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There's nothing that says Pokemon share lifespans with that of normal animals WITH THE EXCEPTION of Bug Type Pokemon, in Adventures, Venemoth's dex entry explicitly mentions it has a short lifespan, and irc, the JP version of the Bye Bye Butterfree episode implied they were gonna mate then die, or something like that.
But that was the canon 20 years ago, and stuff not from the games no less, so it's likely different now. Most Pokemon at the very least far outlive that of their animal counterparts if we look at that Emboar card set showing him growing up with that family. It'd be hard to get invested in these monsters if they only lived like 2 or 3 years anyway.
