Your undergrad degree program is likely to be (and should be) broader, but that doesn’t mean you can’t build a specialty for yourself within that.
One way to research the possibilities is to look for specific faculty members whose research would interest you. You can consider actually contacting them for advice, but even if you don’t, you can learn a lot by looking at their connections - labs, grad students, research partnerships outside the particular school, interest groups that they advise, and so on.
For example, the chair of the Zoology department at Cal Poly Humboldt is a herpetologist: Sharyn Marks Ph.D. | Cal Poly Humboldt
This prof at Whitman College (in eastern WA) talks about education pathways in this field, in the video that this page links to: Kate Jackson | Whitman College (Whitman offers merit pre-reads, which can help with assessing affordability if the school might be of interest. Their Semester In The West program is particularly cool and might be sufficiently adjacent to your interests to be worth a look.)
Those are just a couple of examples; searching the websites of other schools of interest will likely turn up more.