General Features of Diet.š Influence on Prey Populations. Competitors and Scavengers.
An adult tiger "over a short period of time...is capable of consuming
a large amount of meat.š For example, once a large male, without changing
his position (lying on his stomach), ate a roe deer that he had knocked down
without leaving any part of it uneaten...Another male ate 75% of the carcass
of a "seven-point" Manchurian deer (not less than 80 kg of meat and bones)
over a period of less than 3 days " (Fig. 40) (Yudakov
1973, p. 93).š An estimate of the normal amount of food required by tigers
is made more difficult by the fact that a prey animal is caught by the tiger
within a time period that is neither preset nor equal to a regular time unit.š
It is already possible to make a judgment about this simply by considering
the fluctuations in the success rate of the tigers' hunts, which have been
examined in the previous chapter.š For the tiger "it is natural to go hungry
for up to 10 or more days.š The time between successive prey kills ranges
from several hours up to 11 days, averaging 5 days" (Yudakov 1974, p. 355).
In order to present approximate quantitative indices characterizing the
tiger's diet, it is advisable first to utilize data from those tracking episodes
where the segment of the series of footprints had a sufficiently clear temporal
referencing.š By summing together such segments for male tigers, we will
produce a characterization of their lives over a 41-day period (460 km of
tracking).š Over that interval of time, there were ten prey kills with one
animal being an adult female wild boar that had been killed by a tigress but
that was eaten by her together with a male tiger during their joint travels.š
There were eight wild boar (7 of which were yearlings) and two Manchurian
deer (an adult bull and an adult female) among the ten prey kills.š With the
exception of one of the Manchurian deer, more than 75% of the weight of each
animal was consumed.š The total quantity of meat and bones consumed was approximately
300 kg.š If we extrapolate this result to an entire year, we arrive at a
value of 2,600-2,700 kg.š This means that, on average, a male tiger eats
only somewhat more than 50 kg of meat per week.
A calculation based on the total aggregate of the data is still more
approximate in nature.š It is based on the use of an index of the average
daily travel distance, with the aid of which it is possible to roughly estimate
the total number of 24-hour periods in the life of tigers that have been characterized
by our tracking.š Such a computation for male tigers gave results that are
extremely close to those that we have just examined.
There were 11 prey kills for 28 24-hour periods in the life of tigresses
(219 km of tracking).š The species composition of their prey is more diverse
than in the previous case: six wild boar (two adults, four piglets); one yearling
Manchurian deer (saek); one musk deer, and one dog. Such, we may assume,
is the monthly ration for one individual female.š It amounts to approximately
250 kg of meat.š This index exceeds that for males, however, a calculation
based on the total aggregate of data leads to the opposite conclusion: the
female's demand for food is significantly less than that of males.š In any
event, estimates that were arrived at using a variety of methods are similar
and, apparently, reflect the true orders of magnitude.š If over the course
of a week, a tiger requires more than 60 kg of meat, then for an entire year
this comes to slightly less than 3,000 kg.
Figure 40.š The remains of a Manchurian deer killed by the male "Emperor"
tiger.
Our estimates are very close to analogous indices calculated by L. G. Kaplanov
(1948).š According to the data of this investigator, an individual tiger consumes
approximately 3,000 kg of meat over the course of a year, which corresponds
to 30 nominal prey animals each weighing 100 kg.š Since young animals predominate
among the tigers' prey, the actual number of prey turns out to be considerably
greater than these 30 nominal animals: in our case, it is 90 individuals
for males, while for females, it is greater than 120 individuals.š Here an
estimate made using the total aggregate of the data also partially equalizes
the difference between males and females, with the number of individuals
captured per year becoming less and approximating the estimate that has been
published earlier by A. G. Yudakov (1973): 70-75 animals.š The difference
between males and females reflects not so much the total amount of food eaten
by them, so much as the dimensions of the animals that comprise the prey.š
"An adult female kills a greater number of animals, but smaller animals predominate
among her prey" (Yudakov 1973, p. 93).
