Complex sentence: Granny, also known as J2, was an orca, or killer whale, estimated by some whale researchers to be 105 years old, which, if correct, would make her the oldest known living orca, at the time of her death.
Split into simpler sentences: Granny, also known as J2, was an orca, or killer whale, estimated by some whale researchers to have been 105 years old. If correct, this age would make her the oldest known living orca at the time of her death.