The oldest documented living creature on Earth is a Seychelles tortoise named Jonathan, who is reported to be about 183 years old. I spoke to a Mayfly recently, and remarked upon the unfairness of a tortoise living for 183 years and a Mayfly living only one day. He thought for a moment and then said he and the tortoise both lived a lifetime, and so there was no unfairness, either to Jonathan or to him. He went on to say

The tortoise lives for many years
While I a single day
And yet both live so it appears
A lifetime in a way
Now you will live your measured time
And when compared to me
You have a life of treasured time
While I one sun will see
And yet I live a rich full life
To me it seems just right
I’m born and live a life that’s rife
With joy until it’s night
At seventy you up and die
A dog at fifteen’s gone
For  years some birds enjoy the sky
While I am born at dawn
And sunset sees my life at end
And yet I’ll not complain
For all is relative, my friend
For God has, in the main
Seen that our lives are in His care
And whether short or long
It seems to me He’s very fair
And never does us wrong
Yes Jonathan lives many years
And I a single day
But count the joys and count the tears
It’s not how long you stay