A fluid absorbent assembly includes a fluid absorbent material located in an animal cage or in a liner inserted into the cage. The fluid absorbent material may comprise or be combined with a material that absorbs or neutralizes noxious vapors. A fluid permeable animal support structure may be located over the fluid absorbent material. The fluid absorbent material, which may be contained in a pad, may be contained in a housing that also forms the animal support structure. In the event of a drinking valve leak or other fluid leak within the cage, the fluid absorbent material expands and raises any animals located within the cage.