I have 2 corn snakes one about 16 months old and one about 5 months old. They both live happily together in a large viv and have done for a few months. About 3-4 weeks ago the older snake became aggressive up until then we have been able to take her out and handle her, but since about 3 weeks ago everytime we go near her she strikes, quite viciously, constricting round my hand too. I take her out of the tank to feed her and I've increased her feeds incase that was the problem but its not helping. The older snake is female and we're not sure but think the younger one is male.