In a world of cats on hot tin roofs, everyone knows how to scratch each other's eyes out...and they do just that. There is never a quiet moment in Cat; characters are always fighting tooth and nail (either with words or crutches) to get exactly what they want.
The word ferocious also makes us think of things like hissing raccoons, hyenas, wolves, and other scary creatures. The characters in this play are often described in stage notes as animals, and Maggie even tells Brick she feels like they share the same cage.
How can such a dog-eat-dog world be a soft world, you ask? What an excellent question. The softness, we feel, comes from the set (which Tennessee Williams describes as possessing a soft light) and the dreamlike setting of the play (suspended in an impossible, pre-Civil War era, detached from the reality of the 1950s), as well as from Brick, Maggie, and Big Daddy's vulnerabilities and desires that spill over when the ferocity of the Pollitt House becomes too powerful.