It is threads like this that gives religious people a bad name.
Its lack of understanding and thus quickness in attacking others without reason, that gives non religious people a bad name.
What has been clarifed in this thread is that if a person wishes to be reunited with his/her pet in the hereafter, then he/she will It is Jannat (Heaven) we are talking about after all.
If a person had a pet 'dolpin, crocodile..or whatever you listed, then fine , he/she can have the with him/her in Heaven. If a person wants the company of a certain type of bird or any other species with him/her i Heaven, then it is also very possible.
Animals in this life were not created to be tested by Allah swt which is why they turn to dust not brought up for reckoning like humans. HOWEVER, as some are our companions, ie pets, Allah swt, Most Merciful, All -Capable, can and will grant us their company if we ask for it, in addition to filling Heaven with various species that He, Himself has chosen. (see the Quranic description of Paradise for details ).