During the course of all the years of our study, the main prey of tigers
in the study region was wild boar (Table 18).š Not less
than half of the prey, on average about 60%, was attributed to this species
in each of the seasons.š Manchurian deer constituted only a quarter of all
the animals killed by tigers.š Other species occupied a secondary position
in the tiger's diet.š In comparing the data on the population sizes of ungulates
in the long-term study site (cf., Table
4) with the relative importance of different prey species in the diet
of the tiger, it is clear that these predators kill wild boar more often than
would be expected based on the ratios of the densities of prey populations.š
Thus, in the winter of 1970-1971, Manchurian deer were even more numerous
than wild boar in the study region, but half of the animals captured by tigers
were attributed to the latter species, while Manchurian deer made up less
than a quarter of all prey killed.š These differences find an explanation
in the difference in the success rates of these predators' hunts on Manchurian
deer and wild boar, a fact that has already been mentioned.
Prey composition of tigers in the long-term study area (based on finds
of prey remains supplemented data derived from an examination of the tigers'
excrement).
š
| Winter Season |
Total Number of Prey |
Wild Boar |
š | Manchurian Deer š |
š | Roe Deer |
š | Musk Deer |
š | Himalayan Bear |
š | Dog |
š |
| Total |
% | Total |
% | Total |
% | Total |
% | Total |
% | Total |
% | ||
| 1970/71 | 14 | 7(2) | 50 | 3 | 21.4 | - | - | 1 | 7.1 | 2 | 14.3 | 1 | 7.1 |
| 1971/72 | 22 | 13(4) | 59.1 | 5(1) | 22.7 | 3 | 13.6 | - | - | - | - | 1 | 4.6 |
| 1972/73 | 28 | 18(2) | 64.3 | 8 | 28.5 | 1 | 3.6 | 1 | 3.6 | - | - | - | - |
| Total | 64(9) | 38(8) | 59.4 | 16(1) | 25.0 | 4 | 6.3 | 2 | 3.1 | 2 | 3.1 | 2 | 3.1 |
Note:š The number of data points included in the total data set
based on the analysis of tigers' excrement is given in parentheses.š The latter
source of data was taken into account only in those instances were these
data gave information on prey that we did not discover during our tracking.
Selectivity is also manifested in the ratio of the age composition, and
also partly of the sex ratio of the prey.š The percentage of yearlings among
the wild boar killed by tigers is considerably higher than its percentage
in the population (Table 19).š The same could also be
justifiably said of the "sayok" (or yearling) Manchurian deer (Table 20).š The proportion of adult bulls of the Manchurian
deer that are part of the prey composition of tigers is relatively low.š Apparently,
this sex and age group suffers the least from the tiger.š The effect of the
predator is directed in the present instance, as can be seen from these data,
above all toward the utilization of the annual population increase.š With
the transition of young ungulates to older age groups, their risk of death
from the tiger decreases substantially.
On the basis of the available data we can only make approximate calculations
with respect to a general estimation of the annual losses to the wild boar
and Manchurian deer populations from the tiger.š A sufficiently reliable estimate
can be presented only for the snow season (five months--from the middle of
November to the middle of April).š The proportion of individuals removed
from the populations of ungulates by the tiger is calculated for an area
of approximately 900 km2, where we carried out continuous observations.š
A male tiger and a female, which had two cubs during the first half of this
time period and one cub in the second half, lived here over the course of
three winter seasons.š In the final season of our observations another male
transited through this territory, and, toward spring, we noted the footprints
of yet another female, which had two cubs.š Provisionally, it is possible
to accept an estimate of three adult individuals as inhabiting the area in
question.
Age composition of the wild boar population (based on encounters with
these animals) and the percentages of animals of different ages that became
the prey of tigers.
š
| Composition
of the Sample |
Number of Individuals
Counted |
Adults |
Yearlings |
||
| Total |
% | Total |
% | ||
| Live Wild Boar Observed |
144 | 53 | 36.8 | 91 | 63.2 |
| Prey of the Tiger |
30 | 7 | 23.3 | 23 | 76.7 |
Age composition of the Manchurian deer population (based on encounters
with these animals) and the percentages of animals of different ages that
became the prey of tigers.
š
š
| Composition of the Sample | Number of Individuals Counted | Adult Males |
Adult Females |
Yearlings | |||
| Total | % | Total | % | Total | % | ||
| Live Manchurian Deer Observed |
93 | 22 | 23.7 | 28 | 30.1 | 43 | 46.2 |
| Prey of the Tiger |
15 | 2 | 13.3 | 4 | 26.7 | 9 | 60.0 |
The number of 24-hour periods in the life of the tigers that we tracked
is determined by the total tracking length and the average 24-hour run.š Estimates
made using single segments of the tigers' journeys are, in our opinion, less
informative here due to the relatively small amount of data available in
the present case, and also due to fluctuations in the success of the hunts
in winters with varying snow conditions.š Summing up for 148 "estimated"
24- hour periods in the lives of all the animals that we had under observation,
they had killed 19 wild boar and 7 Manchurian deer.š These data may conditionally
be ascribed to a single tiger's life.š Taking into consideration the differences
in prey composition and in the quantity of prey taken by male and female
tigers, it is possible to conclude that the three tigers captured up to 60
wild boar and 20 Manchurian deer over the course of five winter months.
