Sometime ago, I posted that mountain gorillas are NOT vegans. (The claim
that mountain gorillas are vegans, is typically the "last stand" of
fruitarian zealots trying to claim that we are natural vegans/fruitarians.)
So that you have the data needed to prove that mountain gorillas are not
vegans, the following material is provided. In the material below, note:
* the deliberate consumption of ants by some mountain gorillas
* the consumption of considerable amounts of insects on the leaves that are
the basis of the diet of mountain gorillas (i.e., the mountain gorilla regularly
consumes insects, even if not deliberate).
Why do fruitarians cite the mountain gorilla to support their position?
Mountain gorillas eat mostly leaves, very little fruit, and some insects. The
mountain gorilla really does not support the position they advocate!
Also, see the interesting references on lowland gorilla diet and chimp diets,
and how chimps are more flexible in food choices. Let's see: chimps more
advanced than gorillas, chimps more flexible in food utilization than gorillas.
Humans more advanced than chimps, so humans are more flexible in food
utilization than chimps? That inference, of course, contradicts the narrow
fruitarian view.
I hope you find the material below of interest!
Regards,
Tom Billings
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Watts, D P.
Ant eating behavior of mountain gorillas.
Primates, v.30, n.1, (1989): 121-126.
Abstract:
Eleven cases of feeding on driver ants (Dorylus sp.) by mountain gorillas
(Gorilla gorilla beringei) are described. Ant eating provides the gorillas
with more animal protein and other nutrients per unit feeding time than do
other forms of insectivory that contribute to their diet, but it is so
rare that it is unlikely to be of real nutritional significance. Gorillas
obtain ants with their hands and do not use tools. Immature individuals
(except infants) ate more ants than did adult females, and silverbacks
were not seen to eat ants. These differences are more likely to reflect
differences in individual taste and interest in novelty than differences
in nutritional strategy. Not all gorillas in the Virungas population eat
ants. Intra-population variability may be ecologically contingent, but ant
eating appears to be a socially acquired and transmitted taste.
Williamson, E A; Tutin, C E G; Rogers, M E; Fernandez, M.
Composition of the diet of lowland gorillas at Lope in Gabon.
American Journal of Primatology, v.21, n.4, (1990): 265-278.
Abstract:
This report described the composition of the diet of lowland gorillas,
Gorilla gorilla gorilla, at Lope in central Gabon. This population
inhabits mature evergreen tropical forest and is not habituated to human
observers. Data were collected during 6 years of an ongoing long-term
study, from feeding-trails and by direct observation, but mostly by fecal
analysis. Gorillas ate 182 plant foods from 134 species and 36 families.
The fruit diet was diverse: 95 species were consumed, most with succulent
pulp, and some immature seeds were eaten. Fruit remains were recorded in
98% of dung. Vegetative parts of Aframomum and Marantaceae formed staple
foods, as they were abundant, accessible, and available year-round. Soil
and social insects were also ingested; remains of weaver ants were
recorded in one third of feces. More foods have been recorded for gorillas
at Lope than elsewhere and this is the most frugivorous population studied
so far.
Yamagiwa, J; Mwanza, N; Yumoto, T; Maruhashi, T.
Seasonal change in the composition of the diet of eastern lowland
gorillas.
Primates, v.35, n.1, (1994): 1-14.
Abstract:
Details are presented of the composition of the diet of eastern lowland
gorillas, derived mainly from a study of their fresh trails and fecal
analysis, during the course of an entire year in the tropical lowland
forests of the Itebero region, Zaire. Gorillas ate 194 plant foods from
121 species and 45 families. They consumed 48 species of fruits; and 89%
of fecal samples contained fruit seeds, but fruits were a relatively small
part (25%) of the total number of food items. The composition of their
diet changed seasonally. When consumption of fruit decreased in the long
rainy and the long dry seasons, the gorillas ate, in addition to
Zingiberaceae and Marantaceae, many kinds of leaf and bark, which may be
an important buffer against the shortage of fruits. Gorillas also fed
regularly on ants (Ponerinae), and the frequency of consumption showed
small seasonal variations. From a comparison of diet composition, eastern
lowland gorillas appeared to be intermediate between the other two
subspecies. The choice of food showed differences in preference of fruits
and insects between subspecies and may reflect high similarities within
subspecies in lowland and montane forests.
