the question is not whether they are exotic (invasives are ONLY exotic animals and plants) but the question is what species do people (also an invasive species) favour keeping as a pet: animals that are more likely to be invasive or not invasive? so yes, dogs and cats — both exotic species — ARE invasive pests, as are most of the pets that people typically keep. (note that invasives are HARMFUL to species living in their new environment, or to the environment itself, so not all animals that have been introduced and live outside their natural range are considered to be “invasives”. but if you’d read the piece, you would already know this.)