Any name will do but it makes sense to give it a descriptive name so you know what set of elements you are referring to/pulling the data from. I.e. Maybe you had a second set of check boxes on the page that referred to the animals ‘appearance’. It would get confusing if you just instead called these ‘animal1’ and ‘animal2’.
Using a descriptive name allows reference in the DOM and helps keep the code clear/easy to read understand. However there are no ‘special properties’ of names, that is ‘personality’ here is not a function or represents anything ‘special’. You could just as well use ‘attitude’ for the name.