alimentary canal vs digestive tube

alimentary canal and digestive tube both are nouns.

Word	Noun	Adjective	Verb	Adverb
alimentary canal	Yes	No	No	No
digestive tube	Yes	No	No	No

As nouns, alimentary canal and digestive tube are synonyms defined as:

alimentary canal and digestive tube: tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination

Other synonyms of alimentary canal include alimentary tract, digestive tract, gastrointestinal tract, GI tract.

alimentary canal (noun)	digestive tube (noun)
tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination	tubular passage of mucous membrane and muscle extending about 8.3 meters from mouth to anus; functions in digestion and elimination