To which ancient mammalian order do echidnas belong?
Answer
Monotremes
Echidnas belong to the order of monotremes, which represents an ancient lineage that also includes the platypus.

Related Questions
To which ancient mammalian order do echidnas belong?Where are echidnas unequivocally endemic?What constitutes the primary diet for echidnas?What is the status of established wild, self-sustaining echidna populations in the United States?What are the two genera that encompass all recognized echidna species?What primary factor besides climate makes natural colonization of echidnas in North America improbable?For which purpose are echidnas housed in accredited US zoos?Where are the geographically constrained long-beaked echidnas (*Zaglossus*) found?What practice involving international trade sometimes involves the short-beaked echidna being moved illicitly?Which regions comprise the broader distribution range of the short-beaked echidna (*Tachyglossus*)?