Tag Archives: evolution

Wolfgang in March of 2004. Behind those sweet, glassy eyes lay eons of canine evolution and aggression.

I quietly strode towards the bedroom of my roommate, Tom*, merely expecting to find him asleep.  He had just experienced a heart-wrenching loss: putting his 11-year-old miniature schnauzer, Zane*, to sleep.  Surely, Tom was exhausted after a long road trip to and from the Northeast Texas town where he was born and raised; the same place where he’d raised Zane.

Zane and I bonded quickly when Tom and me agreed to pool our resources in May of 2002 and share a two-bedroom apartment.  I was working temporary gigs, and he had a courier job that left him feeling tired and uneasy.  After a car wreck and a major health scare in the fall of 2001, he had managed to put himself back together, while recuperating at his mother’s home back in that Northeast Texas town.  Zane’s presence, he told me, comforted him better than the medications he’d been prescribed and the alcohol he’d consume as an additive.

But, during the first week of August 2002, Tom had to return to his mother’s home to tend to a family crisis.  When he came back, I informed him that Zane was extremely ill.  I didn’t know what was wrong, but the shy little dog had shriveled up to the point where his ribs were visible.  Tom spent the next day in bed; holding Zane tightly.  He finally headed back to that Northeast Texas hamlet where Zane’s old veterinarian was also located.

Upon arriving at the veterinarian’s office, however, Zane suffered a catastrophic stroke…and never recovered.  “My little boy is gone,” Tom cried over the phone that evening from his mother’s house.

I cried with him.  So, while I was surprised to find Tom back at the apartment earlier than expected, I was even more surprised to see a tiny ball of silver and white fur crawling around on his bare chest.

On his way back to Dallas, Tom had stopped off in a town east of the city to visit a cousin.  In a purely spontaneous decision, he grabbed a newspaper and searched for a miniature schnauzer breeder.  He found one and purchased one of the eight-week-old puppies.  He named him Docker.  Where he came up with that I never knew.  But I renamed him Wolfgang a few months later.  That’s because he became my dog when Tom and I decided to go our separate ways in January 2003.

It’s one of the best decisions I’ve ever made; albeit an almost equally spontaneous move on my part.  In an uncertain time for me (I’d just started a new full-time job that felt insecure and I wanted desperately to move out of a complex that was going to hell), as well as for the nation (we were about to invade Iraq under false pretenses, and the economy remained fragile), taking custody of that dog stood out as a bright moment.  Tom left owing me some $700.  But I ended up with the dog.  I was ill-prepared to have a pet, yet I still felt I came out with the better bargain.

All of that came back to me Wednesday morning, as I carried Wolfgang’s quivering form into the veterinarian’s office.  He had gone into some kind of cardiac arrest episode…and never recovered.

Basic evolutionary tree of canines.

Wolfgang’s veterinarian had diagnosed him with a heart murmur a couple of years ago, which explained his occasional coughing / hacking fits.  Earlier this year, though, he began experiencing seizure-like episodes.  One in early May terrified me: he literally fell over onto one side; a cartoonish action that was anything but funny.  An X-ray proved his heart had enlarged and was clamping down on his airway.  The seizures, the doctor explained, were actually moments where Wolfgang couldn’t breathe.  He put him on two heart medications that would be a daily ritual for the rest of the dog’s life.  That life ended sooner than I’d expected – or even wanted.

“I just lost my father,” I whispered to him last Monday night, the 24^th.  “You can’t leave me also; not now.”

His behavior was actually quite normal this last weekend and into Monday, the 24^th.  Yet, by Monday evening, I could tell he had trouble breathing and began to suspect the worst.  Then it seemed the air around me had thickened, and I sense my father was nearby.

