dog, they too see a person who is responsible and wants to settle down, and they — or at least the less evolved among them — get scared. Or so the researchers’ theory goes.

As the study noted, men have caught on to the fact that a dog can improve their odds with the opposite sex. Twice as many men as women admitted they’ve used their dog to lure a potential date.

So who’s to know whether that guy in the park playing with his puppy is a nurturing soul, or simply a con man posing as a nurturing soul, using his dog in the same way he might use Axe for men?

Women. That’s who. And I wish them luck.

(Bulldog wearing the Zelda Chick Magnet Halloween costume, from Baxterboo.com)

If not for dogs, we’d all be Neanderthals

evolution

There’s no question humans played a major — you could even say heavy-handed — role in the evolution of dogs.

But might dogs and their predecessors have played an equally significant role in our’s?

invadersA new book by Pennsylvania State University anthropologist Pat Shipman, “The Invaders: How Humans and Their Dogs Drove Neanderthals to Extinction,” suggests that having wolves/dogs on our side allowed humans to survive while Neanderthals went extinct.

(Well, maybe not totally extinct; I know at least two.)

In reality, most humans today — thanks to long-ago couplings between humans and Neanderthals — have anywhere from one to four percent of Neanderthal genes in their systems. (Those genes, I suspect, are responsible for making us tailgate, become bodybuilders and cut in line.) 

Neanderthals lived, evolved and pretty much ruled for about 250,000 years. After humans came along, about 40,000 years ago, the numbers of Neanderthals declined, then vanished, falling victim, some think, to the superior intellect, skills and weapons of early humans.

Shipman agrees with that theory, but argues humans having wolves on their side was a critical factor.

Neanderthals, the author says, never buddied up with the wolf, while humans would go on to form an alliance with them, tame them, breed them and assign them the kind of tasks that helped with survival — like hunting, guarding and chasing away enemies.

Given dogs were once thought to have been domesticated only 10,000 to 15,000 years ago — long after Neanderthals and humans had it out — little attention was paid to what, if any role, they might have played in the conflict.

But newer evidence, suggesting the domestication of dog goes back 25,000, 35,000, or even more than 100,000 years ago, lends credence to the conclusion dogs were a factor in the survival of our species.

It’s all pretty fascinating stuff — from whence we came, from whence dog came, and how, when and why we seemingly became allies.

But, other than the fact that knowing how our species has managed to survive this long might help it continue to do so, I’m not sure how relevant it is to modern times — unless, as one writer semi-playfully suggests in a piece for WBUR, Boston’s NPR station, how much an individual likes or dislikes dogs is related to the amount of Neanderthal within.

“Depending on the individual, you might just wonder if dog loving might be an indicator of the ratio of Neanderthal genes you’ve got,” Vicki Croke wrote on the WBUR blog, “The Wild Life.” She quotes Lauren Slater, author of  “The $60,000 Dog:”

“What this may mean: all those ‘not dog’ people, the ones who push away the paws and straighten their skirts after being sniffed, well, they may have one foot in the chromosomally compromised Neanderthal pool,” Slater wrote, while dog lovers “may be displaying not idiocy or short-sighted sentimentality, as our critics would call it, but a sign of our superior genetic lineage.”

So the next time some small foreheaded, prim and proper, club-carrying type asks that you keep your dog away from them, by all means comply, but feel free to mutter under your breath as you walk away:

“What a Neanderthal!”

Who’s the fool: Why do we humans persist in our efforts to trick the dog?

SONY DSC

Most of us have probably tried a version of this at home — be it with the fake tennis ball toss, the hidden treat or the imitation door knock.

How easily, and how many times in a row, can we fool the dog?

For some reason — maybe to test their intelligence, more likely because of the puckish tendencies of our own species — we seem to like to prank our pets.

Even many of your more admirable dog owners aren’t above punking their pugs, confusing their corgis, tricking their terriers or discombobulating their dachshunds.

My dog Ace has fallen victim to most of them. I’ve rapped against the wall to make him think someone’s at the front door. I’ve pretended to throw sticks and balls and hidden them behind my back as he gives chase. (This may explain why he’s not great at fetch). And, in perhaps the cruelest torment of all, I’ve made him think I’m holding a treat in one of my hands, holding out two closed fists and letting him pick one, then the other, only to find both are empty.

With each, he quickly caught on to the fact he was being played, and, despite my attempts to continue teasing him, moved on to something more interesting than me — like a shrub, or a rock, or the couch.

Dogs, due to their trusting nature, can be pretty easily fooled the first time. But you’re not likely to fool them with the same trick more than once or twice, according to a new study, published in the journal Animal Cognition.

Thirty four dogs were involved in the study, conducted at Kyoto University in Japan. One at a time, they were taken to a room where a researcher pointed to where food was hidden in a container. All the dogs followed the cue and got the treat. The second time around, the researchers pointed to an empty container, and all the dogs followed the cue , only to be disappointed.

