by Elizabeth Blaker
Elders of the White Mountain Apache tribe still remember hearing wild wolves howling at night when they were children. I once heard the howling of wild wolves while camping at Glacier National Park in Montana. When you are sleeping outside at night and wolf song suddenly rises from somewhere out there, rises and falls and is answered by wolf voices farther off in the night, and nearer voices join in, the song filling the darkness and seeming to vibrate the stars overhead, that’s something you don’t forget.
Speak the word, ‘wolf’ in a crowded room in the Southwest, and you will hear opinions, strong opinions, perhaps shouts and fists slamming on tabletops. People in the Southwest either love the wolf or hate the wolf. Those who love the wolf speak about its vital role in the ecosystem, its beauty, and its symbolic and cultural importance. Those who hate the wolf are often cattle or sheep ranchers, hunting outfitters, guides, or hunters themselves (though there are some members of these groups who admire and respect the wolf); it’s a fact that wolves eat sheep and cattle, as well as elk and deer. This can cause serious difficulties for a ranching or guiding family that is only barely making it financially.
In 1998 the US Fish and Wildlife Service in partnership with other agencies released 11 captive-bred highly endangered Mexican Gray Wolves (Canis lupus baileyi) into the Blue Range Mountains in Eastern Arizona. The population in the wild is now about 60 wolves. The reintroduction of wolves in the Southwest raises complicated issues about ecosystems, livelihoods, and the role of us humans here on Planet Earth, topics worthy of consideration. This article is the first in a series of articles about wolves in the Southwest. In it I begin at the beginning – how did they get here?
The wolf came from Texas. Yes, you read that right. In 1977, Jack Wilson, a snaggle-toothed bespectacled paleontologist, unearthed the only fossil ever found of Prohesperocyon. Wilson found this most ancient ancestor of all living wolves at a dusty field site near an abandoned air field. (In Greek mythology, Hesperus was the evening star, son of the goddess of the dawn. Cyon means dog, or wolf – scientists are a romantic lot!). Although Wilson found only a skull and lower jaw, these bore unmistakable wolfish features, sporting only two upper molars instead of three, and a bulging bony case covering the inner ear called the auditory bulla. This skull was approximately 37 million years old, harkening to a time when the weather was so warm that there were no polar ice caps and a tropical forest covered North America all the way up to the latitude of northern Wyoming. Adapted to hunting small animals and hiding from larger predators in the dense forests, Prohesperocyon was about the size of a small fox.
That fact that only one fossil Prohesperocyon has ever been found suggests it was not a common animal in its time. Prohesperocyon was engaged in a desperate struggle for survival. Somehow Proshesperocyon managed to hang on, giving rise to a surprisingly successful heir, Hesperocyon.
During the time in which Hesperocyon and more recent wolf ancestors were evolving, the Earth’s climate was cooling and becoming dryer, forests were changing from tropical to deciduous, from dense to more open, and finally grasslands began to take over. With much less forest in which to hide, prey animals had to learn to run in order to survive, and they became swifter and swifter. Swift prey forced predators to become swifter, smarter. Some of them, such as the ancestors of the wolf, began to work together to take down prey much larger than themselves.
Compared to Prohesperocyon, the legs of Hesperocyon had become a bit longer and slimmer, and especially the lower portion of the leg. Over millennia, the toes of the wolf ancestors lost their splayed-out configuration and gradually aligned at the front of the foot, held tightly together. The foot became long and slim, with heels lifted high in the air so walking and running were always on the tips of the toes, an adaptation for fast running. The lower leg further elongated. Each of these changes gave the wolf ancestors a speed advantage over its competitors, including the larger and more powerful, shorter-limbed dire wolf.
Researchers hypothesize that when a predator increases in size to about forty-five pounds, it must become more reliant on large prey rather than small rodent-sized prey and insects. Think of the coyote, which weighs about thirty to forty pounds and eats a diverse diet of rodents, insects, even juniper berries. Occasionally coyotes working together bring down the odd deer or antelope, but they are not reliant on them for survival. Think of wolves, which are substantially bigger – research shows that they require an almost entirely carnivorous diet composed of deer, elk, rabbits and the like (though Farely Mowat reports in his famous account of wolves, ‘Never Cry Wolf’ that the arctic wolves he observed ate a lot of mice). Over thousands of years the wolf ancestors became larger and larger, which meant they needed to get faster and faster and to hunt in groups to bring down large prey in order to obtain a critical amount of animal flesh required for their survival.