I tried giving Wolfgang the two medicines the doctor had prescribed back in May.  I literally had to shove them into his mouth; a little mouth lined with razor-sharp projectiles, backed up by eons of canid ambivalence.  I always tried to retract my hand as quickly as possible, but each time he managed to scrape my fingers.  Then, on Monday, he did something he’d never done before: he actually impaled one of his dental daggers into my right forefinger.  Blood oozed immediately from the gash, as I hurtled the tiny white pills into his food dish and marched into the bathroom.  My entire right hand throbbed.  It still aches.  But I don’t care.  He was just a dog.  More importantly, he continually spit out those pills.  I’ve found bits of them around the den area.  It was his last act of wolf-infused defiance and stubbornness.  Perhaps he sensed they were of no use at the moment.  He was done and wanted to move on from here.  Are dogs really that sentient?  Do they possess the same level of emotional capacity as their human counterparts?

A variety of studies over the past two decades suggest yes; dogs truly are more emotionally and psychologically complex than we ever realized.

I still find it amazing how we humans become so attached to certain animals.  For me, it’s always been dogs.  As far back as I can remember, I’ve held a special fascination with the canines among us.  Cats and horses are undoubtedly beautiful.  But I’m allergic to felines (as a 2004 allergy test proved), and horses are too big and expensive.  I’m an all-around animal lover, but dogs secured a tight grip on my mind and in my heart.

I often joked that Wolfgang wasn’t really a miniature schnauzer; he was a previously unclassified species of canine – a miniature wolf.  The big mocha brown eyes, soft fur and floppy ears (especially the right one, which rarely stood up, lest he tilt his head back at a certain angle) were just aesthetic ruses.  The mere mention of his name incurred occasional chuckles.

“The name fits,” I told people.

Artist depiction of Eucyon davisi, considered the direct ancestor of modern dogs.

Miniature schnauzers are among the 148 breeds of domesticated dog recognized by the American Kennel Club.  In addition, there are more than 150 other breeds of domesticated dog not officially acknowledged by the AKC, such as the Russo-European Laika, the Peruvian Inca Orchard, and the Prazsky Krysarik from Czechoslovakia, the world’s smallest dog.  Zoologists have also identified more than 100 species of wild canine, such as the South American bush dog, the Australian dingo, and the African basenji, the only dog that doesn’t bark.  It produces something of a yodeling sound.  Altogether, an estimated 10 billion dogs exist on planet Earth today.

Dogs boast an extensive and impressive lineage.  Canines have a longer and more diverse history than any other predatory carnivore, which allowed them to spread across the globe faster than fellow mammals.  They belong to the family of mammals called canidae and to the order of carnivora.  Zoologists believe all mammals descend from Creodonts, a group of small, meat-eating creatures that first appeared about 100 million years ago.  About 55 million years ago, during the Eocene Epoch, a more refined (but not much larger) carnivore, Miacis, arose in North America.  Miacis then evolved into Hesperocyon, or Hesperocyoninae – traditionally regarded as the direct ancestor of dogs – between 38 and 26 million years ago.  Hesperocyoninae generated 28 sub-species.   They were followed by Borophaginae, which produced 66 sub-species, and Caninae with 42.  One member of this latter group, a fox-sized animal called Eucyon, played the most critical role in canine evolution.

Arising in North America about 9 million years ago, Eucyon was omnivorous; a unique attribute that allowed it to survive longer than any of its predecessors and outlive even its contemporaries.  But Eucyon also had longer leg bones, especially the forelimbs, which increased its running efficiency and therefore, its ability to capture prey.  It had a shorter neck than most felines, another top predatory carnivore, which otherwise would have inhibited its ability to tear at flesh.  But Eucyon necks compensated for it with the nuchal ligament; a feature that permitted greater rotation of the entire neck column.

Adding to this was the extraordinary development of canine dentition (teeth) and the power of its jaw bones.  Together this allowed for actual bone-cracking of its prey.  The reason is obvious: inside animal bones is marrow, a rich source of protein.  Among all canine species the power of bone-cracking is no more evident than in the family of hyenas.  These wild African canines have been known to leave little evidence of a kill; they literally consume an entire animal.  Getting inside those bones with its mighty jaw strength helped canines retain their spot as top predators no matter where they migrated.

