What's the right punctuation for the following list?

Many cases of animal suicide were discused. A duck drowned itself after the death of its companion. A school of dolphins stranded on a beach with no reason whatsoever. A deer threw itself from a cliff to avoid being eaten by hunting dogs. And the list went on and on.

Should I use comma, semicolon, or just leave it as it is? If I chose the semicolon, where should it start?

Write what sounds natural. I like changing the verbs and joining with commas:

There were many cases of animal suicide in the paper: a duck drowning itself after the death of its companion, a school of dolphins beaching itself for no apparent reason, a deer throwing itself from a cliff to avoid being eaten by hunting dogs. The list went on and on.

I wouldn't use commas, since each incident listed is in a complete sentence. But you want to group them together to show that it is a list, so semi-colons is the best solution.

There were many cases of animal suicide in the paper. A duck drowned itself after the death of its companion; a school of dolphins [was] stranded on a beach with no reason whatsoever; a deer threw itself from a cliff to avoid being eaten by hunting dogs. And the list went on and on.