The border collie that knew more than 200 object names and inspired later language studies was Rico.
Rico became famous after his owners reported that he could retrieve toys and other objects when they were named. Animal psychologist Juliane Kaminski and colleagues at the Max Planck Institute for Evolutionary Anthropology tested those claims under controlled conditions designed to prevent unconscious cues from the owner.
Rico correctly retrieved an average of 37 out of 40 requested items. He also appeared able to learn a new object's name after a single exposure by using “fast mapping”: when one unfamiliar object was placed among several familiar ones, he inferred that the unfamiliar word referred to the unfamiliar object. He could still remember some object names weeks after exposure.
The story is often confused with Betsy or Chaser, other exceptionally capable border collies. Betsy was reported to understand more than 300 words, while Chaser later demonstrated a vocabulary of 1,022 object names. Rico's importance was different: his controlled experiments provided influential evidence that a dog could use exclusion to infer a new word's meaning.