Chulo is a Spanish adjective meaning cute, charming, or attractive — used as an informal term of endearment particularly in Mexican and Caribbean Spanish. As a pet name it's affectionate by definition, the kind of thing you say to an animal you find irresistible. Male pets dominate the registry data, which matches the gendered masculine form of the Spanish adjective.
Spanish Affection Culture
Spanish-speaking pet owners often choose names that function simultaneously as names and descriptions — Chico, Bonita, Guapo, Chulo. These names carry their meaning on their sleeve in a way that English pet names often don't. A dog named Chulo is being called charming every time his name is used, which is either excellent reinforcement or entirely too much pressure depending on the dog's actual level of charm. Chihuahuas appear with this name at above-average rates in urban registry data.
The Coati Connection
The coati (coatimundi) is also known as the "chulo" in some Central American Spanish variants — a fun zoological footnote for owners who enjoy that kind of layered reference, though most owners choosing the name are using it in the endearment sense.
Counter-Read
Chulo is culturally specific enough that it requires Spanish-language context to land fully. Outside that context it may be mispronounced or require explanation. For a similar affectionate-Spanish-adjective approach, compare Guapo or browse all pet names in the Spanish-origin register.