On a small island alone there are many things you should take.

A water filter, flint and steel, and other basic necessities.

And sure that is all good and well but another thing that is important 

Is something we all crave on a daily basis, some less than others of course

Companionship.

Now being trained to survive outdoors I never leave home without a water filter

but another killer in the wild is loneliness.

Humans crave attention is in our nature.

To love, hate, and form all sorts of bonds with our fellow humans.

But I would not take a human as my one thing.

I would take the my cat.

Bigboy has been with me since I was 5

a solid friend to laugh, cry and talk too.

For 10 years my boy and I have been 

together.

I think I would be selfish enough to take him with me

Ignoring all my training on how to survive.

My cat Bigboy would be the one "thing" 

I took with me on an abondon island.