A bluish tongue color in dogs can indicate a condition called cyanosis — which essentially means there is a shortage of oxygen in the blood.
Not exact matches
Besides its prodigious span, the giraffe
tongue is also marked by its distinct
bluish - black
color.
If your dog's
tongue is
bluish in
color and you are sure that this is not due to eating anything that could transfer this
color (also check toys for transferable dye) then I recommend a thorough veterinary examination to determine if the discoloration is due to cyanosis.