File into dictionary?

File content:

Dog, cat, zebra

Spider, ant

Shark, seal, whale

I know that I need to open the file and use readlines and also a loop. But I don't know what to do.

EDIT:Sorry for no enough information. I will give another example.

File content:

Jay, Dan, Kim

Margo, Dylan, Lam, Albert

James, Jerry

The first names in each line I want to be the key, while the value would be the remaining names.

Ex. {"Jay": ["Dan", "Kim"]}