About 7 million years ago during a time when great ice sheets were forming and the sea levels dropped, ancient wolves, looking very similar to those of today, made it north across the Bering Land Bridge to Asia and Europe. While the dire wolf still dominated south of the ice sheets, the modern wolf evolved in the frozen north. The ranges of wolves and the dire wolf expanded and contracted in lock-step as the ice sheets ebbed and flowed over the ages. Finally, with the extinction of the mammoths and other mega fauna at the end of the last ice age around thirteen thousand years ago, the dire wolf disappeared. This provided an opening for the return of the modern wolf its ancestral homelands.
Retaining its arctic ways, the wolf is a creature of high latitudes or high mountains. It makes sense for it to be thus because its prey, the elk and deer, also prefer these regions. Back in the Southwest, the wolf hunted among the pines, junipers and oak, down to the mid-elevation grasslands, but always avoided the desert.
In the diverse landscapes of the Southwest, the wolf itself began to diversify into several subspecies. In the mountains of Mexico and southern Arizona the first wolves to return from the frozen North gradually became smaller in order to live on leaner land with smaller prey animals. This subspecies is known as the Mexican Gray Wolf (Canis lupus baileyi). In the mid elevation pinyon juniper region of the Mogollon escarpment at the southern edge of the Colorado Plateau, a mid-sized subspecies, Canis lupus mogollonesis, evolved. In the White Mountains, and the Mountains of northwestern New Mexico, the large gray wolf Canis lupus youngi of the Southern Rockies dominated. In Texas, the Red Wolf, Canis rufus, migrated from the Southeast states. In the Texas panhandle and southeast New Mexico, Canis lupus monstrabilis evolved.
Genetic variation is like money in the bank for an animal against times of environmental change. The more variation a species has in essential characteristics like foot shape, leg length, jaw size, olfactory sensitivity, hearing acuity, fur density, etc., all products of random genetic mutations, the more likely it is that some of these traits will confer a survival advantage when the environment changes. This ensures that some members of the species survive even if others of its kind cannot.
Genetic analysis and fossil evidence suggests that the Mexican Gray wolf is a descendent of an early wave of wolves returning to the Southwest from artic regions, while the other subspecies of gray wolves are from later waves migrating southward, changing in response to different environments. Perhaps the Mexican Gray Wolf was driven down to more arid regions by the arrival of the larger wolves.
We have lost forever the Mogollon Wolf (Canis lupus mogollonensis), and some of the other wolf subspecies, too. We came within a hair’s-breadth of losing the Mexican Gray Wolf—the last five were captured from the wild and used to start a breeding program. The gray wolf, Canis lupus, has been removed from the endangered species list in many states because of rebounding populations, yet many of us fail to recognize the wealth of genetic diversity that has been lost forever. With the loss of genetic diversity all wolves are more vulnerable to extinction with any alteration in their environment. This in a time when a wave of massive global climate change is building and will soon break over us.
Not long after the 1998 their release in the Blue Range of Arizona, the wolves wandered onto Apache lands. Some of the Apache elders looked at these wolves and remarked that they were different from The Old Wolves, the wolf that they remembered from their childhoods – this reintroduced wolf, they said, was the wolf from the south, a smaller animal than The Old Wolf. It is clear that Apache elders retain important knowledge of the wolf. Nobody had asked the Apache elders their thoughts on the campaign to exterminate the wolf which began in the late 1800’s and nearly succeeded, and nobody asked them what they thought about the wolf reintroduction. That is, until Sarah Rinkevich, a young US Fish and Wildlife biologist went to the Apache elders and listened to what they had to say on the matter. She was told that the eradication and then the reintroduction of the wolf BOTH show an incredibly arrogant attitude towards the natural world.
Note: The next article in the series will tell the story of the reintroduction of the Mexican Gray Wolf in the Southwest and will highlight Sarah Rinkevich’s work.