Tutin, C E G; Fernandez, M.
Insect-eating by sympatric lowland gorillas (Gorilla gorilla gorilla) and
chimpanzees (Pan troglodytes troglodytes) in the Lope Reserve, Gabon.
American Journal of Primatology, v.28, n.1, (1992): 29-40.
Abstract:
Sympatric populations of lowland gorillas (Gorilla gorilla gorilla) and
chimpanzees (Pan troglodytes troglodytes) in the Lope Reserve in central
Gabon consumed insects at similar average frequencies over a 7-year period
(30% versus 31% feces contained insect remains). Data came mostly from
fecal analysis supplemented by observation and trail evidence. The weaver
ant (Oecophylla longinoda) was the species eaten most frequently by both
gorillas and chimpanzees. Other species of insects were eaten but there
was virtually no overlap: Chimpanzees uses tools to eat Apis bees (and
their honey) and two large species of ants; gorillas ate three species of
small ants. Thus, despite their shared habitat, the resources utilized
were not identical as gorillas do not show the tool-use "technology" of
chimpanzees. The frequency of insect-eating by both species of ape varied
seasonally and between years but in different ways. This variation did not
seem to be related to the ration of fruit of foliage in their diets.
Gorillas of all age-classes ate insects at similar rates. Comparisons with
insectivory by other populations of gorillas indicate differences exist.
Mountain gorillas (Gorilla g. beringei) in the Virunga Volcanoes, Rwanda,
consume thousands of invertebrates daily, eating them inadvertently with
handfuls of herbaceous foods but they deliberately ingest insect-foods
only rarely. Lowland gorillas at Lope habitually ate social insects, and
their selective processing of herbaceous foods probably minimizes
inadvertent consumption of other invertebrates. Gorillas at Belinga in
northeastern Gabon, 250 km from Lope, ate social insects at similar rates
but ignored weaver ants in favor of Cubitermes sulcifrons, a small speices
of termite that occurs at Lope but was not eaten by gorillas. This
indicates that local traditions similar to those reported for chimpanzees
also exist amongst populations of gorillas.
Tutin, C E G; Fernandez, M.
Composition of the Diet of Chimpanzees and Comparison with That of
Sympatric Lowland Gorillas in the Lope Reserve Gabon.
American Journal of Primatology, v.30, n.3, (1993): 195-211.
Abstract:
Over an eight-year period, a total of 174 food items were recorded for
chimpanzees (Pan t. troglodytes) in the Lope Reserve in central Gabon.
Plant foods, principally fruit, dominated the diet but insects were eaten
regularly, and predation on at least three species of mammal occurred
infrequently. The diversity of the vegetative component of the diet
(leaves, stems, and bark) was probably underestimated by fecal analysis.
Comparison of chimpanzee diet at Lope with that of sympatric lowland
gorillas showed the majority of foods were eaten by both species (73% of
chimpanzee food items and 57% of gorilla food items). The overlap of fruit
species was greater (82% and 79%, respectively) than that of other food
classes. Both chimpanzees and gorillas harvested the majority of their
plant foods arboreally (76% and 69%, respectively). The high degree of
dietary overlap suggested that ecological competition between these two
closely related species might exist. Few overt signs of competition for
food either between or within species were observed but when fruit was
scarce, the diets of the two species showed greatest divergence. The major
differences between chimpanzee and gorilla diet at Lope were the larger
quantities of vegetative foods regularly eaten by gorillas and their
ability to resort to a diet dominated by vegetative foods when fruit was
scarce. In these respects, chimpanzees at Lope resembled populations of
Pan troglodytes studied elsewhere while Lope gorillas resembled mountain
gorillas (Gorilla g. beringei) and bonobos (Pan paniscus) in their greater
dependence on vegetative foods.
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