WARTHOG, Phacochoerus aethiopicus
WHAT IT IS
Naked swine of the savanna. Slimmer than other hogs, with level back and
comparatively long limbs. Male wt 150-220 lb (68-100 kg), ht 27 in (68 cm);
Female 99-156 lb (45-71 kg), ht 24 in (60 cm). Head: large with flat face;
prominent tusks, uppers average c. 8 in (20 cm) for male, up to 24 in (60 cm),
lowers 4 in (10 cm); much shorter in female; prominent "warts" (thickened skin
and gristle) below eyes, up to 6 in (I 3 cm) long in mates, mere bumps in
females and young. Coat: scattered bristles, whiskers, and a mane of long
hair. Color: skin gray; mane and tail tuft dark; cheek whiskers white,
shaped like tusks. Harderian glands in eye sockets leave dark stains on
male's face. Teats: 4.
WHERE IT LIVES
Northern and Southern Savanna and adjacent arid zone, absent only from
deserts, rainforest, and mountains above 10,000 feet (3000 m).
GOOD PLACES TO SEE IT
Common in virtually every park with savanna habitat, but opportunities to
see approachable hogs on short pasture are limited. A few of the better
spots: Nairobi and Amboseli NP, Masai Mara NR, Kenya; Arusha, Manyara,
and Serengeti NP, Tanzania; Chobe NP, Botswana; Kruger NP, South Africa.
A true savanna dweller that avoids dense cover and forest but depends on
burrows to escape predators and temperature extremes, especially in infancy.
Although warthogs dig quite well, using snout as shovel, most holes they
use have been excavated by aardvarks. Whether warthogs live in areas
uninhabited by aardvarks is an open question.
Unequalled ability to exploit buried and highly nutritious rhizomes, bulbs,
and such enables as many as 78 warthogs/mi2 (30/kM2) to thrive in the best
habitat, namely fertile alluvial soils with a good cover of palatable
grasses or species with edible rhizomes. With molar teeth and jaw hinge
modified for grinding grass, warthogs graze when grass is green and use
their hard-edged snout disk to uncover rhizomes of grasses and sedges,
tubers, and bulbs in dry season; also eat some fallen fruits. They drink
and in hot, dry weather use wallows daily.
Strictly diurnal. After traveling an average 4.3 mi (7 km) in daylight,
females and young retire before dark into I of up to 10 secure sleeping
burrows dotted within their home range, emerging the next morning-late in
cold or rainy weather. Burrows are used by different sounders on a
first-come, first-served basis. Boars are somewhat less diurnal, often
remain active for an hour or so after dark, later on moonlit nights.
They stay up late during rut to sniff out burrows occupied by sows in heat,
returning to waylay them as they emerge next morning.
Sows live in clans of related individuals that share the same resources.
Mothers and daughters with offspring up to 2 years old may stay in the
same group or in different groups that share a traditional home range
(average 430 acres, range 158-924 acres 172-420 ha]). Sounders
typically number 5 or less and include only I sow with her young of the
year, but many contain 2 mothers with their combined broods; sounders
with 4 to 5 sows occasionally number up to 16 warthogs. Associated
mothers suckle one another's young-usually a reliable sign of kinship.
Males also remain in their natal home range. After parting from females
they associate with their brothers or unrelated males until mature at 4
years. Adults only join female groups when a sow is in heat.
HOW IT MOVES
Top speed of 34 mph (55 kph) in emergencies, but warthogs in
a hurry prefer to trot@haracteristically with tail straight up like an antenna.
They lie down and get up like ruminants, not swine, kneeling on forelegs in
lying and raising the hindquarters first in rising. Feeding warthogs routinely
graze and root while resting on their callused knees.
A seasonal breeder wherever dry seasons are prolonged, mating as rains
end (3-day estrus) and farrowing 160 to 170 days later as rainy season
begins (Sept.-Dec.) in eastern and southern Africa. In higherrainfall
equatorial regions, breeding is not limited to particular months. Both
sexes fertile at 18 to 19 months, but few males breed before turning 4.
OFFSPRING AND MATERNAL CARE
Sows isolate to farrow, then stay underground nurturing 2 to 5 (rarely 6-8)
tiny, hairless piglets for the first week. Except for brief excursions or
to change dens, piglets remain in burrow 6 to 7 weeks, after which they
accompany their mother everywhere, filing behind her in a fixed order.
Begin grazing within 2 to 3 weeks but continue nursing briefly every 40
minutes or so from 3 to 6 weeks; weaned by 6 months.
Being slower with less endurance than most savanna ungulates, burrows are
essential sanctuaries when chased by cheetah, wild dog, or spotted hyena,
However, cheetahs think twice before tackling adult warthogs, are often
chased by mothers defending offspring. Fleeing juveniles pile headlong
into a hole; adults reverse direction at last instant, can then use their
tusks on pursuers that try to follow. Up to V2 offspring succumb to predators
and other causes the first year.
Although burrows keep warthogs safe at night, emerging in the morning can
be risky since lions are clever enough to sniff out occupied burrows and
patient enough to wait in ambush at breakfast time.
DIFFERENCES IN WARTHOG BEHAVIOR
Expect to see and hear Usual context and meaning
Fighting.Ritualized pushing and boxing with blunt upper
tusks and snout (no slashing or stabbing with lower tusks). Warts absorb
blows, protect eyes.
Grunting, growling, warning woomph.
Head low and mane lowered, ears flattened, backing away, squealing and
squealing growl; bolting.
Lying in contact. Especially in burrows and outside
when it is cold.
Rubbing preorbital and tusk glands together or on partner's
face and body. Often follows greeting.
Social grooming with snout and incisors: groomee solicits by lying prone
or on side with legs raised. @ Directed particularly to neck and mane.
SIGNS OF ESTRUS
Frequent urination, discoloring rear.
Adopting mating stance.
Following in a springy, hip-rolling gait, tail out and bent down, meanwhile
clacking. Clacking is a chugging noise produced by
clicking tongue or tusks, producing copious saliva.
Nuzzling, massaging, and scent-marking male's head, sides and rear; resting
chin on male's rump.
Mother and Offspring
Nose to-nose greeting, with explosive grunts.
Mother summons piglets from burrow with soft, low grunts.
Following mother in single file.
Squeaking and churring of small piglets. Expresses
"Playful" interactions of littermates mostly involve sparring and
aggressive displays. Rank order thereby established at early age.
Response to Predators
Trotting with tail vertical. Marks general arousal
rather than specific response to predator.
SOUNDS OF ALARM
Single loud alarm grunt, growl-grunt, v.,oomph (startled) call, distress
Reprinted from "The Safari Companion" by Richard Estes