AMPHIBIANS IN HERCULES

 

Introduction

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.

 

Characteristics

Naked skin (no fur, feathers, or scales). Skin contains many glands,

some produce defensive toxins (see California newt and Western toad).

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.

 

Reproduction

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.

 

The Conservation

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.

 

Classification

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,

with 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

animals.

 

 

 

 

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

until 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

is a favorite prey of the endangered San Francisco garter snake. Both

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

 

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.

 

California Newt (Taricha torosa) 

Size: 2 1/2 - 3 1/2". Brown above, yellow to reddish orange below. California newt has light-colored
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 California newt lays an egg cluster. Gilled larva

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 niger)

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

California Slender Salamander

(Batrachoseps attenuatus)

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,
direct development.

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.

 

 

 

 

 

 

 

 

 

 

 

 

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