On a magical land of Narnia , all the animal in the land are rational.

There are 10 tigers and one goat.

Tiger can eat goat but since its a magical land , the tiger who eats the goat , turns into goat and then can be eaten by the remaining tiger(s).

If we leave them for some time then how many goat and tiger will be there , when we come back ?

9 tiger and one goat

since all animal are rational , once 1st tiger eats the sheep all the rest of tiger would know about this.