dog-years
Explanation
The Joke
A couple is celebrating their dog's birthday. The woman announces: "Congratulations! You're 120 years old in dog years!" (meaning the dog is roughly 17 in human years, using the common "1 human year = 7 dog years" conversion). The woman then has a sudden realization: "Wait, does that mean he has 120-year-old political views?"
The final panel shows the dog thinking to itself with a thought bubble containing an old-fashioned, reactionary sentiment: "Why does the man make the cake and not his woman?" -- confirming the woman's fear that a creature with the equivalent age of someone born in 1900 would indeed hold correspondingly antiquated views about gender roles.
The Humor
The joke takes the familiar concept of "dog years" -- normally used as a lighthearted way to anthropomorphize a pet's age -- and follows it to an unexpected logical conclusion. If a dog is truly "120 years old," then its worldview should match that of a person born in the early 1900s, complete with outdated social attitudes. The dog's thought about why the man is baking instead of the woman is a perfect encapsulation of early-20th-century gender expectations, delivered as a deadpan inner monologue. The comedy works because it takes an innocent birthday celebration and reveals the horrifying implication that your beloved pet, if it could think, would be a reactionary from the Edwardian era.