Post by Ceratodromeus on Jan 30, 2020 5:15:52 GMT 5
Predatory behavior of yellow baboons
Introduction
This paper describes the predatory behavior of yellow baboons (Papio
cynocephalus) in the Masai-Amboseli National Park, Kenya. During a
14 month period, the members of one baboon group caught and ate 45
vertebrate prey. This report describes these predation episodes and provides
information on vertebrate prey species utilized, methods of capture and
consumption of prey, seasonal variation in predation rates, and distribution
of prey among group members. Additionally, the probable effect of baboon
predation on prey populations will be evaluated and the possible nutritional
importance of vertebrate prey to baboons briefly considered.
African hare
African hares were frequently flushed from cover by foraging baboons
and were then vigorously pursued by one or more individuals. Group
members of almost all age classes and both sexes participated in the chase
of hares; however when a hare was captured by an adult female or a juvenile, they usually succeeded in eating only a few bites before an adult
male supplanted them from the prey. Baboons not actually participating in
the chase often produced a loud chorus of so-called cohesion or arousal
grunts. When a hare eluded the baboons by running into a bush or beneath
a log, the baboons tore at the hiding place but usually failed to flush the
hare a second time.
Hares were consumed until no more than a few small scraps of fur and
bone remained, and sometimes even these were eaten by juveniles. The
first parts of the hare eaten were the flesh from the head or the gluteal
muscles; skull bones, brains, long bones, and vertebrae were consumed
last. Baboons captured a prey item in 78.9% of their chases of African
hares (N= i9), and the lower bound for the median duration of these
episodes was I9 minutes. The hourly rates of predation on hare showed a
bimodal distribution; the first peak occurred around 1100 hours and a second
but lesser peak occurred between 1500and 1700 hours. This bimodal diurnal
distribution of predation on hares corresponds closely to the diurnal distribution of foraging activity by Amboseli baboons (ALTMANN & ALTMANN,
I970).
Vervet monkeys
Adult male baboons definitely hunted or stalked young vervet monkeys
in the strict sense of these words. In fact, adult males were the only group
members observed to stalk or capture vervets, and adult males also consumed most of the resulting carcasses. Juvenile vervets in the 6 month to
2 year old age range often formed play-groups in isolation from adults, and
it was these juveniles that were caught by baboons. In a typical hunting
sequence, a single adult male baboon left a group progression and moved
casually toward a subgroup of playing vervets. After moving 10 to 15
meters toward the vervets, the male halted, fed- briefly and then again
moved closer to the vervets. Eventually, the male either leaped into a tree
that contained vervets or chased one from the ground into a tree.
Juvenile vervets trapped in a tree by a baboon either crouched in "fear
paralysis" in the terminal branches of the tree or dropped to the ground
and ran for cover. If in leaving the tree the vervet tried to leap past the
baboon or to outrun it once on the ground, the results were fatal. In contrast, vervets that crouched motionless in the terminal branches of a tree or
in the underbrush usually escaped capture. Throughout the chase and attempt
at capture, adult vervets gave alarm barks, but did not physically attack
the baboon or otherwise defend their young.
Vervets were killed immediately upon capture, usually by a single bite
into the chest or ventrum. The first parts consumed were flesh from the
chest and rib cage, head flesh, or gluteal muscles. The last parts consumed
were brains and skull bones, tail vertebrae, and long bones. When the
baboons abandoned the prey item, only the entrails remained and even
these had been scraped clean of any adherent fat and blood. In short, very
little of a vervet went uneaten.
Baboons successfully caught a vervet monkey in 52.6% of their chases
of this species (N=19), and the lower bound for the median duration of
these epsiodes was 37 minutes. Rates of predation on vervets were approximatelytwice as high in the intervals from 0700 to 1000 and from I700 to
1900 than in the intervening hours. This particular diurnal distribution of
predation on vervets probably reflects the close spatial proximity of vervet
and baboon groups in the early morning and late afternoon hours when
their day-ranges overlapped at sleeping groves.
Neonate gazelle
Neonate gazelle, those still cached in tall grass by their mothers, were also
killed and eaten by baboons. Most episodes of predation on gazelle began
when a baboon found the neonate apparently by accident. However, on
several occassions, adult males left a group progression and walked backand-forth through a stand of Sporobolus consimilus, the grass in which
neonate gazelle in Amboseli are most often hidden. Similar prey-searching
behavior by baboons has been reported by BARTLETT & BARTLETT (196I)
and by HARDING (0973a).
The gazelle was seized by one or more adult males and carried into the
open shortly after it was located. The loud, bleating distress call of the
gazelle alerted its mother, and although she was able to chase individual
adult males away from her offspring by butting and kicking, other males
continued to bite at the neonate. The gazelle died within 10 to 15 minutes
after the baboons began eating it, and once the distress call ceased, its
mother terminated her defense.
Baboons first ate the intestines and viscera of neonate gazelle, in contrast to their consumption of vervet monkeys; the gluteal muscles and muscles of the upper hindlimb were consumed secondly. The last parts of the
carcass consumed were the femura which were cracked into pieces, chewed
and swallowed. Baboons in Alto's Group were never observed to crack
open a gazelle skull or otherwise extract the brains as was common among
Gilgil baboons (HARDING, 1973a); however an adult female in another
Amboseli group was observed to do so (S. MCCUSKEY, pers. comm.) Thus,
when Alto's Group abandoned a gazelle, the head was intact, usually
joined by large straps of skin to the bones of the lower legs and hooves.
