I'm not clear on the difference between the use of -ipi / wepi here and the what the meaning would be with 'gani'. I assumed the use of -ipi would have the meaning "which animals" rather than "what kind".
Nowadays, the differentiation between "gani" and "-pi" is not as strict anymore.
Please note the explanation "Forms for WHICH?" in the tips and notes section for the skill "advanced/additional grammar".
There is also a tabular overview with prefixes for each noun class to be applied for "-pi".