According to local lore, the Scotland Island Dog Race started as a friendly rivalry between two ferry captains. But the 45th annual race this Christmas Eve will be a rivalry for the ages: dog versus cat.

Gus, an 11-month-old Tonkinese cat, is planning to join about 70 dogs in the 2019 event, swimming the 550-metre stretch between Scotland Island and Church Point Wharf on Sydney’s northern beaches for the prize of dog food and a beer.

The cat's out of the bag about Gus's participation in the dog race. Credit:Alec Smart

Gus's owner, so-called political "preference whisperer" Glenn Druery, says Gus is "just like a dog". Gus joins Mr Druery on jogs and swims, and enjoys mountain biking and kayaking.

"I put the kayak in off the dock, he jumps in the kayak and away we go," he said.