The lower bound of the median duration of episodes of predation on gazelle
was 29 minutes, although one episode lasted over three hours. The hourly
rates of predation on gazelle peaked between 1200 and 1500 hours, times
of day when baboons were frequently in open grassland where young
gazelle are cached.
amboselibaboons.nd.edu/assets/83933/19.pdf
Introduction
This paper describes the predatory behavior of yellow baboons (Papio
cynocephalus) in the Masai-Amboseli National Park, Kenya. During a
14 month period, the members of one baboon group caught and ate 45
vertebrate prey. This report describes these predation episodes and provides
information on vertebrate prey species utilized, methods of capture and
consumption of prey, seasonal variation in predation rates, and distribution
of prey among group members. Additionally, the probable effect of baboon
predation on prey populations will be evaluated and the possible nutritional
importance of vertebrate prey to baboons briefly considered.
African hare
African hares were frequently flushed from cover by foraging baboons
and were then vigorously pursued by one or more individuals. Group
members of almost all age classes and both sexes participated in the chase
of hares; however when a hare was captured by an adult female or a juvenile, they usually succeeded in eating only a few bites before an adult
male supplanted them from the prey. Baboons not actually participating in
the chase often produced a loud chorus of so-called cohesion or arousal
grunts. When a hare eluded the baboons by running into a bush or beneath
a log, the baboons tore at the hiding place but usually failed to flush the
hare a second time.
Hares were consumed until no more than a few small scraps of fur and
bone remained, and sometimes even these were eaten by juveniles. The
first parts of the hare eaten were the flesh from the head or the gluteal
muscles; skull bones, brains, long bones, and vertebrae were consumed
last. Baboons captured a prey item in 78.9% of their chases of African
hares (N= i9), and the lower bound for the median duration of these
episodes was I9 minutes. The hourly rates of predation on hare showed a
bimodal distribution; the first peak occurred around 1100 hours and a second
but lesser peak occurred between 1500and 1700 hours. This bimodal diurnal
distribution of predation on hares corresponds closely to the diurnal distribution of foraging activity by Amboseli baboons (ALTMANN & ALTMANN,
I970).
Vervet monkeys
Adult male baboons definitely hunted or stalked young vervet monkeys
in the strict sense of these words. In fact, adult males were the only group
members observed to stalk or capture vervets, and adult males also consumed most of the resulting carcasses. Juvenile vervets in the 6 month to
2 year old age range often formed play-groups in isolation from adults, and
it was these juveniles that were caught by baboons. In a typical hunting
sequence, a single adult male baboon left a group progression and moved
casually toward a subgroup of playing vervets. After moving 10 to 15
meters toward the vervets, the male halted, fed- briefly and then again
moved closer to the vervets. Eventually, the male either leaped into a tree
that contained vervets or chased one from the ground into a tree.
Juvenile vervets trapped in a tree by a baboon either crouched in "fear
paralysis" in the terminal branches of the tree or dropped to the ground
and ran for cover. If in leaving the tree the vervet tried to leap past the
baboon or to outrun it once on the ground, the results were fatal. In contrast, vervets that crouched motionless in the terminal branches of a tree or
in the underbrush usually escaped capture. Throughout the chase and attempt
at capture, adult vervets gave alarm barks, but did not physically attack
the baboon or otherwise defend their young.
Vervets were killed immediately upon capture, usually by a single bite
into the chest or ventrum. The first parts consumed were flesh from the
chest and rib cage, head flesh, or gluteal muscles. The last parts consumed
were brains and skull bones, tail vertebrae, and long bones. When the
baboons abandoned the prey item, only the entrails remained and even
these had been scraped clean of any adherent fat and blood. In short, very
little of a vervet went uneaten.
Baboons successfully caught a vervet monkey in 52.6% of their chases
of this species (N=19), and the lower bound for the median duration of
these epsiodes was 37 minutes. Rates of predation on vervets were approximatelytwice as high in the intervals from 0700 to 1000 and from I700 to
1900 than in the intervening hours. This particular diurnal distribution of
predation on vervets probably reflects the close spatial proximity of vervet
and baboon groups in the early morning and late afternoon hours when
their day-ranges overlapped at sleeping groves.
Neonate gazelle
Neonate gazelle, those still cached in tall grass by their mothers, were also
killed and eaten by baboons. Most episodes of predation on gazelle began
when a baboon found the neonate apparently by accident. However, on
several occassions, adult males left a group progression and walked backand-forth through a stand of Sporobolus consimilus, the grass in which
neonate gazelle in Amboseli are most often hidden. Similar prey-searching
behavior by baboons has been reported by BARTLETT & BARTLETT (196I)
and by HARDING (0973a).
The gazelle was seized by one or more adult males and carried into the
open shortly after it was located. The loud, bleating distress call of the
gazelle alerted its mother, and although she was able to chase individual
adult males away from her offspring by butting and kicking, other males
continued to bite at the neonate. The gazelle died within 10 to 15 minutes
after the baboons began eating it, and once the distress call ceased, its
mother terminated her defense.
Baboons first ate the intestines and viscera of neonate gazelle, in contrast to their consumption of vervet monkeys; the gluteal muscles and muscles of the upper hindlimb were consumed secondly. The last parts of the
carcass consumed were the femura which were cracked into pieces, chewed
and swallowed. Baboons in Alto's Group were never observed to crack
open a gazelle skull or otherwise extract the brains as was common among
Gilgil baboons (HARDING, 1973a); however an adult female in another
Amboseli group was observed to do so (S. MCCUSKEY, pers. comm.) Thus,
when Alto's Group abandoned a gazelle, the head was intact, usually
joined by large straps of skin to the bones of the lower legs and hooves.
The lower bound of the median duration of episodes of predation on gazelle
was 29 minutes, although one episode lasted over three hours. The hourly
rates of predation on gazelle peaked between 1200 and 1500 hours, times
of day when baboons were frequently in open grassland where young
gazelle are cached.
amboselibaboons.nd.edu/assets/83933/19.pdf
