SUBORDER SUINA: PIGS, PECCARIES & HIPPOPOTAMI.
The Suina contains the earliest and most archaic artiodactyls.
There are 3 families alive today:
Family Suidae
(pigs)
Family Tayassuidae
(peccaries)
Family Hippopotamidae
(hippopotamuses).
The features shared by this group are:
- four-toed feet.
- little extension of distal limb bones.
- a short diastema.
- canines, upper incisors & bunodont (low
crowned) molars.
- the pre-molars are often unmolarised.
- a simple stomach.
FAMILY SUIDAE
: THE PIGS
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XH19-4.1 Wart hog
(Phacochoerus
æthiopicus) skull.
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The wart hog skulls show typical suid features. Both
the upper and lower canines point upwards. The teeth are low-crowned
relative to tylopod and ruminant artiodactyls.
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A wart hog and piglet, East
Africa.
Wart hogs use their tusks in defence, and
will have to defend their young from attacks by the many
canivores found on the African savannah.
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Lateral toe reduction is less pronounced than in the peccaries.
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A warthog feeding.
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Pigs are generally omnivorous, and are commonly found
in forested habitats. Pigs have been known to eat leaves, seeds,
roots, fungus, fallen fruit, grass, insects, birds' eggs, lizards and
small mammals. Also, pigs are commonly active at night.The wart hog
is one exception, it grazes on the African savannah and feeds on
roots. It is only active during the day and will spend the night in
dens, usually the abandoned burrows of other animals.
The tusks are used for defence and in conflict
between males. The more prominent upper canines are primarily for
display. Most damage is inflicted by the sharper lower canines. The
facial warts that give this pig its name help protect the face during
these conflicts.
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Two skulls of
Sus scrofa,
the domestic pig.
The differences between the two skulls are
attributable to selective breeding by humans.
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A babirusa (Babyrousa
babyrussa) 'snuffling' along the
ground.
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Pigs have a superb sense of smell and can easily
locate food buried underground. The lead edge of the snout is
hardened and used to dig with. The tusks are not used for
digging.
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A babirusa.
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FAMILY TAYASSUIDAE: PECCARIES
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XH19-21.2 Collared peccary (Tayassu tajacu) skull
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Similar to pigs, peccaries differ from their close
relatives in a few ways:
- further reduction of the 2nd and 5th toes.
- the upper canines point down.
- the stomach of a peccary has 3 chambers.
The peccaries became separated from other swine by
crossing to the New World in the Oligocene.
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A collared peccary
(Tayassu
tajacu).
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There are three living species of peccary, the rarest
of which is the chacoan peccary of the Andes (
Catagonus wagneri),
only 'discovered' in 1975. All three species of peccary alive today
are fairly similar. They are all omnivorous, with a similar diet to
the pigs in the Old World. Peccaries also have a very sensitive snout
and they will use their tusk-like canines to cut roots.
Peccaries are found in a variety of habitats in their
range extending throughout South America and the southern portion of
North America, including scrub, grassland, tropical forest and thorn
forest.
All species travel in herds of varying sizes and show
cooperative defence.
The peccary is hunted for meat, but the greatest
threat to its future is habitat loss.
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A collared peccary.
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Compare the general shape of the peccary above with
that of the tapir, a perissodacyl also found in the forests of South
and Central America. Both are stocky, with short legs and a blunt
snout.
FAMILY HIPPOPOTAMIDAE:
HIPPOPOTAMI
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A hippoptamus
(Hippopotamus
amphibius) from Africa.
Hippopotamuses are rarely seen out of the water
during the day but must leave their pools at night to graze.
Because their broad lips are so efficient at grazing, the
vegetation close to their pools is often completely removed,
so hippopotamuses must often travel a few kilometres in
search of food. They will often use and wear out the same
path every night.
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Hippos have short legs with broad, four-toed feet to
support their substantial weight and prevent their feet sinking too
deeply into the mud.
Most hippopotami, including extinct forms, belong to
the genus Hippopotamus.
Presently found only in Africa, Pleistocene hippos were found in
Eurasia.
The skull shows typical hippopotamid features:
- eyes set high in the skull (common in aquatic
animals).
- a deep lower jaw.
- enlarged, tusk-like canines and incisors.
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A pygmy hippo
(Choeropsis
liberiensis) yawning.
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A hippopotamus paddling in an African
lake.
Notice that the the ears, eyes and nostrils
are all on the upper surface of the head, allowing the
hippopotamus to survey its surroundings while exposing as
little of its head as possible.
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Hippos are found in pools, rivers and wallows during
the day but emerge to graze at night. Hippopotamuses can walk along
the bottom of rivers and pools on the tip of their feet. The smaller,
more primitive pygmy hippo (Choeropsis
liberiensis) is found in forested areas of
west Africa.
Pygmy hippopotamuses spend less time in the water,
but their sensitive skin is at less risk from the sun because they
live in dense tropical forests.
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A pygmy hippo.
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The hippo is at risk from the effect of climate
change on its watery refuge. If the African climate becomes drier the
pools and rivers will dry up, leaving hippos homeless.
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A hippo mother and calf.
Gestation lasts 240 days, and the calves are
suckled for 8 months.
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Male hippopotamuses hold territories where they keep
'harems' of females. Groups of males, their females and calves can
number nearly 150 animals.
Pygmy hippos lead a solitary lifestyle. The only
social group they will be found in is a mother with her calf.
Two pygmy hippopotamuses:
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