Jargon “horse” in a Southern Cal. Native language?

Why would the Chinook Jargon word for “horse” turn up quite early in Southern California?

horse los angeles

Horatio Hale’s 1846 “Ethnography” volume of the US Exploring Expedition, page 566, has “keutan” for horse in the Netela/Kij language of the  San Juan Capistrano area, south of Los Angeles, CA.

“Horse” is the Spanish loan kaavaay in the very closely related and nearby Jamul Tiipaay (Kumeyaay) language.

Hale had an excellent ear and mind for language, so I’m uninclined to see his “keutan” is a mistake.  My recollection of Bill Bright’s “Animals of Acculturation in California Native Languages” is that the CJ word turns up in only a couple of Northern CA languages.

What a mystery!