AMPHIBIANS IN HERCULES
Amphibians: from “amphi” (double) “bios” (life). Most have an aquatic
larval stage and transform into a semi-aquatic adult. Have been on earth
over 300 million years. Probably first vertebrates to spend part of their
lives on land. Very adaptable, live in many varied habitats including the
desert and the subarctic. Can tolerate cold but must have moisture
(desiccation = death). Desert species estivate during periods of extreme
heat. Most have lungs at adult stage but oxygen and carbon dioxide are
also exchanged through the skin. Cannot change their color, but can
change their shade which aids in camouflage.
Naked skin (no fur, feathers, or scales). Skin contains many glands,
produce defensive toxins (see
No claws on toes. Ectothermic: body temperature fluctuates with that
of the surrounding environment. Animals must move from place to
place to regulate their body temperature.
Most species return to some water source to breed and lay eggs. Larval
stages have gills and may exploit different food sources than adults.
Rates of development vary from species to species, some a matter
of weeks, others may take a year or longer. Lungless salamanders
such as slender salamander reproduce on land in moist woodlands
or stream-banks. Development is direct with no larval stage.
There is great concern among scientists about a worldwide decline in
amphibian populations. Some sites have reported a 50 to 90 percent
drop in numbers. Western species have been particularly hard hit. As
amphibians are an important part of many wildlife food chains
continued declines could have far-reaching consequences.
Animals found here are divided into two orders:
Salientia (Anura), the tailless frogs and toads;
and Caudata (Urodela) the salamanders.
Newts are a type of salamander.
FROGS AND TOADS
Adult frogs and toads are tailless. Frogs have smoother skin and larger
hindlimbs adapted for swimming and leaping. Toad skin is thicker, drier,
distinctive warts. Most species have a well developed ear (tympanum)
and use their voices to defend territory, attract mates, and signal distress.
All of the local species return to some body of water to breed. Fertilization
is external. Male fertilizes eggs released into the water by the female as he
clasps her (amplexus). Fertilized eggs hatch into tadpoles which develop into
froglets and toadlets.
Pacific Chorus Frog (Pseudacris regilla )
Size: Small (3/4 -
2"), climbing frogs. Toes have
wide, sticky tips with an
extra joint for flexibility. Various colors of grey, green brown, and tan.
Can darken or lighten color but does not change from one color to another.
Distinctive black eye stripe. Call is a very loud “Kreck-ek”.
Habitat: Found in marshes, ditches, ponds and streams in grassland or
wooded areas. Common in backyard gardens. Nocturnal and diurnal.
Common throughout most of the year except during exceptionally dry
or cold periods.
Reproduction: Eggs are attached to vegetation in shallow water during
January to July breeding season. Males arrive at breeding site first where
their calls attract females.
Food: Adults eat insects, spiders, isopods, and snails. Tadpoles eat
vegetation and small aquatic life, and are in turn food for a variety of
Red-legged Frog (Rana aurora dray tonii )
Size: 2 - 5". Brown to reddish color on back with dark flecks and
blotches. Red on belly and underside of legs. Dark mask bordered
by pale jawstripe. Well-defined ridges (dorso-lateral folds) extend
from behind the eye down the length of the back. Hind toes are
webbed. Males are smaller than females.
Habitat: prefers sheltered aquatic areas but also found in damp
woodlands. During winters it stays in mud at the bottom of ponds and streams
breeding season. Nocturnal and diurnal, also very shy. Weak guttural,
stuttering call is most commonly heard during the breeding season.
Reproduction: Irregular, grape like egg masses up to 10" across
are attached to vegetation in shallow water during short (1-2 week)
breeding season from January to May.
Food: Insects, isopods and possibly other small amphibians. This frog
a favorite prey of the endangered
species are declining in the Bay Area.
Now listed as threatened on the Federal Endangered Species list.
Western Toad(Bufo boreas)
Size: 2 1/2 - 5". Stout, short legged and warty. White or cream colored
mid-dorsal stripe. Dusky colors of gray, brown, or green above with
warts surrounded by dark blotches. Stripe may be weak or absent in
juveniles who also may have bright yellow patches under their feet.
Oval paratoid glands behind eyes. Males in breeding condition develop
dark nuptial pads of slightly roughened skin on the inside of one or
more fingers. Males have a weak chirping voice because they have
no vocal sac. Females are voiceless.
Habitat: Variety of habitats including gardens, grasslands, woodland
meadows, ponds , springs, and slow moving streams. Nocturnal in
warm areas, diurnal at higher elevations. Their thick warty skin allows
them a more terrestrial existence than frogs although they will retreat
to rodent burrows if the temperature rises. Unlike frogs, who can leap
out of danger, toads will rely first on camouflage. If this fails the toad
will face the predator head on. A bite on the toad’s head will release the
irritating toxin stored in it’s paratoid glands into the predator’s mouth.
The bad taste and subsequent nausea discourage most from taking a
second bite. Toads can be very long-lived, with captive specimens
surviving 20 years or more.
Reproduction: Jelly- like strings of eggs (up to 16,000 per female) laid
in shallow water during breeding season from January to July.
Food: Insects of all kinds, crayfish, sowbugs, snails, slugs, and
occasionally other toads.
