What Comes Once, Twice and Never

Can you name the four days of the week that begin with letter "T"

What five-letter word becomes shorter if you add two letters to it?

I am brown. I have a mane.

I like to eat zebras. I roar.

Who I am?

I am big and blue. I am a Mammal.

I live in the ocean. I can swim.

Who I am?

I am made of milk. You keep me in the fridge.

I am cold and you like to eat me in the summer.

Who am I?