Canid hybrids are the result of interbreeding between two different members of the canine (dog) family (Canidae).
The wolf (including the dingo), coyote, jackal, and domestic dog all have 78 chromosomes arranged in 39 pairs.
This allows them to hybridise freely (barring size or behavioural constraints) and produce fertile offspring.
The wolf, coyote, and golden jackal diverged around 3 to 4 million years ago.
Other members of the dog family diverged 7 to 10 million years ago and are less closely related and cannot hybridise with the wolf-like canids: the yellow Jackal has 74 chromosomes, the red fox has 38 chromosomes, the raccoon dog has 42 chromosomes, and the Fennec fox has 64 chromosomes.
Although the African Wild Dog has 78 chromosomes, it is considered distinct enough to be placed in its own genus.