Posted by: James Wapotich | March 9, 2015

Trail Quest: Herpetology Walk with Samuel Sweet

In March 2015, Dr. Samuel Sweet led an afternoon hike at Arroyo Hondo to search for reptiles and amphibians and shared his expertise. The walk was hosted by The Land Trust for Santa Barbara County, which manages the preserve.

The hike followed the main trail up the canyon, and as the group approached a wooden fence along the trail, the first lizard was spotted.

Dr. Sweet captured it with a noose on a long slender stick, similar to those fashioned from wild grass you may have seen kids use. He explained that lizards don’t weigh enough for them to be harmed by the experience. He then put the lizard in a clear, plastic container with air holes, and passed it around.

Dr. Samuel Sweet UCSB herpetology reptiles amphibians arroyo hondo walk

Dr. Sweet, tools in hand, searches for lizards

The specimen was a Western fence lizard, also known as a blue-belly lizard, because of the blue scales on their belly and throat. The lizard also has blue scales on its back, as well, and can change appearance by revealing or concealing those underlying blue scales.

In terms of overall color, large adult males tend to be black, while females and juvenile males are tan or brown. The females, unlike the males, stop growing once they reach maturity, channeling that energy instead into reproduction.

If you’ve seen blue-belly lizards, you may have wondered why they’re doing all those push-ups. “When they do their push-ups, another lizard can see that blue color.” Dr. Sweet told the News-Press. “They’re showing off that they own a particular piece of territory, and if it’s a good enough piece of territory, a bunch of females will like it and come and mate with them.”

Western Fence Lizard Blue-belly

Western Fence Lizard aka Blue-belly Lizard

He also explained that each species has its own unique head-bobbing pattern and can tell one other apart based on the pattern.

When holding the lizard, Dr. Sweet was careful to pin just one leg between his thumb and finger, rather than grasping it, allowing the lizard to “imagine that it’s still winning”, which helps keep it relaxed.

The next lizard that was caught was an alligator lizard, which Dr. Sweet pointed out are actually very different from blue-belly lizards. There are two major groups of lizards: those that rely more on visual information and those that rely on olfactory information.

For example, alligator lizards, which rely more on olfactory information don’t change color or make showy displays. And instead, prefer to remain hidden and mark their territories with scent. Another difference is in the way they hunt. Lizards that rely on visual information, such blue-belly and horny toad lizards, wait until their prey moves and then catch it, whereas lizards that rely on olfactory information track their prey by smell.

Another feature Dr. Sweet pointed out was the ticks attached the lizard. Ticks attach themselves to both blue-belly and alligator lizards, but what’s interesting is that antibodies in the blood of both species actually rid ticks of Lyme disease. That is, the antibodies counteract the bacteria that causes Lyme disease, effectively curing the tick.

Southern Pacific Rattlesnake

Southern Pacific Rattlesnake

As the walk continued, one of the participants spotted a rattlesnake resting in the brush. Using a potato rake that he carries on his walks, Dr. Sweet fished the snake out of the brush and placed it on the road for everyone to see.

The snake was anxious to return to the brush, but using the rake, Dr. Sweet continued to redirect it back to the middle of the road. The snake was surprisingly mild-mannered, and although at times rattled, did not try to strike.

“Rattlesnakes here are not very defensive, and don’t put on a big show. Most rattlesnakes you encounter locally will not even rattle, they’ll just sit still or leave.” Dr. Sweet observed. ”That changes if you go out to the Carrizo Plain or the drier parts of California, where they get upset pretty easily. In those places, they’re much more exposed.”

He also noted that the venom of Southern Pacific rattlesnakes typically isn’t fatal to humans and that there’s no advantage to the snake in wasting venom on humans that it could use for hunting, unless provoked.

Rattlesnakes are generally inactive from October through early March, and although not hibernating in the classic sense, tend to remain still, and only come out during that period if there’s a warm spell.

At several points along the hike, California newts where found in the stream. Although more toxic in other areas, their bright coloring is still a signal to predators not to eat them.

California Newt

A pair of California Newts

Newts can be found in the Santa Ynez Mountains from Hollister Ranch to near Lake Casitas, as well as in some of the year-round creeks on the back side of the Santa Ynez Mountains. Preferring wetter climates, their range in Southern California has become more limited since the last ice age, with the next nearest population to the south in the Santa Monica Mountains, and to the north in San Luis Obispo County.

A new threat facing newts, beside loss of habitat, is non-native crayfish, which eat the hatchlings or larvae before they’ve had a chance to develop their front and hind legs.

Other amphibians in our area are salamanders, toads and frogs. The most common native toad in our area is the Western toad, found throughout our local backcountry. Less common is the endangered arroyo toad, which has a much more restricted range.

The native frogs in our area include Pacific tree frog, California tree frog, and the endangered California red-legged frog. Pacific tree frogs come in a variety of colors, while the California tree frogs are typically grey.

At one point during the walk, Dr. Sweet went down to the creek, towards a place where he suspected he’d find turtles. Using a fishing net, he caught a turtle and brought it over to one of the picnic tables, and identified it as a male western pond turtle.

Western Pond Turtle

Western Pond Turtle

Western pond turtles are the only native turtles in our area, and the males have a thin, concave shell on their underside and a long tail so they can fit on top of the females in order to mate.

Although turtles here don’t hibernate in the classic sense, they will, according to Dr. Sweet, employ one of two strategies during the winter. In rivers, like the Santa Ynez River, they will either bury themselves in the cattail mats, or just lie in the deeper water, where it’s 10-15 feet deep, and stay there all winter. In canyons, like Arroyo Hondo, where winter rains can bring down huge boulders crashing through the creek, turtles will climb up the hillsides, and dig in under the brush, or under a wood rat nest, returning to the creeks when it’s time to mate.

The main threat facing western pond turtles, in addition to loss of habitat, is reproductive failure. “A single raccoon will spend all night looking for a pond turtle nest and usually find all of the eggs.” Dr. Sweet explained. “The problem is that raccoons are now supported by human garbage and radiate out for miles from where they get the garbage. And there’s just not enough predators like bobcats and mountain lions to keep the excess population in check.”

Raccoons will also try to eat turtles, sometimes managing to take a leg. Once a turtle reaches adulthood, however it’s only predator is bears, which have strong enough jaws to crack open the shells. Western pond turtles can live for 40-50 years.

A native of Connecticut, Dr. Sweet, attended Cornell University in New York, before attending UC Berkeley for his graduate studies. After college he was hired in 1977 by UC Santa Barbara; today he serves as a professor of Evolution and Ecology at the University. Since first moving to Santa Barbara, Dr. Sweet has also visited most of the local backcountry.

If you have questions regarding our local reptiles and amphibians, Dr. Sweet can be contacted at, sweet at lifesci dot ucsb dot edu.

This article originally appeared in section A the March 9th, 2015 edition of Santa Barbara News-Press.


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