The third time around, when the researcher again pointed to a full container of food, hardly any of the dogs bought it.

When a new experimenter came in to try again, the dogs initially trusted him — at least until he duped them, too. (Thank you, dogs, for not judging our entire species based on the acts of one.)

The leader of the team that conducted the study, Akiko Takaoka, says its findings suggests dogs are pretty good at determining how reliable an individual human is.

“Dogs have more sophisticated social intelligence than we thought. This social intelligence evolved selectively in their long life history with humans” she told BBC. Dogs understand what it means when a human points at something. If a dog’s owner points in the direction of a ball, stick or food, the dog will run and explore the location the person is pointing to.

But Takaoka said she was surprised that the dogs “devalued the reliability of a human” so quickly.

I wonder if the results might have been different if dog owners — rather than strangers — were the ones trying to fool them. Would they, based on the bond they have with their owners, be a little more trusting, and follow the cues a few more times before giving up?

Maybe … assuming their owner hasn’t raised them with a steady diet of pranks.

Fun as they may be, they should probably be done in moderation, and not during puppyhood. And, when it comes to training, it’s probably best to avoid duping our dogs into doing what we want them to do — as in tricking him into a bath, or into the crate, or using the word “treat” to get him to come. Deception — with the possible exception of putting his pill in a shroud of cheese — shouldn’t be something we regularly practice to control our dog.

Dogs like things to be predictable, John Bradshaw of the University of Bristol notes in the BBC article, and not knowing what’s going to happen next can make them stressed, fearful or even aggressive.

“Dogs whose owners are inconsistent to them often have behavioral disorders,” he said.

Still, many of us (perhaps due to our own behavioral disorders) persist — even those who know fooling the dog runs counter to good training, and works against building a relationship of trust.

Why we’re that way might be equally worthy of a study. Why, long after the dog has lost interest and moved on to something else, do some of us humans continue to try and amuse ourselves by tricking them?

Maybe those people are scientists at heart, and want to test their dog’s cognitive abilities. Maybe they justify it by telling themselves — as I did when teasing my little brother — that it’s building character, or teaching our dog that life isn’t always fair. Maybe they’re trying to establish their dominance, or at least their feeling of mental superiority, or re-establish the fact they are in control. Maybe they have a tiny cruel streak.

More likely, they are just seeking a laugh, or feel the need to confirm how much their dogs trust them.

The occasional prank, I think, is OK, but pulling too many of them might be an indication we’re not worthy of that trust, leading it to erode, as maybe — based on the experiment in Japan — it is already.

Dogs are continuing to figure us humans out (no small task). They learn our schedules. They predict our actions. Apparently, they have also learned when, amid our trickery, to turn us off, in which case the joke just might be on us.

Study says dogs go back no more than 12,000 years

skulls

A new study has a bone to pick with earlier researchers who concluded the domesticated dog has been around for 30,000 years.

New 3D analysis of skulls that had been identified as two of the earliest dogs shows they were actually wolves, a research team writes in the Nature journal Scientific Reports.

Fossilized remains that scientists said showed dogs date back at least 31,680 years — specifically those remains unearthed at Goyet Cave in Belgium — actually belonged to a wolf, according to a new study. So too, the new study says, did a 13,905-year-old fossil that was identified as belonging to a dog after it was found at a site called Eliseevichi in Russia.

The new study concludes that the the domestication of dogs happened during the Neolithic era (10,200 B.C.-2,000 B.C.) as opposed to the Paleolithic era (2.6 million years ago to 10,200 B.C.)

“Scientists have been eager to put a collar on the earliest domesticated dog,” lead author Abby Grace Drake said. “Unfortunately, their analyses weren’t sensitive enough to accurately determine the identity of these fossils.”

“Previous research has claimed that dogs emerged in the Paleolithic but this claim is based on inaccurate analyses,” Drake told Discovery News. “We reanalyzed some of the fossil canids from the Paleolithic and show that they are, in fact, wolves.”

“We did confirm that the Neolithic specimens Shamanka II (around 7,372 years old) and Ust’-Belaia (about 6,817 years old) are dogs, and therefore domestication took place by this time period or earlier,” added Drake, an assistant professor of biology at Skidmore College.

That means the wolves — who are generally (but not unanimously) believed to have evolved into dogs, possibly as a result of their interacting with humans — first appeared on earth after humans were farming and living in settlements, as opposed to when they were living in caves and hunting and gathering.

Drake and colleagues Michael Coquerelle and Guillaume Colombeau used scans and 3D visualization software to study the shape and size of the two oldest skulls and compare the data with measurements from the skulls of other dogs and wolves, according to a report on Phys.org.

That technique allowed the team to identify subtle morphological differences between dogs and wolves, such as the direction of the eye cavity and the angle between the muzzle and forehead.

(Photo: Abby Grace Drake, Skidmore College)