The mean indices of the population densities of wild boar and Manchurian
deer in the long-term study site over the course of three winter seasons were
4.2-5.0 and 3.5-4.0 individuals per 10 km2, respectively.š Comparing
these figures with the results produced above, it is possible to conclude
that over the course of a single snow season, the tigers in the sector under
our observation removed on average up to 14% of the wild boar population
and up to 6% of the Manchurian deer population.š The annual losses to the
populations of prey are approximately twice as large.š With regard to wild
boar, the magnitudes of these estimates that we have calculated are very
close to the estimates which A. G. Yudakov (1973) made on the basis of preliminary
computations from our data, but the percentage removed from the Manchurian
deer population is significantly less that the proportion originally accepted
(i.e., in Yudakov's earlier estimates).
Domestic animals in that part of Sikhote-Alin where we conducted our
observations are an insignificant element in the diet of tigers.š According
to the information that we succeeded in gathering, the number of cases of
attacks on livestock and dogs over the course of more than half a century
amounts to several 10s of events (23 instances were recorded, Table 21).š Moreover, during the years of our work, only
dogs perished due to tigers.š Almost all these cases took place in the taiga
when dogs were used during hunting.
Only the brown bear can play the role of a competitor with the tiger
in our study region, and then mainly only during a very brief period of the
year--early spring.š After their emergence from their dens, which are concentrated
near the divides of watersheds, the bears descend into the lower zones of
the mountains, where they begin hunting wild boar and Manchurian deer.š We
had already noted their first appearance in the middle of March in areas where
the tigers constantly traveled.š It was precisely here that we observed (by
tracking) a hunt by a brown bear on Manchurian deer at the end of this month.š
We twice found the remains of ungulates that had been killed by brown bears
during the spring season: in March, the remains of a musk deer and in April,
the remains of an adult Manchurian deer.š In April, we observed a case where
a Himalayan bear (we observed him visually) was feeding on the remains of
a Manchurian deer that had been killed by a tiger.š In autumn, the footprints
of bears were common up until the beginning of December.š Our latest (for
the season) encounter with the footprints of a brown bear took place on December
21.š In the pre-winter period, only one animal that had fallen prey to a
brown bear was discovered: this was a wild boar killed at the end of November.
Incidents of tiger predation on domesticated animals in the basin
of the Malinovka River (up to 1973).
š š
| Date |
Type of Animal Killed |
Number of Individuals |
Location and Circumstances of the Attack |
Author of the Report |
| 1912
š š |
Horse |
1
š š |
Village of Savinovka (in a stable),
owner: N. Romanyuk |
A.M. Urbanovskii š š |
| 1920
š š |
Bull š š |
1
š š |
Near the settlement of Mezhdurech'e,
owner: Vigovskii |
V.A. Yarich š š |
| 1938 | Dog |
1 | Near the settlement of Martynova
Polyana, owner: Vorozhbit, the tiger killed the dog in his presence |
N.M. Vorozhbit |
| 1951, summer | Horse |
3 | Near the settlement of Polyana,
in a pasture, one of them was a foal |
N.A. Pervukhin |
| 1951, November | Dog | 1 | Near the settlement of Polyana,
killed by a tiger in the presence of a hunter |
N.A. Pervukhin |
| 1952, February | Cattle |
3 | Settlement of Polyana, in a stockyard |
N.A. Pervukhin |
| 1958 | Dog | 3 | Upper reaches of the Malinovka
River, during a hunt, owner: Drachuk |
P.E. Asyrkin |
| 1958 | Cow |
1 | At a distance of 4 km from the
settlement of Ariadnoe, in a pasture |
A.M. Ivashchenko |
| 1958 | Horse |
1 | Near the settlement of Pozhiga |
K.G. Abramov, 1965 |
| Unknown |
Dog | 2 | Pyatyi Stream (Bystraya River),
owner: A. Prokopchuk |
D.M. Dobroshevskii |
| Beginning of the 1960s, summer |
Cow |
1 | Near the settlement of Pozhiga,
owner: K.I. Darenskii |
P.E. Asyrkin |
| 1967 | Dog | 1 | Bogdanov Stream (Gornaya River),
killed in the presence of hunters by a tiger |
A.V. Deryagin |
| 1968, autumn |
Dog | 2 | Orekhovka River, on a hunt |
N.A. Pervukhin |
| 1969, May | Horse |
1 | Village of Lyubitovka |
A.F. Novitskii |
| 1970, autumn |
Dog | 2 | Lazarev Stream (Titovka River),
at an apiary, owner: Shchegolyuk |
G.F. Gorokhov |
| 1970, September | Cow |
1 | Settlement of Pozhiga, in a pasture,
owner: P.A.Toporkin |
P.E. Asyrkin |
Table 21 (cont.)
