A paramedic friend of mine from Austin has told me many amazing stories. One of the saddest was a call to the home of a solitary, elderly man. Neighbors had noticed the old guy hadn't been seen in a week or more, and when knocking on his door some reported hearing his young black lab's mournful cries. When paramedics entered the home it was a ghastly sight: The young dog was laying next to her very ripe master's body. The animal was looking emaciated, almost fatally dehydrated, probably not more than a couple of days from death. Despite the fact that there was a huge bowl of water and food just a few steps away in the kitchen. The dog had apparently not been willing to leave her owner to eat or drink. She even growled feebly in protection when they tried to approach. They forced the dog outside into the yard, brought out her food and water, and then packed up the corpse and drove away. Even with failing strength, the animal leapt over the fence and ran after the ambulance as far as she could; until she could no longer keep up ...
They are the most loyal companions anyone could ask for. They've been with us since before the encounter with European Neandertals and will probably be with us long after modern nations are footnotes in history. They hunt our food, eat our scraps, pull our sleds, protect our homes, guard against guns and drug runners, and lead the blind, all for an approving look and a scratch behind the ears. When we want to punish them for being naughty, we often do so by
Not allowing them to work!
Through thick and thin, war and famine, day and night, summer and winter, these animals have been our friends like no other creature on earth. Dogs come in long, skinny, fat, fluffy, hairless, wolfish, small, medium, large, and supersized. But one thing they all have in common; they do not judge us, they do not hold outbursts of anger against us, they don't care about money or fame or power. They forgive us unconditionally for every transgression we commit against them, in a heartbeat, with a wagging tail and that infectious canid smile. So this post is dedicated to the natural history of man's best friend, Canis lupus familiaris: Because I'm for dogs. But how did these incredible side kicks come to be?
Well, dogs are mammals of course and members of the family Canidae which includes dogs, wolves, jackals, dingos, foxes, and coyotes. Canids make up one of nine groups in the order Carnivora, which includes raccoons, and bears, as well as weasels, otters, skunks, and pinnepeds (Walruses, sea lions, seals) and cats. Carnivora arose from the hardy stock of critters such as basal Cynodonts, reptile-like mammals which predate the first dinosaur and have been around for a whopping 250 million years.
Cynodont
Genetic analysis of dog DNA indicates the order carnivora split from the precursors of primates like ourselves about 80-100 million years ago in the middle Cretaceous Period, and both primates and carnivora split from insectivores; something like Cimolestes although the details are murky, perhaps as early as 150 MYA in the late Jurrassic Period. Long before the dinosaurs were exterminated, the ancestors of dogs and people lived side by side in a strange evolutionary parallel of today. Both types of early mammals probably shared many a meal and competed for prey with one another in the nocturnal undergrowth of the ancient rain forests and woodlands dominated by ferns and pines, furtively scanning for raptorial predators of both the avian and terrestrial kind.
Every dog has his day it's said, but like all mammals, the Day of the Dog would not begin to dawn until after the saurian overlords of a now bygone world had left the evolutionary scene in the hands of their more adaptive mammalian underlings.
An early Miacid from the Eocene Epoch
In the late Paleocene, about 55 million years ago, the first recognizable candidate for a dog ancestor appears: The Miacids. These sleek carnivores, most about the size of a bobcat, radiated into an array of predatory eco-niches left by the vanquished giants in a few million years. Miacids likely hunted smaller prey in the rain forest canopies and dim floors of the Eocene jungles starting over 50 million years ago (MYA).
Cynodictis 35-40 MYA: A likely ancestor to modern canids, bears, and pinnepeds (Walruses, sea lions, and seals). Cynodictis was about the size of a fox and resembled a mongoose in several respects more than a modern dog. This creature had partially retractable claws and partially opposable thumbs indicating it was a proficient climber
Canid ancestors included smaller insectivores and later, much larger, tree climbing animals that probably walked on a five toes and may have even had partially retractable claws and partially opposable thumbs! These late miacids of 45 million years ago were wildly successful. Over the next ten or twenty-million years, as grasses evolved and grasslands began to replace dense forest, some of those early carnivores moved out of the treelands and onto the new plains and prairies, and even onto the coastal areas. Sometime shortly before or during that move is when they probably diverged into the ancestors of modern bears, walruses, seals, skunks, weasels, and of course, canids; wolves, foxes, coyotes, and so on. Those that remained behind in the jungles mostly retained their tree climbing skills and were on the evolutionary fast track to become the great cats.
Pseudocynodictis 25 million years in the past: Larger than Cynodictis, Pseudocynodictis was adapted to a more terrestrial existence and may have been a common ancestors of canids, and pinnipeds
By about 15 million years ago the first solid candidate for an ancestor to modern wolves appears, Tomarctus. This critter had lost the fifth toe leaving behind only a vestigial dew claw and likely developed the hunting strategies seen in large canids today.
Tomarctus at 10-15 MYA: This mean looking customer is the earliest known canid and may have been the forefather of modern wolves, foxes, and coyotes
By about two-million years ago the first wolves appear in the fossil record and split into a number of clades. One extinct species is called the Dire Wolf or 'cave wolf', star of novels, comic books, and an occasional cheesy sci-fi. It's a common misconception that dire wolves were much larger than modern day wolves. Both species were about the same height, length, and weight, but dire wolves had shorter legs, more robust skulls, and a more massive body. Dire wolves disappeared near the end of the Pleistocene and may have been specialized ice age predators which could not cope with the changing climate as the ice receded.
Genetic analysis of modern domestic dogs is a bit confusing, probably because of multiple interbreeding with extant populations of various subspecies of wolf, and perhaps even coyote, over the years. But there is good evidence that there were at least two main events in the lineage that became our trusted allies. Based on mitochondrial DNA analysis, two populations of the same species of wolf were domesticated and brought into the domstic breeding pool. The first was over fifty-thousand years ago, the second perhaps 15-20 thousand years ago. From poodles to Great Danes, your family pet is a subspecies of gray wolf.
The beautiful Gray Wolf and some gray wolf puppies, likely ancestor of all domestic dogs. The adult wolf is a member of the now famous Sawtooth Pack
Today dogs are with us on every continent, even Antactica. They have earned their keep, protecting our homes, pulling sleds, herding sheep and cattle, sniffing out guns and contraband, finding survivors under tons of rubble or buried in snow with their acute noses. Recent studies show that dogs can learn up to 200 spoken words, almost as many as chimps who are taught sign language. They don't ask for much, just to be near us, a few pets, and an occasional scrap of bacon: Like any best friend, all they really want is you.
What amazing animals eh? Let's meet a few!
Woof!
Dogs love a road trip!
Oh and the loyal black lab that chased after the ambulance until she pitifully collapsed in exhaustion? My friend couldn't stand it, but he couldn't allow a dog into the ambulance. So, he called animal control and consoled the poor thing until the catcher showed up and took her off to the pound. After he got off duty he hurried over to visit her ... and in a fit of sympathy took her home despite living in an apartment, saving her from the fate of so many unwanted animals.
She adapted well to her loss and to her new surroundings. Today, ten years later, dog, owner, and one of her many puppies, are now routinely seen exploring the scenic hills and trails of Central Texas, chasing squirrels, barking joyously at birds, catching Frisbees, and generally being ... well ... a happy dog!
My own sheltie puppy, 'Darwin', adds, "Have a wonderful weekend all and don't forget the bacon!"