Did you read the article?
“Now, dolphins may join that list. Footage from a new BBC documentary series, “Spy in the Pod,” reveals what appears to be dolphins getting high off of pufferfish. Pufferfish produce a potent defensive chemical, which they eject when threatened. In small enough doses, however, the toxin seems to induce “a trance-like state” in dolphins that come into contact with it.”
Did they test the dolphins to see if they were getting high?
They just “assume” they are trying to get high, rather than being too stupid to avoid the toxic puffer fish.