Its Latin name comes from the words netta, the Ancient Greek for duck, and peposaca, a transcription of the bird's Guaraní name, which means "showy wings".

Netta species have a bright white stripe on their remiges which becomes visible in flight; Lake duck (Oxyura vittata); Chimango caracara (Milvago chimango), a bird of prey similar to the Peregrine falcon, known locally as the tiuque; buff-necked ibis (Theristicus caudatus), also known as the white-throated ibis or bandurria; Andean condor; ringed kingfisher (Megaceryle torquata), found in wooded areas; Magellanic woodpecker (Campephilus magellanicus), also found in wooded areas.

Mammal species found in the park include the cougar (Puma concolor), coypu (Myocastor coypus, river rat or nutria),[6] the South American gray fox (Lycalopex griseus), the kodkod or güiña (Leopardus guigna).

[7] In wooded areas, the rare pudú (Pudu puda), a small deer, can be found as well as the monito del monte (Dromiciops gliroides), Spanish for "little bush monkey".

Also called chumaihuén in Mapudungun, the monito del monte is a diminutive marsupial endemic to southwestern South America.