Think Outside the Box to Prevent Going Outside the Box

Inappropriate elimination is a common behavior challenge in cats and a frequent reason for relinquishment or euthanasia. Common control recommendations include increasing the cleanliness and number of litter boxes, removing covers, and changing litter substrates. Antianxiety medications are sometimes prescribed. Despite these interventions, many cats still urinate and defecate outside the litter box.

This study evaluated the response of healthy indoor-only domestic cats to the simultaneous provision of 2 different-sized plastic litter boxes: one 56 × 38 × 14 cm (regular size), the other 86 × 39 × 14 cm. Clumping litter was used as the substrate. Cats (n = 74) from 43 households were included. Owners recorded the daily number of urine and fecal deposits in each box for 1 month. After 2 weeks, box locations were reversed to detect and eliminate location preferences.

In total, 5,031 deposits were noted in the larger boxes and 3,239 in the smaller boxes. Defecation in the smaller boxes was the least frequent event; urination in larger boxes was the most frequent. While individual feline preferences in multicat households were not recorded for practical reasons, no significant association was detected between number of cats in the home and box size preference. Overall, results indicated most cats showed a definite preference for a larger litter box. Practitioners should consider adding this recommendation to those previously listed.

Cats have a desert ancestry where the entire desert was their litter box, so it is not surprising that they prefer large litter boxes. When shopping for litter boxes, even jumbo boxes are only 22–23 inches long—the approximate size of the regular box used in this study. It is important to give owners suggested dimensions rather than asking them to depend on the box manufacturer’s choice of adjective. Owners need to think outside the box when hunting for an appropriate litter-holding container. Under-the-bed storage bins (34 × 16 inches) and cement mixing trays (36 × 24 inches) are 2 items I recommend. If a household cannot accommodate the suggested litter box size, I recommend that owners obtain a box that is at least 1.5–2 times the cat’s length from nose to rump.—Sandra Sawchuk, DVM, MS

LItterbox size preference in domestic cats (Felis catus). Guy NC, Hopson M, Vanderstichel R. J VET BEHAV 9:78-82, 2014.