He may be man's best friend, but Jack the black lab is also a hero to other pooches.
He is one of about a dozen canine blood donors in the London area and like human blood donors, they can be life-savers.
Jack pays routine visits to the London Regional Veterinary Emergency and Referral Hospital, usually every two to three months, and gives a pint of blood at each visit.
According to Erin Long, director of the donation program, he also has the ideal blood to help other ailing canines.
"There's two different types that we test for. There's A-positive and A-negative. A-negative is the universal donor, which Jack is, and then there's A-positive dogs that can only donate to A-positive dogs. So, A-negative dogs can donate to both, so they're the ideal donor."
Jack's owner Dave Forster says when he heard the clinic was looking for donors, he knew stepping up was the right thing to do.
"Just to save dogs. We go out of our way to save dogs all the way and this is no strain on him or me. Erin calls and we're usually here within 15 minutes and we do what it takes."
And while many dogs seem to dread making a trip to the veterinarian, Jack has no problem with giving blood.
"The dogs usually don't mind the donation at all. Sometimes we'll do nail trims and stuff afterwards and they hate that a lot more than the actual donation itself," Long says.
Long adds that to the best of her knowledge, the clinic is the only one locally that has a blood bank. They actually share their blood with other clinics around the city and each donation can help up to two dogs.
Like human donations, the blood is separated into red blood cells and plasma, and Long says many dogs have been saved thanks donors like Jack.
Forster says "My wife calls him the hero, Super Jack."
There are currently 13 donor dogs in the program in London, which seems to meet the current need.
Along with having the right blood type, donor dogs have to be between one and six years old, so Jack will be making donations for a few more years to come.