Rate of passage of digesta through the alimentary tract of the New Zealandfur seal (Arctocephalus forsteri) and the Australian sea lion (Neophoca cinerea) (Carnivora : Otariidae)

The inert marker titanium dioxide was added to the food of two male New Zea land fur seals (Arctocephalus forsteri) and three Australian sea lions (Neo phoca cinerea) in Taronga Zoo, Sydney, in a series of 15 trials. The enclos ures were checked constantly during daylight hours, and defaecation times a nd location of samples noted. Samples were collected at feeding times, at a pproximately 0930, 1300 and 1500 hours. During the night the animals were c hecked at 30-min intervals, the location of samples noted, and samples coll ected at the first feeding time next morning. Faecal collections were made for up to 50 h after dosing. Marker concentrations in faecal dry matter wer e determined and mean retention times calculated from the mean concentratio n-time curves. The mean time between dosing and first recovery of marker (Initial Recovery Time) was 4 h for A. forsteri and 6.5 h for N. cinerea. Mean retention tim e, a better index of rate of passage of digesta, was 14.6 h for A. forsteri and 14.9 h for N. cinerea. Thus, the marker concentration curves indicated a rapid rate of food transit through the gastrointestinal tract, as has be en observed in several (but not all) pinniped species.