Did you know? Dolphins

We have learnt that  dolphins are mammals, so they are born live and they feed their babies with their mother's milk.
I have a question, do they breathe through gills or do they breathe with lungs?


Here you can see a baby dolphin inside its mother:

Now you can see the dolphin giving birth:

And here you can see the mother feeding its baby:

Can you see these two lines? They are the place where they have their milk. 
They are not similar to human breasts!

Remember that the same happens to whales!