When Ward looks up the telephone number for the zoo, it's KLondike 5-2342. Since the early 1970s there has been at least one 555 number callers can dial and get an answer-555-1212 is a standard number that rings directory assistance. The rest of the 555 numbers have largely gained fame as fake numbers in movies and on TV. Telephone exchange names were phased out in the 60's.
The title is based on the play Three Men on a Horse which opened on Broadway in New York City, New York, USA at the Playhouse Theater on 30 January 1935 and closed on 9 January 1937 after 835 performances.