Environmentalists like to claim that wolves are the “sanitizers” of nature and fill an essential role in maintaining a “balanced” ecosystem. The mantra goes that wolves only eat the old, the sick, and the disabled. Of course nothing could be further from the truth.
Wolf biologists and other wildlife observers in various countries all over the world have noted that wolves are able to sense disease and will choose to by-pass sick animals in order to prey on the youngest and healthiest specimens. Wolves do prey on injured animals, but often those injuries were caused by the wolves themselves. Wolves will bite through the hamstrings of large mature, and essentially healthy ungulates such as bull moose, bison, or elk and then return days or weeks later to finish off the animal after it has become severely weakened by blood loss and infection. Wolves prefer to prey on the very young and/or pregnant females whenever the opportunity arises.
Watch this video of a mother moose trying to protect her newborn calf:
This week a rancher in Wallowa County, OR reported that a pregnant cow had been killed by wolves. ODFW investigated the incident. Here is a portion of their report:
“Summary of evidence: The estimated time of death of the cow was early the morning of 1/28/13. A clear struggle scene was observed in the snow which showed multiple wolf tracks and large amounts of blood scattered over a large area of the carcass. Though partially consumed, ample carcass remained for investigation. The cow had suffered multiple bites in the typical wolf attack areas – behind the front shoulders, in front of the front shoulders and brisket area, groin and anterior portion of hind legs, and rump/udder area. Bites clearly showed heavy internal hemorrhage indicating pre-mortem attack. The fetus of the cow had been removed and mostly consumed – similar to past confirmed depredations of adult cows by the Imnaha Pack. All evidence (wolves present at scene, bite marks and locations, struggle scene with multiple wolf tracks, and internal hemorrhage) indicates wolf attack.” 
The rancher and ODFW estimated that the attack lasted over eight hours as the mother cow struggled to defend herself. Her fetus was eaten first, then the wolves began feeding on her uterus and hindquarters long before she died. Wolf packs have the capacity to kill any animal regardless of size or age and are extremely efficient at reducing the overall prey base. If spreading disease, destroying ungulate herds, and eating livestock is considered “sanitization”, then I guess the environmentalists have a point.
In previous posts I noted dozens of diseases spread by wolves, including parvo, mange, rabies and over 50 species of parasites, including hydatid disease. Without intense management, the natural population cycle between predator and prey species fluctuates wildly. If there is one thing the wolf is good at, it is their proficiency at killing other species by a variety of methods, both seen and unseen. The magnitude of the problem is best exemplified by Professor Valerius Geist who has proposed that to clean up the billions of hydatid cysts deposited in wolf feces every day across the landscape will require the systematic burning of millions of acres. Click here for Geist’s article entitled, Response to the Claims That Hydatid Disease Spread by Wolves Does Not Represent a Significant Threat to Humans.
There are numerous accounts suggesting that the wolf population grows exponentially in times of political unrest, climate change, famine and war. According to author Will Graves, the population of wolves in Russia spiked during both World Wars. 
The following excerpt is from an article entitled: World War 1 History: Russian Wolves, Business As Usual and War Horses by David Hunt:
“In the winter of 1916-1917, the Eastern Front stretched for more than a thousand miles from the Baltic Sea in the north to the Black Sea in the south. During that winter, half-starved Russian wolves converged on both the German and Russian lines in the northern part of the front in the Vilnius-Minsk region. As their desperation increased beyond their fear of humans, the wolves started attacking individuals but were soon attacking groups of soldiers so viciously and often that something had to be done. The soldiers tried poisoning them, shooting them with their rifles and machine guns and even using grenades against them, but the large and powerful Russian wolves were so hungry, fresh wolf packs simply replaced those that were killed.”
“The situation grew so severe that the Russian and German soldiers convinced their commanders to allow temporary truce negotiations to enable them to deal with the animals more effectively. Once the terms were worked out, the fighting stopped and the two sides discussed how to resolve the situation. Finally, a coordinated effort was made and gradually the packs were rounded up. Hundreds of wolves were killed during the process while the rest scattered, leaving the area once and for all to the humans. The problem was solved, the truce was called off and the soldiers got back to killing each other properly.”
There is something deeply disturbing to the human psyche about leaving a wounded comrade to be torn apart by wolves. Even when humans are engaged in the bloodiest forms of warfare, there is a limit to the barbarity we will tolerate.
 Will Graves, Wolves in Russia – Anxiety Through the Ages [c.2007] p. 58