I am in need of a band logo to use for my band, on promotional
material, tshirts, the website etc. I have found a photograph of an
animal on a website which i like. There is no mention of copyright or
any other details bar the pictures on the site. I have used photoshop
and turned the picture into a greyscale cartoon style drawing (so it
looks like a clipart). Am i able to use this for my band, as it is not
the original photo, the only thing remaining is the outline shape.

If it is recognizable by the original photographer then it is
copyright infringement. Did you try to contact the web site owner and
ask permission to use it? If you send the photoshop image you made
along with the original image and explain what you did, you will
probably get the green lite, as long as it's a personal (not
commercial) web site.

A few things to keep in mind:

Copyright generally attaches the moment a work is created. Neither
formal registration nor identification of copyright holder generally
required. (At least for most works created in the past few decades or
so.)  Therefore, the fact that the image you found had "no mention of
copyright or any other details" should certainly not be taken as
evidence that there is no copyright at all.

Also, copyright includes not only rights over the work itself, but
also to works derivative from that work. It is certainly theoretically
possible that the copyright holder of the image you are using
would/could claim that your photoshopped image is derivative of the
original and therefore subject to the orginal owner's copyright.

A reality is that it's certainly possible that if there is a copyright
holder, he/she/it/they may never notice your usage and you'll be able
to use your version just fine. But that's a different question then
whether or not your usage is legally permissible in the first place...