This probably isn't new behavior, simply something we're witnessing for the very first time.
We haven't observed orcas predate moose or primates, but the former has plenty of supporting evidence and the latter has probably happened at some point.
In any case, zoonotic reservoirs likely slosh around a lot more than we think before spillover events.
I agree. This has probably been happening for millions of years. Bats often live in dense colonies in caves and tree trunks with small exits making rat predation possible.
Some native Arctic peoples have traditions of killer whales eating people, although officially they have only killed people while in captivity. A person in a skin kayak would be easy prey for one.
We haven't observed orcas predate moose or primates, but the former has plenty of supporting evidence and the latter has probably happened at some point.
In any case, zoonotic reservoirs likely slosh around a lot more than we think before spillover events.