Cross-sucking, or non-nutritive sucking on the bodies of littermates, is commonly observed in early-weaned animals. This behavior has been well-documented in production animals, which are often separated from their mothers before weaning. The behavior is less well-understood in other domestic species, such as cats (Felis catus), that can be orphaned due to neglect, maternal death, or accidental separation. Anecdotally, cross-sucking can cause injuries in kittens, sometimes severe enough to warrant euthanasia. To our knowledge, this is the first detailed study of this behavior in domestic cats. We conducted a survey of caretakers (N = 407) of kittens (< 60 days old) with the goal of identifying characteristics of individual kittens, litters, the environment, and husbandry that might be associated with the presence of cross-sucking. The final data set, representing 1358 kittens, was comprised of 301 litters experiencing sucking and 106 litters not experiencing sucking behaviors. Almost all of the kittens represented in the survey (91%) were orphaned. Results suggested that being orphaned (X 2(1) = 42.64, p < 0.001), bottle-fed (X 2(2) = 40.32, p < 0.001), younger (t(405) = 3.48 p < 0.001), separated earlier from the mother (t(376) = 3.10, p = 0.002), and being in an all-male litter (X 2(2) = 7.13, p = 0.03) increased the risks of cross-sucking. Male kittens also were more likely to be recipients of sucking behavior (X 2(1) = 32.30, p < 0.001). No clear associations between the environment or husbandry practices and the presence of sucking behavior were identified. Interruption and separation were the most frequently reported management strategies, but most kittens returned to sucking behavior when reunited. Cross-sucking is a frequently reported behavior problem in orphaned kittens that may indicate distress or poor welfare. Future research should focus on a better understanding of prevention and management strategies, and determination of the effects, if any, of cross-sucking as a kitten on adult cat outcomes or behavior.
Keywords: domestic cats; maternal separation; neonatal development; stereotypies.