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Bush Vipers are fairly small snakes ranging
in adult size from Montatheris hindii
(8-14 inches) to Atheris nitschei
and A. squamigera (some specimens
may exceed 30 inches or 76 cm). They have broad heads, relatively
large eyes with vertical pupils, and narrow necks. Their bodies
are usually slender and have strongly keeled and overlapping
scales. The genus features an astonishing variety of colors
and patterns. Atheris ceratophora
and A. squamigera are particularly
variable species. Most Atheris
species are primarily arboreal, but may be frequently found
on or near the ground. The other three genera are terrestrial.
Bush vipers are endemic to Africa. Many species
have very limited ranges and exist only in isolated populations.
They range across equatorial Africa as far west as the rainforests
of Guinea (Atheris chlorechis)
and as far southeast as coastal Mozambique (Proatheris
superciliaris). They occur at a wide range of elevations
from lowland swamps (P. superciliaris)
to high altitude montane moorland (Montatheris
hindii). Rainforest, evergreen forest, montane forest,
upland swamp, and lowland swamp bordering grassland are among
the habitats utilized by species in this tribe.
A wide variety of small amphibians, lizards,
and rodents are eaten by bush vipers. Some species or populations
may feed predominately on small frogs, but bush vipers are,
for the most part, opportunistic feeders. There is some evidence
that some species may also occasionally consume snakes, snails,
or slugs. Many captive specimens will accept small mice. Cannibalism
has been reported in Atheris chlorechis
(Pareti 1994), Atheris squamigera
(Wallach 1980), and Proatheris superciliaris
(Broadley 1983). This may be aberrant behavior rather than
a normal feeding activity, but caution should be used when
housing snakes together especially during feeding. It should
be added that many keepers house bush vipers in pairs or groups
without incident. However, in Pareti's account of the western
bush viper cannibalism at the Audobon Zoological Garden in
Louisiana he describes the male being consumed by a female
approximately ten days after introduction into an exhibit
housing two females. This trio had been kept together for
about two months earlier in the year without incident. All
specimens had been feeding well on live mice. Cannibalism
has also been reported in the arboreal pit vipers Trimeresurus
and Bothriechis (Bridgeam
et al. 1990).
Arboreal bush vipers typically
ambush prey as they hang head down from a
branch, holding the prey animal until it succumbs
to the venom before swallowing.
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