"Artists Beware"

Your example is an example of "work for hire." Large corporations or other entities who want to retain all rights generally A) contractually bind you into the agreement that what you are creating for them belongs to THEM. They generally will give you portfolio rights (or credit) in the process of negotiations. B) PAY FOR THESE RIGHTS. There's a reason logos and the like usually are paid in the quadruple+ digits, to compensate for the loss of artistic rights to the work, on top of services rendered.

A furry with a pink gshep can't pay $10 or less for a piece of art and claim copyright of the body of work.