š
| Date | Type of Animal Killed | Number of Individuals | Location and Circumstances of the Attack | Author of the Report |
| 1970, November |
Dog | 1 | Upper reaches of the Malinovka
River, on a hunt, owner: Artemenko |
G.F.Gorokhov |
| 1970, December | Dog | 1 | Settlement of Martynova Polyana,
owner:Volokotyuk |
A.V. Deryagin |
| March 9, 1971 | Dog | 1 | Pravyi Igristyi Stream (Gornaya
River), found in the taiga without its owner |
Tracking Data |
| November 15, 1971 | Dog | 1 | Kammenyi Stream (Gornaya River),
on a hunt, owner: A. Kiryushkin |
Tracking Data |
| 1971 | Dog | 1 | Upper reaches of the Malinovka
River, on a hunt, owner: G. I. Korzh |
P.E. Asyrkin |
| 1972, January | Dog | 2 | Klinovka Stream (Orekhovka River),
on a hunt, owner: Grigor'yev |
T.L. Trofanchuk |
| 1973, October | Dog | 1 | Bystryi Stream (Orekhovka River),
on a hunt |
Information collected by A.G.
Yudakov |
In one case, we observed a direct encounter between a tiger and a lynx
by monitoring their tracks.š The tigress, having encountered a lynx near
a roe deer that the lynx had killed along her route, stopped, sat down, and
then rushed to the site by leaping and drove the lynx away from her prey.
For our long-term study site, we found that the interactions between
the tiger and scavengers-commensals that were examined in greatest detail
by E. N. Matyushkin (1974) for the eastern macroslope of the Central Sikhote-Alin
Mountains were exactly the same as those described by Matyushkin.š Here,
the main beneficiaries of the remains of the tigers' prey were also the large-billed
crow (Corvus macrorhynchus) and the raven (Corvus corax).š
Among the other birds, that we observed at the prey killed by tigers were
the jay (Garrulus glandarius), the Eastern blue magpie (Cyanopica
cyana), the nuthatch (Sitta sp.), and the Siberian tit (Parus
cinctus) (Fig. 41).š Without question, the Siberian
jay (Perisoreus infaustus) also belongs among the scavengers of tigers'
kills, although we did not observe it in such a situation on even as single
occasion.š In places where this bird is common, it often falls into hunters'
traps, to which it flies, being attracted by the bait.š Among mammalian scavengers,
the Siberian weasel (Mustela sibirica) feeds more frequently than
others on the tigers' kills.š We encountered the following scavengers on
a single occasion each: a mink (Mustela lutreola)š (which was frightened
away from the remains of a roe deer), a group of yellow-throated marten (Martes
flavigula), a sable (Martes zibellina), a raccoon dog (Nyctereutes
procyonoides) and a Himalayan bear.š In four cases, wild boar ate carrion
(three times, it was the remains of a Manchurian deer and once the remains
of a roe deer).š The remains of the wild boar themselves, around which we
once found their tracks, were not touched by the wild boar.š Wild boar ate
not only carrion that was lying out in the open, but they also dug up carrion
from under a thick layer of snow (Fig. 42).
An examination of the remains of 42 of the tiger's prey allows us to
conclude that the plunderers of the tiger's prey misappropriated approximately
15% of that part of the prey that the main scavengers are capable of utilizing.
Figure 41.š A jay (Garrulus glandarius) feeding on the remains
of a tiger's prey: a yearling wild boar.
Figure 42.š The remains of a roe deer killed by a tiger after having
been dug out from under the snow by wild boar.
š
š