I didn't realize you had a choice. I guess you're just being sarcastic.

Do I have to be reborn?

a mosquito

I'd say an eagle or falcon. It looks like fun to fly around in the sky.

A humpback whale..

Yeah, somebody already said it, but me again. Specifically for me, I spent a good deal of my life really religious. Those years feel pretty wasted to me. But if I'm going to do it again, I want prior knowledge. I don't need to make these mistakes over again.

I guess some kind of bird. The ability to fly would be amazing.

A saltwater crocodile , in the Northern territory of Australia.

Wise, long lived, very tough, and if the opportunity presents - I'd get to munch on a juicy human every now and then, doing my part to help control overpopulation.

Well since I've dreamt of past lives..I was a wolf...multiple times...a crow...a witch or woman accused of witchcraft..a few times that I dreamt of ..one hung..the other burned at the stake...I was a solider in the civil war..I was a tribeswoman in Africa...I was also on the Titanic..died drowning ...

Good question, but so many possibilities! I'd like to be someone or something that sees a lot of the natural world like a migrating animal - bird, whale, sea turtle, penguin or maybe an astronaut. lol
Oh the beautiful sights they would see.

As a priest. Then I can have sex with all the young boys. (The first part is correct, the second was only a joke!)

Anthony Bourdain. Where do I get a job like that. Damn.

A well-loved, well-kept Shiba Inu...

If I was reincarnated I would like to be reborn as someone with power and money to enable me to make our society a better place for all people in which to live.

My answers depend upon whether or not I could remember the experiences of my previous lifetimes. It would be interesting to know how an insect perceives its world; how a bee sees with its compound eyes and its ocelli eyes.
How does it feel to be a snake? An octopus or a squid? Would it really be fun to be a dolphin?
Coming back as a human, I would like to be a little bit taller than I am now, and not prone to being overweight. Also I would not develop diabetes or any other such incurable disease.

a shark, or some other marine animal.

A well looked after cat in a well to do home with a large back yard and no kids to pull my tail

Reincarnation happens, one set of life experiences influences the next. We are always learning, or not!

I would wish to come back as an emperor penguin

an enlightened Human

Tardigrade

I like being human. So being human again in a different setting would be fine