An artist’s rendition of the extinct Borophagus secundus canine from the late Miocene Epoch in North America displays the animal’s large dentition and low-angled skull that allowed it to engage in bone-crushing of its prey. Courtesy Mauricio Antón.

Between 6 and 4 million years ago, Eucyon began migrating across what is now the Bering Strait into Asia.  There it developed into Canis lupus, the gray wolf.  Canis lupus then spread further throughout Asia, eventually making its way into Europe, Africa, and India.  It also evolved into both variations of itself and canines such as dholes and jackals.  About 800,000 years ago canis lupus began tracing its ancestors’ migratory paths back into North America where it continued evolving; again into other wolf species, but also into such animals as the arctic fox and the coyote.

Throughout the next several millennia, wolves continually metamorphosed into various breeds of dogs.  At some unknown point, they formed an alliance with humans.  How, when and why this occurred are among the top questions for zoologists.  It’s quite likely that a human somewhere along the way found an abandoned wolf puppy and, feeling empathy for the animal, kept it and managed to raise it.  It’s also likely that canines began following humans, realizing the two-legged beings had a knack for capturing and killing large prey.  When the humans moved on, the canines would descend upon the remains of whatever animal was left behind.  This, of course, would make dogs scavengers, instead of hunters.  But, in a brutal world of survival, that’s what was necessary.

It’s more probable, however, that all of these incidents took place a number of times, all over the world and over a number of years.  As with other animals, such as horses and bovines, canine evolution eventually fell in line with human evolution; that is, their domestication coincided with the development of more complex and wide-spread human societies.

Skull, cervical vertebrae and muscle structure of the extant Canis lupus (gray wolf). The nuchal ligament allowed for greater movement of the head and neck.

The close relationship humans generated with dogs means people began subjecting these animals to selective breeding, in which they were propagated for specific purposes.  Initially, dogs served two primary roles in their union with humans: hunting game and herding livestock.  Later, they were bred to be protectorates, guides, and, of course, companions.  Consequently, we now have a plethora of dog breeds.  No other animal displays such an extraordinary level of diversity in size, color and shape as canines.

Dogs’ sensibilities are extremely acute.  While their visual resolving powers are less efficient than humans, their eyes are more sensitive to light and movement.  Dogs can hear sounds four times farther away than humans and are able to locate the source of that sound in six-hundredths of a second.  Dogs’ olfactory capabilities are their most extraordinary attribute.  The average dog has over 200 million scent receptors in its nasal folds, compared to a human’s five million.

Dogs are certainly among the most intelligent of mammals; perhaps the smartest among non-primates.  Like humans, dogs appear to be sensitive to vocal inflections and emotional queues.  A study at the University of Lincoln, United Kingdom, that dogs “form abstract mental representations of positive and negative emotional states, and are not simply displaying learned behaviours when responding to the expressions of people and other dogs.”

The researchers presented 17 domesticated dogs with pairings of images and sounds conveying different combinations of positive and negative emotional expressions in both humans and dogs. The sources of sensory input – photos of facial expressions and audio clips of vocalizations (voices or barks) from unfamiliar subjects – were played simultaneously to the dogs, without any prior training.  Researcher noted the dogs spent more time looking at the facial expressions which matched the emotional state of the vocalization.

Another study in Hungary went further by conducting MRIs on 13 dogs – six border collies, five golden retrievers, a German shepherd and a Chinese crested.  The animals were trained to lie motionless during the procedures, although they were awake and unrestrained.  Researchers found that dogs processed words with the left hemisphere and processed pitch with the right hemisphere – just like humans.

We’ll never know when the bond between humans and dogs was established.  Whether they save our lives, protect our property, or provide simple companionship, dogs are an indelible part of the human existence.  For dog lovers such as myself, that relationship is indescribable.

Basic evolutionary tree of modern dogs from their wolf ancestors.

* Name changed.

ASPCA

References:

“Dogs: Their Fossil Relatives and Evolutionary History.”  Richard H. Tedford & Xiaoming Wang. Columbia University Press, 2008.

“New Encyclopedia of the Dog.” Bruce Fogle, DVM. Dorling Kindersley, 2000.