As it turns out, you can teach an old dog new tricks.

A fierce Fido had a change of heart after being abandoned by Russian forces, teaming up with Ukrainian soldiers in the ongoing war that began on Feb. 24.

The 3-year-old Belgian Malinois named Max was once starved by the Russians and found nearly dead by Ukrainians who took him to safety. Before his discovery, Max was surviving off of leftover scraps on the ground while wandering in the forest wearing a Russian military collar.

“We can’t understand why the Russians would leave behind such a lovely animal,” one soldier said, according to Pets Radar.

After nursing him to full health, his new family enrolled him in combat training, teaching him to sniff out mines and even some Ukrainian commands.

“From now on, the Mykolaiv National Guards have a trophy dog with the nickname ‘Max,’ ” said a post on the military unit’s official Facebook page. “The shepherd belonged to the occupiers of the Rosgvardíí жа, who captured one of the villages of the Nikolaev region.”

“From now on, Max will serve on the right side and defend Ukraine,” it continued.

“They are tremendously loyal but Max has obviously been ­convinced that the Ukrainians are now his new masters,” a British special forces soldier said.

Since the canine is so clever, he’s beginning to work with the Ukrainian National Guard. He joins the ranks of fellow military mutt Patron, a Jack Russell terrier that won a medal of honor for saving lives by sniffing out explosives.

“The main tasks are to check citizens on checkpoints and search for saboteurs,” one soldier told Triangle News, adding that Max will also learn to find people, not just bombs. “The dogs of this breed, namely ‘Belgian Shepherd’, have a very good, almost perfect memory.”