Is a Mahayana Buddhist *required* to take a Bodhisattva vow?

Is the taking of a Bodhisattva vow a *requirement*(1) in Mahayana, or is it merely an *option* (or maybe at most a recommendation)? And if it's not a requirement, then for someone who decides not to take it, what if anything is the difference, in terms of the overall aim(2), between the Mahayana approach and the Theravada approach? -- (1) By "requirement" I'm invoking the usual idiomatic use of that word -- i.e. pointing to an action and its consequences. For example, "if you want to build muscle, you are required to lift weights" or "if you want to avoid rebirth in a hell realm you are required to refrain from murdering your parents" (2) Clearly there are differences in practice formats, but I'm thinking more of the end point. In that context, without the vow to continue as a Bodhisattva, Theravada and Mahayana seem like one and the same.