In the mid 1920's, the Crosley Radio Company of America produced a very small, single valve radio receiver.  Owing to its size, they named it the Pup.  When they came to advertise this radio, they naturally used the image of a dog to do so - in much the same way as His Master's Voice had done with the image of Nipper looking into a gramophone.  The advert showed a small terrier-like dog sitting next to a Crosley Pup wearing headphones - the main way of listening to the radio.
Quite how this image came to be altered, and Bonzo became used as their three-dimensional promotional figure is unclear.  However soon after its release, the Old King Cole Inc. company of Canton, Ohio were commissioned to produce large papier mâché figures of Bonzo sitting with his front paws supporting him and wearing a pair of headphones.  Embossed into the headphone band on his head was "Crosley Pup".  He is an impressive 9 inches tall and 8 inches long.

The Store Display Model

The manufacturers paper label that was placed inside the model, near its hollow base.


 
 

The 'Domesticated' Pup

Crosleys also had made many smaller 'pups' from a chalk composite, which just had the word "Crosley" incised on the headband.  These were made to sell for $1 to meet the demand from customers in the radio shops who wanted to buy the larger store display piece for themselves.  This chap is 4½ inches tall and 5½ long.


 
If anybody can help in shedding more light on this connection between Bonzo and Crosley, please let me know and I'll be happy to use the information to update this page.