Dogs and cats share some of the same health issues, but then again, some illnesses are completely unique to the species.
Felines and canines are both carnivores (meat eaters), but with a very important distinction. Cats are obligate carnivores, whereas dogs are scavenging carnivores.
Dogs pant to cool themselves off, and cats can, too, but we don't see it as often because cats have other cooling mechanisms.
Dogs are pack animals, and as such are highly social animals who are more easily trained, while cats might hunt mice, but not on command; it's more of an instinct.
One interesting aspect of a cat's palate is that they're not able to detect sweetness, while dogs can.
Human prescription drugs may not adversely affect dogs the way they do cats, in sometimes scary ways. (But be sure to keep medications stored safely away from both dogs and cats.)
Both dogs and cats are scavengers, but dogs are better at it. Cats typically hunt to kill, with less focus on scavenging.
One physical difference between domestic cats and dogs is that cats are prone to hepatic lipidosis, or fatty liver disease, while dogs are not.
You generally know what dogs want — they want a treat! But cats need a little more inspiration.