The dog, identified in media reports as Simba, was travelling in the cargo hold of a flight bound to Toronto from Tel Aviv.
En route, however, the unidentified pilot got an indicator that one of the heaters in the cargo hold had malfunctioned.
Air Canada rules state that minimum ambient temperatures need to be at a minimum of 10 degrees when dealing with canine travellers.
Air Canada spokesman Peter Fitzpatrick says the pilot recognized that the cargo hold would soon be far colder than that as the plane flew over the Atlantic Ocean and realized that the dog might not survive.
Fitzpatrick says the pilot diverted the plane to Frankfurt, transferred the dog to another plane, and made it to Toronto only 75 minutes behind schedule.
"While we recognize this was an inconvenience for our customers, the overall reaction was positive, particularly once people understood the dog was in potential danger but safe as a result of the diversion," Fitzpatrick said in an email.
Dog and owner were reunited at Pearson International Airport, where the unnamed dog lover told a local TV station that Simba was like his child.
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