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(Bufo
cognatus)
| Identification: Skin with numerous small
warts; prominent ridges on top of head, diverging rearward from hard lump
on top of snout; loong glandular lump behind each eye; upper side with
somewhat symmetrical pattern of large, light-edged dark spots; often a
somewhat sharp-edged tubercle and a smaller dark-tipped tubercle on
underside of hind foot; head and body length of females up to 114 mm (4.5
inches), males usually less than 95 mm (3.7 inches.
Mature male: Dark, loose throat skin and dark patch on inner surface of innermost toe of front feet during breeding season; expanded vocal sac large, long, may extend upward in front of face. Juvenile: Warts reddish .
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Breeding call : A long, continuous trill
or pulsating ringing sound (at close range, similar to ear-splitting sound
of jackhammer) lasting at least several seconds; varies somewhat with
temperature and size of male; loud nasal quacks sometimes precede trill
(San Luis Valley).
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Larvae: upper side
initially blackish, then becomes paler and mottled brown and gray dorsally;
under magnification, dark upper skin may have an overlying golden suffusion;
pattern of large paired blotches appears on upper side before metamorphosis is
complete; eyes high on head; upper tail fin highly arched; fins clear with some
black lines, mainly in upper fin, sometimes extensively mottled in upper and
lower fins, or upper fin heavily pigmented and ventral fin clear or very
sparsely pigmented; muscular part of tail lacks an unpigmented band along the
lower margin; upper jaw strongly arched; usually 2 rows of tiny teeth on upper
lip, 3 rows on lower lip; third tooth row on lower lip (i.e., the one farthest
from jaws) considerably shorter than first row on lower lip; usually less than
30 mm (1.2 inches) long, but up to at least 35 mm (1.4
inches).
Eggs: usually in a single
row in long strings of two-layered jelly that is constricted between the eggs;
partitions separate eggs from each other; usually laid in shallow
water.
Colorado Distribution:
Eastern Colorado and the San Luis
Valley. Locally common.
Habitat: Plains grassland, sandhills,
agricultural areas, and semidesert shrubland.
Life
History: Breeds mainly in late spring and
early summer, in pools, ponds, and reservoirs filled or enlarged by heavy rains
or flooding. Larvae metamorphose into small toads usually 2.5-5 weeks after the
eggs were laid.
