Prototherians may significantly impact populations of their prey; this may be more true for echidnas because they specialize on only a few prey types rather than eating a little bit of many different species. Because they are adept diggers, prototherians create and modify habitat for other organisms. Platypuses in particular can exavate extensive burrows on the banks of freshwater lakes and streams. Prototherians are hosts of various parasites (e.g. trypanosomes in platypuses and hepatozoans in echidnas).
Ecosystem Impact: creates habitat