The particle size distribution of stomach contents from 25 tammar wallabies
(Macropus eugenii Desmarest) shot in the Okataina State
Forest and adjoining farmland near Rotorua, New Zealand, were determined.
There was a greater percentage of finer, and a smaller percentage of larger,
particles than reported in the stomach contents of larger macropods. The
chewing and biting activities of four free-ranging tammars fitted with
radio-microphone collars were monitored. Chewing rates (chews per minute) were
similar to those of other small herbivorous vertebrates. There were
significantly lower rates of chewing and higher chew-to- bite ratios when
browsing than when grazing. Observations of browsing by three captive tammars
showed inefficient handling by mutually opposed palms and digitopalmar grip,
resulting in low rates of ingestion. We suggest that tammars lower the time
necessary for fermentation of food by reducing the size of food particles, and
that their choice between graze and browse is influenced by food handling and
chewing investment.
