360 
PACIFIC SCIENCE, VoL XXII, July 1968 
TABLE 2 
Food Items in Stomach of Rabbit 2759 with 
Poor Dental Occlusion, from Manana 
Island, Hawaii 
PLANT 
PARTS EATEN 
% BY 
VOLUME 
Atriplex 
Leaves and stems 
18 
semibaccata 
Seeds in utricles 
27 
Nicotiana 
Whole flowers, leaf frag- 
tabacum 
ments 
30 
Seeds and parts of 
capsules 
3 
Grasses 
Leaves and stems cut in 
5-10 mm lengths 
15 
Ly coper si con 
Whole fruits, pulp, seeds, 
esculentum 
and skins 
7 
Portulaca 
oleracea 
Seeds 
trace 
Total 
100 
TABLE 3 
Food Items in Stomach and Rectal Pellets, of 
Seven Rabbits with Good Dental Occlusion, 
from Manana Island, Hawaii 
ANIMAL 
NO. 
FOODS IDENTIFIED 
2754 
Grass stems and leaves 
2755 
Grass fragments; Portulaca oleracea leaves 
2756 
Grass fragments ; P. oleracea leaves ; 
Lycopersicon esculentum leaves 
2757 
Grass fragments ; Nicotiana tabacum seeds ; 
Atriplex semibaccata fruits 
2758 
Grass fragments; L. esculentum leaves 
2760 
Grass fragments ; N. tabacum seeds ; P. 
oleracea seeds 
2761 
Grass fragments; P. oleracea leaves 
made. This is in contrast with rabbit 2759, in 
which grasses comprised only 15% of the 
stomach contents on a volumetric basis. There 
seem to be at least two explanations for these 
differences. Animal 2759 may have had differ- 
ent food preferences because of the poor con- 
dition of his teeth, or may have eaten less grass 
than the other animals because of his possibly 
restricted range on the outer slope of the island. 
He appeared undernourished but not thin; pre- 
pared skeletal parts were fat-free compared to 
those of six other rabbits, and in flexing the 
thawing body for skinning, two legs were 
broken under little pressure. This was the oldest 1 
rabbit examined and probably an outcast who 
never ventured onto the main crater floor. 
Mykytowycz (1964) reports well-defined terri- 
toriality in the wild rabbit as well as a social 
heirarchy among males. On the other hand, 
grasses have many thick-walled lignified cells 
which are not digested readily, and are more 
likely to pass through the intestinal tract than 
such thin-walled unlignified materials as to- 
mato fruits and tobacco flowers. Rabbit 2759 
was able to digest little of its poorly chewed | 
food, for the rectal pellets contained seeds of 
salt bush, tomato, tobacco, and purslane, as 
well as large pieces of grass stems, tobacco 
capsules, and tomato skins — virtually all the 
items eaten, except for tomato fruit pulp and 
tobacco flowers. Rabbits with good occlusion 
have reasonably complete digestion of many 
food materials other than grass fragments, so 
that recovered materials are often mostly grass 
fiber. Perhaps a combination of differences in 
local availability of foods and inefficiency of 
their use account for the differences in food 
residues between rabbit 2759 and the others. 
Animal 2757, a female, was the only other rab- 
bit in which salt bush was identified. She was 
the other member of the 33- to 38-months age 
class. 
Most fragments of grass could not be identi- 
fied as to genus, but those which could be 
identified proved to be either Cenchrus or 
Trichachne. These were the two most com- 
mon species on Manana at the time of the study, 
and unless there is great preferential feeding 
by the rabbits, one would expect them to occur 
most commonly in the food materials sampled. 
Munro (1950) reported that rabbits on 
Manana were eating roots of Boerhavia tet- 
randa (== diffusa). This plant has a large 
fleshy taproot which is a good source of food, 
but no identifiable fragments of it were re- 
covered from the rabbits we studied. However, 
such material probably would be digested 
readily and would be difficult to detect. Rab- 
bits had gnawed the bark from some erect 
woody stems of Nicotiana tabacum and had also 
scratched the soil from some of the plants, bar- 
ing the roots which were then gnawed (Fig. 6). 
Aside from Atrip lex semibaccata , which grew 
only on the lower, outer slopes of the main 
