I have 2 cats (mother and daughter) that we adopted a year ago. The mother is estimated to be about 2 years old and the daughter is now 1 year old.

They’ve lived in our house peacefully together for a year. Always cuddles together. The last 2 days however the mother cat is now hissing and growling at the daughter and running away from her. And this morning we noticed the daughter cat has scratches on her face.

What could be causing this? Any suggestions on ways to remedy this sudden aggressive behaviour?