Is it possible to legally claim a cat as your child?

Well I know it's a very odd question but I really do consider my cat as my own son, I wouldn't love my human child any more or less. The reason I ask is because he has quite a few health issues and on medication. I work away on a ship all summer long and Im always worrying something will happen while im working and companies don't consider a pet very important which to me is very sad. So im asking if it is possible and how? Please only serious answers, thank you.