Eliza is on drugs.
The Wild Thornberrys follows a family as they travel the world to film their father’s nature show, but it mostly focused on the youngest daughter, Eliza, who was granted the ability to talk to animals by a magical shaman.
It seems like a perfectly normal concept for a cartoon, but here’s where things get a bit questionable.
Nobody else in Eliza’s family ever sees any evidence of this power, and throughout the rest of the show, they never encounter anything overtly magical or supernatural again.
The only explanation is that Eliza can’t really talk to animals.
She just received a hallucinogenic drug from the native that makes her think she can.
This drug, like acid, just stays in Eliza’s system throughout the show and eventually led to an appendix infection that almost killed her in the third season.