The Secret Life of Salamanders
By Jon Aull
One of the most amazing groups of animals to call Bidwell Park home is the salamander.
Salamanders have held people’s fascination for ages as the first land vertebrates, creatures who lead double lives, who can breathe air without lungs, who can walk through fire unscathed, and as ingredients for witches’ brews.
While salamanders may superficially resemble lizards, they are actually quite different animals.
Lizards, especially the blue-bellied Western Fence Lizard, are a common sight in the Park as they bask on sunny rocks. Salamanders are far more secretive. Both are cold-blooded, or ectothermic, which means that their body temperature is affected by the temperature around them. But while lizards are reptiles, salamanders are amphibians, maintaining a lower body temperature and preferring cool, moist places where they can keep from losing water through their thin, permeable skins. Unlike their reptilian neighbors, salamanders are active during the rainy season, going into aestivation, a sort of hibernation, in dry, hot weather. They spend the summer underground in rodent burrows, only emerging with the first steady rains of the season.
The word amphibian comes from the Greek word amphibos, meaning “a being with a double life.” This is a reference to the life stages of most amphibians, which are aquatic in the gilled larval form and terrestrial as adults. However, two of our resident species live their lives completely out of water. These two, the California Slender Salamander (Batrachoseps attenuatus) and the Ensatina (Ensatina eschscholstzii) are members of the Plethodonitae family. Members of this family are lungless and breathe solely through their skin. Both of these salamanders hatch underground out of eggs as miniature adults. The Slender Salamander is common in parts of Bidwell Park, but seldom seen. It can be found in shady places under leaf litter and logs. This two and a half inch long creature may appear to be a black worm at first sight. But closer inspection will reveal eyes and diminutive legs that look much too tiny for them. If you can get close enough, you will notice that they have four toes each on their rear feet, unlike other salamanders, which have five. When disturbed, it may coil up, then uncoil quickly, springing away and bouncing over the ground. Like other salamanders, its tail can be easily broken off, allowing the rest of the animal to escape a predator. The tail can regenerate, although this can take years.
It is a colorful 3-6 inch long salamander, brownish with reddish orange spots. It is nocturnal, so sightings are rare. It has an interesting defense mechanism, excreting a noxious sticky, milky white substance onto its tail to repel potential predators. When threatened, it arches its back and raises its tail as a warning.
One salamander that seems to be unconcerned about its fellow creatures is the California Newt (Taricha torosa) of the family Salamandridae, a brownish 5-8 inch long salamander with a bright orange underbelly.
This is the warty skinned salamander that you can find strutting that side to side salamander walk down the trail in Bidwell Park during rains. Another great place to see them is in Table Mountain creeks during spring wildflower season. During the late summer and fall months, this species has a terrestrial existence, hiding under logs and in rock crevices. After the first winter rains, the terrestrial adults, or efts, migrate back to their birth pools to breed. More the classic amphibian, these salamanders start their lives in the water as aquatic larvae. But not only do they metamorphose from aquatic larvae to terrestrial adults, they also undergo a transformation from terrestrial efts to aquatic breeders. The warty skin of the males becomes smooth and they develop a tail fin to aid in swimming. Their forearms enlarge into “popeye arms,” and their feet develop nuptual pads to more easily grasp the female while mating. Courtship involves a ritualistic dance in which the male will circle the female and rub his chin over the female’s nose. Several males may hang onto a single female, creating a “newt ball.” Eggs are laid in spherical gelatinous masses on vegetation or rocks in the water.
If threatened, they will push up their bellies and lift up their tails. If the predator attacks, the California newt excretes a neurotoxin through its warty skin and can cause paralysis and or death to its attacker. The poison is also toxic to humans and can be fatal if ingested, possibly explaining the use of newts for witches’ brews. Although they don’t have many native predators, introduced (exotic) predators such as mosquito fish and crayfish don’t seem to be bothered by the newt’s toxicity. Newt larvae appear to be especially vulnerable to these invasive predators. In addition to being poisonous, newts seem to have an almost supernatural ability to walk through low smoldering flames unscathed. Secretions on their skin foam up and help dissipate the heat from flames, which may protect them during forest fires.
As amphibians, salamanders have permeable skin, through which water and air pass readily.
With their sensitivity to pollutants in the air and water, amphibians are like canaries in a coal mine. Canaries were once used by coal miners as sensors (up until the 1970s in Britain) of poisonous gases such as carbon monoxide and methane, to which the canaries were more sensitive. The miners would take caged canaries into the mines with them and whistle to them while they worked. As long as the canaries whistled back, the miners felt safe. Amphibians are like those canaries. They are disappearing all over the world. Thirty-two percent of the world’s nearly 6,000 known amphibian species are threatened, and over 100 species have gone extinct since 1980. Even those that live in the wildest places on earth are disappearing, falling victim to acid rain and increased ultraviolet radiation from a thinning ozone layer. Locally, the California Tiger Salamander, a Threatened Species under the Endangered Species Act, is no longer found in the disappearing vernal pool habitat of Butte County. Although the California Newt’s sierran subspecies is common here, the coastal subspecies is a California Special Concern species. This is one more reason to appreciate the special place we have in Bidwell Park, a place that harbors a fascinating diversity of life.
For more information, check out Jackson Shedd’s Amphibians and Reptiles of Bidwell Park.