Fecal consistency is routinely used as an indicator of gastrointestinal health and diet suitability in zoo animals. The underlying processes in ungulate fecal consistency are not often investigated. The authors assessed multiple factors on fecal consistency scores in six adult zoo moose (Alces alces) retrospectively for a 3-yr period. All animals were regularly tested for gastrointestinal parasites and received antiparasitics when noted. Neither the provision of dietary browse nor number of visitors had a significant effect. Seasonally varying intake of the staple pelleted diet was the main explanatory factor, with an additional effect from environmental temperature or season. Higher intakes and higher temperatures were linked to less well-formed feces. The authors hypothesize that during the summer hyperphagia to replete body reserves, the water re-absorption function of the large intestine apparently becomes overtaxed. Heat stress may have an additional, intake-independent effect. Although monitoring fecal consistency is a part of good health surveillance, physiologic seasonal effects, as reported here, need to be taken into consideration when interpreting the observations.