No, bearded dragons can’t eat black beans as they can’t digest grains.
Black beans contain starch and sugar that cause digestive problems for beardies. Not to mention they are very low in calcium which is bad for growing beardie lizards.
So you should avoid giving them to your beardie.
What if my beardie eats black beans?
If your beardie accidentally eats a few black beans they shouldn’t get sick, but if they eat a whole bunch of them it can cause digestive issues.
If your bearded dragon is eating black beans regularly it’s time to make some changes!
Try cutting out the grains/starches from the diet. The bearded dragon should start feeling better once the beans are out of the diet.