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TitleAnimal Behavior Animal Life in Groups
File Size8.3 MB
Total Pages125
Table of Contents
                            Contents
1: Living Together
2: Groups for Survival
3: Colonies of Ultimate Cooperators
4: Schools and Flocks
5: Herds
6: Predator Groups
7: Primate Societies
8: Ecology and Groups
Glossary
Bibliography
Further Resources
Picture Credits
Index
About the Author
                        
Document Text Contents
Page 2

Christina Wilsdon

animal

life in Groups

Page 62

61

Herds

every yeAr on Africa�s Serengeti Plains, hundreds of thou-
sands of wildebeest migrate. They leave dry plains and wood-
lands behind and follow the seasonal rains southward for several
hundred miles, looking for fresh grass to eat. They may not be
bonded to each other and they have no leader, but every wilde-
beest is dependent on the group.

Wildebeest herds are great examples of sel�sh herds. Each
animal tries to stay safe in the center of the herd, where no preda-
tor can reach. The herd seems leaderless, disorganized, and even
chaotic, but it drives forward as one, seeking the food it needs to
survive.

offering up A feASt
February, when the plains are lush with green grass, is the time
of greatest danger for a wildebeest herd. Thousands of female
wildebeest give birth to calves in synchrony with one another.
The birthing period lasts for about three weeks. Females lie
down, give birth in about 10 minutes, and are on their feet as
soon as possible. The calves are up and running within minutes
of being born. Quick births and strong-legged newborns are

5

Page 63

62 AnimAl life in groupS

essential to wildebeest survival because predators have been fol-
lowing the herd. Lions, leopards, hyenas, cheetahs, and jackals
wait for birthing season. Every female on the ground is vulnera-
ble to a predator. Thousands of newborn calves are taken as prey,
even before they can get to their feet. On the open plains of the
Serengeti, there are no hiding places. Only the calves and moth-
ers that can run with the herd will survive the predator attacks.
By taking wildebeest females and calves as prey, the predators
help ensure their own survival and the survival of their young.

Migrating wildebeest travel in a herd, like this one crossing the Mara
River in Africa. Individuals may be initially hesitant to plunge into the
river, but the urge to push onward, follow the herd, and � nd fresh grass
to eat takes over.

Page 124

index 123

survival
and food, 61
genes, 39, 54, 60, 63,

75, 94, 101
and predators, 62–63,

66, 71, 101
strategies, 47, 49, 52,

56, 78–79, 91–92,
94, 96

and thriving groups,
7, 9, 11–12, 17–18,
21, 23–26, 28,
31–32, 44–45, 87

swans, 57

T
termites, 35
To Touch a Wild Dolphin

(Smolker), 72, 74
trematode, 103–104

U
University of Rhode

Island’s Sea Grant
Program, 46

V
vampire bats, 32
Vedder, Amy, 100

W
wasps, 35
Weaver, Sigourney, 21
Weber, Bill, 22, 100
wild dogs, 63
wildebeest

birthing periods,
61–63

migration, 61, 64,
100

research, 63
survival, 61–63, 70,

101
winter fl ocks, 56
wolves

alpha, 80–81
communication, 82
and hunting, 81
omega, 81
research, 81
social life, 79–83
structure, 80–81

worms, 38

Z
zebras

migration, 70
selfi sh herd, 70

zoology, 24

Page 125

124

About the Author

toney Allman currently lives in Virginia and has written more
than 30 non� ction books for students. She holds a bachelor of sci-
ence from Ohio State University and a master of arts in psychol-
ogy from University of Hawaii. Allman has a longstanding inter-
est in the sciences in general and in the determinants of behavior
in particular. She believes animal behavior is both fascinating
and an important area of study if people are to truly understand
themselves. One of her � rst assignments as a new graduate stu-
dent was to observe the gorilla�s behavior in the Honolulu Zoo.

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