Here's a breakdown of why:
* Chordata: The phylum that includes all vertebrates, as well as some invertebrates.
* Vertebrata: The subphylum that includes all animals with a backbone, which includes pugs.
* Mammalia: The class that includes pugs, characterized by having mammary glands, fur, and giving birth to live young.
* Carnivora: The order that includes pugs, characterized by having sharp teeth for tearing flesh.
* Canidae: The family that includes pugs, characterized by having long snouts and a bushy tail.
* Canis: The genus that includes pugs, with the scientific name *Canis familiaris*.
So, while pugs are familiar pets, they're also part of a long and diverse lineage of animals that includes all the way back to the very first vertebrates.