Russia's military losses in Ukraine continue to mount. Here's a look at why the death toll is so high

While securing accurate fatality numbers from a war zone is very difficult, evidence is mounting that the Russian military casualty rate in Ukraine is extremely high.

NATO has estimated the number of Russian soldiers killed in Ukraine since the invasion began at between7,000 and 15,000. That higher estimate roughly equals the number of Soviet soldiers killedin over a decade of fighting in Afghanistan.

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According to a report in the New York Times in mid-March, United States intelligence officials said they were confident that up to 7,000 Russians had been killed by that point in the conflict.

The Washington Post reported around the same time that a Russian news website posted a file and then swiftly took itdown again claiming that up to10,000 soldiers had been killed so far in the conflict.

CBC News takes a closer look at why Russia's losses have been so high andhow long they canbe sustained, and the difficulty of getting accurate statistics out of a war zone.

How accurate are the statistics coming out of Ukraine?

While experts say there are reasons to believe some of the Russian fatality estimates are close to the mark, getting a clear accountof the battlefield death toll is almost impossible.

"In war conditions you have the fog of war, which makes it very difficult to get accurate numbers," said Walter Dorn, a professor of defence studies at the Royal Military College.

"In order to see deaths you'd have to go to places where there's people dying, which usually means there is a dangerous threat. So it's hard for objective observers to get that kind of number."

Stephen Saideman, the Paterson Chair in International Affairs at Carleton University and the director of the Canadian Defence and Security Network, told CBC News that experts don'tlike to place their trust in figures provided by either Russia or Ukraine.

"Each side has an incentive to inflate the damage they do, and deflate the damage that's been done to them," he said. "It's part of every war to do that."

Experts from the U.S. and NATO use models to calculate losses that are informed by intelligence on the ground, satellite imagery and awareness of the Russian military, making them the most trustworthy sources we'relikely to get, said Saideman and Dorn.

"We know the size of a Russian battalion, we know how many guys go into a Russian tank, which tank takes four, which tank takes three, and we have plenty of video and pictures," Saideman said.

Sean Maloney isa professor of military history at the Royal Military College who served as the Canadian army's historian for the conflict in Afghanistan. He told CBC that, based on his knowledge of Russia's military andsources inside of Belarus and Russia,the high-end NATO estimate of Russian casualties is likely accurate.

"I am confident, with the sources that I have, that the number of Russians killed in action is above 15,000," Maloney said.

Why have so many Russian soldiers been killed so soon?

If that estimate is accurate,it raises a question: Why has a single month of war in Ukraine killed almost as many Russian soldiers as did the Soviet Union'sdecade-longwar in Afghanistan?

"This was always going to be bloodier than the wars that we've become accustomed to because it's just a higher level of explosive power meeting a higher level of explosive power," Saideman said.

Experts say Western democracies have come to expectcasualty numbers similar to those generated by U.S. conflicts in the Middle East. Saideman and Maloney saidthis is a very different kind of war.

Afghanistan and Iraq have been "low-intensity conflicts," Maloney said.

"Yes they are violent, yes people get killed," he said. "But [in Ukraine]we are dealing with high-intensity, mechanized warfare where you have large numbers of vehicles, large numbers of personnel, lots of air support colliding at the same time, all over the place. This is continual, across the board."

Another reason for the large number of casualties, said Saideman, is poor Russian strategy.

"The Russians did not prepare the battlefieldat all," he said. "They did not do many of the things that America/NATO doctrine would usually do, which is to take as much of the anti-aircraft ability away, hit the command nodes.

"The fact that Ukrainians still have power, they still have the Internet, they still have communications means it's a lot easier for the Ukrainians to make smart decisions and communicate them effectively."

Saideman said Russia's military medical serviceshave been substandardas well, which has contributed to the fatality rate. Reports out of Ukraine suggestRussian medics are not properly treating casesof frostbite, along withmore serious injuries.

And because there was no pre-invasion bombardment, he said, airspace over Ukraine remains contested. Ukrainian forces have been able to shoot down helicopters that may have been carryingwounded soldiers back from the front.

Maloney said the poor state of the Russian military has left troops on the ground with inadequateequipment.

"They don't care about their personnel, their vehicles are not equipped to protect their people. They are not like our vehicles with fire suppression systems and all that," he said.

"I have not seen an armoured ambulance this entire war. We have thembut I haven't seen an armoured ambulance at all."

Can Russia take these losses for much longer?

To sustain theseheavy losses and continue the war,Russian President Vladimir Putin mustmaintain battlefield morale and hold on to the autocratic regime he leads. Experts say there are reasons tobelieve both Russia's ability to prosecute the war and Putin's grip on power could beunder threat.

Maloney said Russia's military is poorly trained. He saidthatan estimated 31 senior Russian military officers, from colonels to generals, have been killed in action, as have manyhighly trained soldiers.

Losing officers and experienced fighters can underminetroop morale. But poor training, lacklustre logistics and substandard medical support are having a bigger effect on Russia's war effort, experts said.

"The soldiers who are currently fighting, if they see that their colleagues are not being acknowledged they will lose their will to fight," Dorn said. "If they see their dead comrades, whom they're bereaved about are not being returned home it's going to have a huge effect on Russian troop morale."

Despite his iron grip on Russia, Putin also has to keep in mind the threat of a backlashat home.

"His power base is the intelligence and the military and if he loses the support of the generals and the foot soldiers, then he knows he can't stay in power very long. There's a huge risk for him," said Dorn.

Retired majorMichael Boire, a former NATO war planner and assistant professor of military history at Royal Military College, disagreed. He said that while a high death toll would be a problem forcountry like Canada, Russians are used to bad news.

"A democracy would say these are high, unacceptable, grislynumbers. The average Russian would say, 'That's war, that's the way it is, that's the way you do business,' Boire said.

"The average Russian, he or she expects life to be rough."

Saideman said that during the Soviet war inAfghanistan, a group of mothers organizedto press the regime to end the war and bring their sons home. In the short term, he said, battlefield losses in Ukraine will require Putin to spend more resources to hold on to power. In the longer term, he added,it could go one of two ways.

"At some point there will be a large gathering of people and the Russian oppression apparatus will show up and they'll face a choice of whether to shoot at these protesters or not," he said. "And we never know how that will play out until it actually plays out."

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