Salamanders are lizard-like in
body shape but lack scales or claws and have soft, moist skin.
Slow moving. Most species are terrestrial, spending all but the breeding season seeking out
the protection of rodent burrows, logs, and moist vegetation. Most return to
natal ponds and
streams to breed. Fertilization is internal; the male provides a spermatophore which is
picked up by the female and stored in her cloaca. Fertilized eggs are laid in shallow water
attached to rocks or vegetation. Young have gills during aquatic larval stage, develop
over 1 or 2 seasons and disperse into woodland retreats. The lungless salamanders
such as ensatina, slender salamander and arboreal salamander are completely terrestrial.
Eggs are laid in moist, protected spot and, in some species, guarded by the mother until
they are hatched. Development is direct, with no aquatic larval stage. Young are small
versions of the adults.
Size: 2 1/2 - 3 1/2". Brown above, yellow to reddish
lower eyelids, larger eyes and different tooth pattern than rough-skinned newt. Breeding males
have smooth skin, a flattened tail, swollen vent area, and dark nuptial pads on the underside of the feet.
Habitat: Grassland, woodland, and forest. During most of the
year these newts are terrestrial. Skin
is rougher and thicker than most salamanders and they are commonly seen during the day. Logs, rocks
and rodent burrows provide shelter during extreme conditions. Generally safe from predators
because of skin secretions of tetrodotoxin, one of the most toxic substances known. Also found
throughout the flesh and internal organs. Minute amounts can cause paralysis and death in most
vertebrates. If disturbed, newts will assume a “defense posture” which exposes the bright colored
ventral area, presumably as a warning to predators.
Reproduction: Migration to breeding sites begins during the first fall rains. Breeding takes
place from December to May, reaching a peak from February to April. Remarkable homing
ability; newts displaced several miles will still return to the same section of the stream in
which they were spawned. Prefer streams or ponds with rocky beds and tree roots or
other vegetation for cover and egg attachment. Eggs of both species are similar, but
rough-skinned are laid singly while the
hatch from eggs in approximately 4 weeks. Some transform by the end of their first summer.
In cooler areas may remain in the water for another season. Sexually mature at two years
although adults do not necessarily breed every year.
Food: Insects, earthworms, crustaceans, spiders, slugs, amphibian eggs. Larvae
eat insects and aquatic insect larvae, crustaceans, and also scavenge.
Arboreal Salamander (Aneides lugubris)
Size: 2 1/2 - 3 1/2". Brown above with pale yellow spots of varying sizes, tail somewhat
prehensile. Young are clouded, with gray speckles and brassy patches.
Habitat: Primarily oak woodland. Found in hollows, under bark, inside rotting logs or
wall crevices. During summer months may congregate in moist tree hollows high above
the ground. Nocturnal. Active on the ground November to May, except during extremely
cold or dry spells. Lungless, breathes through moist, thin skin which is very smooth. Good
sense of smell which may assist in locating a mate. Adults can bite.
Reproduction: Eggs laid in arboreal or terrestrial sites and guarded by adult. No free
living larval stage, development is direct.
Food: Slender salamanders, insects, centipedes, spiders, sowbugs,
and possibly fungus.
Santa Cruz Black Salamander (Aneides flavipunctatus
Size: 2 5/8 - 3". Uniformly black above and below, sometimes with very small flecks. Young: above
black, limb bases yellow.
Habitat, Reproduction & Food: Same as Arboreal Salamander
Range: Coastal Mountains of San Mateo, St. Clara & St. Cruz counties
Size: 3-5 1/2". Very long body and tiny legs.
Sometimes called a worm salamander.
Only 4 toes on each foot. Dark above, with broad yellow, brownish, or reddish band
on back; colors may vary with locality. Belly dark, fine specks of white.
Habitat: Grasslands (with trees), chaparral, woodland, forest
and gardens under logs,
boards, leaf litter and streamside rocks. Size and shape allow it to make use of termite
and earthworm burrows. In defense it will coil like a watch spring and thrash violently.
Tail may detach if handled roughly. Lungless, terrestrial.
Reproduction: Breed in late fall and winter during rainy season. 4-21 eggs often
laid in communal nests, young emerge in winter and spring. No
aquatic larval stage,
Food: Earthworms, small slugs, mites, spiders, and
small insects such as aphids, ants, flies, and small beetles.
Ensatina (Ensatina escholtzii)
Size: 1 1/2"-3". Smooth skinned with a swollen looking tail which is
constricted at the base.
Much color variation, but most have yellow or orange limb bases. Male has enlarged upper lip
and longer, slimmer tail than female.
Habitat: Common in coast redwood, oak woodland, and old chaparral as long as shade
and rotting logs are available. Also make use of woodrat nests and rodent burrows.
Lungless, terrestrial, and primarily nocturnal.
Reproduction: Mates from October to March. Most lungless salamanders engage in
courtship behavior. Males rub and nudge females who straddle the male’s tail. A
spermatophore is deposited, taken up by the female and stored in her cloaca.
Eggs are laid in secure underground sites or under bark or rotting logs. Female broods
eggs. Development is direct, gills are lost at the time of hatching. Young hatch in summer or fall.
Food: Insects, earthworms, centipedes, spiders and sow bugs.