Salamanders: The World is their Oyster, or is it Wet Tree Trunk?
It’s winter in San Francisco, and the rains have provided some welcome moisture after a long dry summer and fall. On Mount Sutro this is a good time to catch a glimpse of one of our more reclusive residents, the salamander.
Photo by Lulu Aila-Unsworth
What is a Salamander?
Salamanders are amphibians that look like a cross between a frog and a lizard. Their bodies are long and slender; their skin is moist and usually smooth; and they have long tails.
Salamanders belong to the order Caudata, one of three orders in the Amphibia class. Caudata is a Latin term referencing the presence of a tail, which is a common denominator of all salamanders in all of their life stages. Salamanders are very diverse; some have four legs; some have two. Also, some have lungs, some have gills, and some have neither — they breathe through their skin. While salamanders vary widely in size (a tiny 2 inches to up to four feet long), most species on average are about 3-6 inches long.
Salamanders are a global phenomenon. They exist all over the world in places as far away as Iran and Siberia, but the largest number of salamander families can be found in the U.S.
Habits and Habitat
Salamanders are typically more active during cool times of the day and are nocturnal. During the day they lounge under rocks or in trees to stay cool. At night they come out to eat.
Salamanders come in a variety of colors; some with brightly colored spots while others are less flamboyant. According to research done by the San Diego Zoo, those with bright, colorful skin use this as a warning to predators to stay away. Many salamanders have glands on their necks or tails that secrete a bad-tasting or even poisonous liquid. Some can also protect themselves from predators by squeezing their muscles to make the needle-sharp tips of their ribs poke through their skin and into the enemy.
Salamanders can be found in a variety of habitats: from chaparral, woodland, grassland, and forests, to urban yards, vacant lots, marshes, and under beach driftwood. They are usually found in moist locations, under logs, rocks, bark, leaf litter, stumps, and debris.
A Salamander’s Place in our Environment
It’s not surprising that salamanders are important to the ecosystems around us. In many areas they are a critical food source for a wide range of reptiles, fish, birds, and mammals. Salamanders also eat substantial quantities of worms, snails, insects, and other invertebrates, influencing those populations, rates of organic-matter decomposition, and nutrient cycling.
Photo by Lulu Aila-Unsworth
Let’s Meet a Few of the Locals
Up on Mount Sutro there are at least three species of salamander observed. All of them are members of the family known as Lungless Salamanders (Plethodontidae). This means they respire through their skin and the tissues lining their mouth. They live in damp environments on land and move about on the ground only during times of high humidity.
California Slender Salamander (Batrachoseps attenuatus)
Size: 3 to 5.5” long
Color and appearance: Black or dark above, with red, brown, yellow, or tan coloring forming a dorsal stripe, sometimes with a herringbone pattern.
Its short limbs, long slender body with a narrow head and a long tail, give this species the worm-like appearance typical of most Slender Salamanders.
Where found: Endemic to California and extreme southwest Oregon.
Defense Tactics: Slender salamanders use several defense tactics including coiling and remaining still, relying on cryptic coloring to avoid detection; uncoiling quickly and springing away repeatedly bouncing over the ground, then remaining still again to avoid detection. It also detaches its tail, which wriggles on the ground to distract its predator while it escapes. Thankfully, the tail will grow back again later.
Yellow-Eyed Ensatina (Ensatina eschscholtzii xanthoptica)
Size: 3 to 6” long
Color and appearance: Orange-brown to dark brown above, with orange coloring below, on the eyelids, and on the sides of the head, tail, and body. A bright yellow patch on the eye gives this species its common name.
Where found: Yellow-eyed Ensatina is endemic to California, ranging from near Healdsburg in Sonoma County, south along the east side of the San Francisco Bay to Santa Cruz County. Ensatina is also the most widely distributed Plethodontid salamander in the West, ranging from Baja California, through much of California and continuing north into Oregon and Washington west of the Cascades Mountains.
Defense Tactics: When severely threatened, like the Slender Salamander, an Ensatina may drop its tail to distract the attention of a predator towards the writhing tail so the animal can crawl away to safety. The tail also contains a high density of poison glands. When disturbed, an Ensatina will stand tall in a stiff-legged defensive posture with its back swayed and the tail raised up and secrete a milky white substance from the tail, swaying the it from side to side. Rarely, Ensatina make a hissing sound, similar to the hissing of a snake, when threatened. (Stebbins 1951; Brodie, 1978).
Arboreal Salamander (Aneides lugubris)
Size: Up to 7 inches long
Color and appearance: Color is brown above with small cream to yellow spots. The undersides of the tail and feet are dull yellow.
Where found: Endemic to California and northern Baja California.
Defense Tactics: Arboreal salamanders resort to biting, a raised defensive posture, fleeing rapidly, and jumping. They are also known for making squeaking sounds when they are picked up or disturbed (hear the squeaking chips here). Both males and females are aggressively territorial. Individuals covered with scars (probably from fighting) are often found, and captives kept together often bite the other salamander's tail. Since the species is often found sheltering together in large numbers in dry weather, it appears that territorial aggression is not constant.
References
1) Facts About Salamanders. Alina Bradford. https://www.livescience.com/52627-salamanders.html
2) Salamander Species of North America. Terry Krautwurst. https://www.motherearthnews.com/nature-and-environment/salamander-species-zmaz07fmzpit
3) California Slender Salamander – Batrachoseps attenuatus; http://www.californiaherps.com/salamanders/pages/b.attenuatus.html
4) Yellow-eyed Ensatina - Ensatina eschscholtzii xanthoptica; http://www.californiaherps.com/salamanders/pages/e.e.xanthoptica.html#description
5) Arboreal Salamander - Aneides lugubris; http://www.californiaherps.com/salamanders/pages/a.lugubris.html