% learned.
class(A,reptile, 1) :-
	has_legs(A,4), has_eggs(A).
class(A,mammal, 2) :-
	has_milk(A).
class(A,fish, 3) :- 
	has_gills(A).
class(A,reptile, 4) :-
	has_legs(A,0), habitat(A,land).
class(A,bird, 5) :-
	has_covering(A,feathers).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Types

animal(dog).  animal(dolphin).  animal(platypus).  animal(bat).
animal(trout).  animal(herring).  animal(shark). animal(eel).
animal(lizard).  animal(crocodile).  animal(t_rex).  animal(turtle).
animal(snake).  animal(eagle).  animal(ostrich).  animal(penguin).
animal(cat).
animal(dragon).

animal(girl).
animal(boy).


class(mammal).  class(fish).  class(reptile).  class(bird).

covering(hair).  covering(none).  covering(scales).  covering(feathers).

habitat(land).  habitat(water).  habitat(air).  habitat(caves).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Background knowledge

has_covering(dog,hair).
has_covering(dolphin,none).
has_covering(platypus,hair).
has_covering(bat,hair).
has_covering(trout,scales).
has_covering(herring,scales).
has_covering(shark,none).
has_covering(eel,none).
has_covering(lizard,scales).
has_covering(crocodile,scales).
has_covering(t_rex,scales).
has_covering(snake,scales).
has_covering(turtle,scales).
has_covering(eagle,feathers).
has_covering(ostrich,feathers).
has_covering(penguin,feathers).

has_legs(dog,4).
has_legs(dolphin,0).
has_legs(platypus,2).
has_legs(bat,2).
has_legs(trout,0).
has_legs(herring,0).
has_legs(shark,0).
has_legs(eel,0).
has_legs(lizard,4).
has_legs(crocodile,4).
has_legs(t_rex,4).
has_legs(snake,0).
has_legs(turtle,4).
has_legs(eagle,2).
has_legs(ostrich,2).
has_legs(penguin,2).

has_milk(dog).
has_milk(dolphin).
has_milk(bat).
has_milk(platypus).
has_milk(cat).


homeothermic(dog).
homeothermic(dolphin).
homeothermic(platypus).
homeothermic(bat).
homeothermic(eagle).
homeothermic(ostrich).
homeothermic(penguin).
homeothermic(cat).


habitat(dog,land).
habitat(dolphin,water).
habitat(platypus,water).
habitat(bat,air).
habitat(bat,caves).
habitat(trout,water).
habitat(herring,water).
habitat(shark,water).
habitat(eel,water).
habitat(lizard,land).
habitat(crocodile,water).
habitat(crocodile,land).
habitat(t_rex,land).
habitat(snake,land).
habitat(turtle,water).
habitat(eagle,air).
habitat(eagle,land).
habitat(ostrich,land).
habitat(penguin,water).

has_eggs(platypus).
has_eggs(trout).
has_eggs(herring).
has_eggs(shark).
has_eggs(eel).
has_eggs(lizard).
has_eggs(crocodile).
has_eggs(t_rex).
has_eggs(snake).
has_eggs(turtle).
has_eggs(eagle).
has_eggs(ostrich).
has_eggs(penguin).

has_gills(trout).
has_gills(herring).
has_gills(shark).
has_gills(eel).

nhas_gills(X) :- animal(X), not(has_gills(X)).