Biological Ships
Biological Ships in the Stellaris encyclopedia: - Biological ships use specialized combat ship classes with clearly defined roles and three growth stages.
Biological Ships in the game's words
The encyclopedia entry as the game shows it in its tooltips; underlined words open their own entry or page here.
- Biological ships use specialized combat ship classes with clearly defined roles and three growth stages.
- Construction costs primarily use Food instead of Alloys
- Upkeep costs primarily use Food upkeep instead of 
Energy Credits.
- Depend on 
Biology technologies instead of 
Voidcraft technologies.
--------------
Living vessels composed of massive, undulating muscle fibers filled with bioluminescent organelles release energy-rich compounds to produce bursts of light and heat for propulsion.
Source: common/game_concepts (concept_biological_ship, also concept_biological_ships) and localisation/english, Stellaris Cygnus v4.5.2 (9776).