The Search for the Secretive Black Legless Lizard

Black Legless Lizard

This story by former intern Christine Schelin in the Fall issue of Tideline, the quarterly newsletter of the San Francisco Bay National Wildlife Refuge Complex.

Careful to leave the San Francisco Bay National Wildlife Refuge Complex Headquarters by 9:00am, my fellow intern and I grab the black legless lizard backpack and head for the Jeep. The drive to Salinas River National Wildlife Refuge, located twelve miles north of Monterey, takes approximately one hour and forty-five minutes. The black legless lizard backpack does not refer to a brand name for hiking gear, but refers to our all important bundle of equipment needed for our monthly black legless lizard surveys. The equipment list includes: a ruler, small plastic bags, garbage bags, thermometer, compass, color chart, clipboard, and data sheets. With our inventory checked, we are ready and hopeful for success in our search of the secretive black legless lizard, also known as Anneilla pulchra nigra.

Rumbling down the dirt road, we head into Salinas River National Wildlife Refuge. Waving to the occasional fisherman, walker, and beach-goer, we scan the refuge entrance. A steady breeze cools the air as the sun hides behind the clouds. Black-necked stilts, American avocets, brown pelicans, and gulls are a few of the birds filling the landscape. After we park, the ritual begins: I lather on sun-block, put on my wide-brimmed hat, tie my jacket around my waist, and take one last gulp of water. As my partner finishes his routine, we continue to head down the gravel road on foot, which leads to the beach. For us the beach will have to wait until our surveys are completed. We veer left off of the road and walk up the back dunes. Careful not to step on any native plants, we zigzag up the dunes heading to our first stop in search of black legless lizards.

The black legless lizard, as well as the silver legless lizard, both of which are found at the refuge are subspecies of the more common California legless lizard, or Anneilla pulchra. The first requirement of an intern searching for the black legless lizard is knowing what they look like. The black legless lizard, as you might imagine, looks a lot like a snake, it lacks any limbs or ear openings, and has smooth scales. Unlike snakes, black legless lizards have moveable eyelids and are able to detach their tails to escape from predators.

Adult females give birth to approximately two to three offspring once per year, and baby black legless lizards are live-born and are approximately two-and-a-half inches in length. 

Black Legless Lizard in HandThe adults have the width and body length of a new pencil. The black legless lizard’s dorsal, or topside, is blackish-brown in color while their ventral, or underside, is a bright, mustard yellow. This lizard species has adapted specifically to subterranean life. It rarely ever surfaces with the exception of searching for food. With their small heads and sleek bodies, they can successfully travel below the surface of their sandy environment. 

Fortunately, we are not required to comb their entire dune habitat at the refuge, which encompasses approximately 32 acres. In April of 1997, when the black legless lizard survey began, 30 wooden two-by-two foot plywood cover-boards were placed strategically in the back dunes. The cover-boards, distanced several yards apart, provide a slightly moist and cooler site for the lizards on warm sunny days. The insects, larvae, and spiders that are food to the black legless lizards can be found under the boards enjoying the provided shelter. As we lumber up the dunes, our eyes seek board number 50101. It doesn’t take long until we spot the cover-board partially hidden by vegetation. 

Hoping not to scare off a black legless lizard, we move in quiet anticipation as we prepare for the search under our first board of the day. I take out the compass, thermometer, and data sheet from our special backpack. My fellow intern clambers up the nearest dune peak and takes the first compass reading. His determines the direction of the wind. 

Meanwhile, I hold out the thermometer and check the air temperature. The moderately gusty wind is coming from the southwest, as usual, and the air temperature reads a cool and comfortable 19 degrees Celsius. With these two readings we are ready. I crouch down in front of the board, while my colleague kneels at my side with the data sheet and 

Black Legless Lizard Surveypen in hand. Every lift of a black legless lizard cover-board exposes unsuspecting critters to the sunlight. In prior surveys, we have screamed once or twice when we aroused a surprised mouse, or grimaced at the strange Jerusalem cricket. As I gently lift the cover board and lean it against the vegetation, we notice the more typical scene which includes: ants, various arthropods, and an occasional spider. We take note of the inhabitants of cover-board 50101 on the data sheet.

This time, a black legless lizard was not waiting for us on the surface of the sand. I shove the thermometer in the now exposed sand to determine the temperature. Careful not to leave any area unturned I penetrate the sand with my fingers and continue to reach into the sand until the resistance is too great. As I slowly pull out my hands, I let the sand sift through my fingers. It is in this way we hope to uncover the black legless lizard. I continue my search in this manner for the entire area that was covered by the board. Careful not to miss any black legless lizards I sift through the area one more time.

Reaching into cool, moist sand with the ocean air fanning the surrounding vegetation, I often wonder what will become of this mysterious species. Once considered for the Endangered Species List, the black legless lizard population was found to be in higher numbers than predicted. Therefore, the proposal to list the species was withdrawn in 1998. Nonetheless, as the black legless lizard is only found in the coastal sand dunes of the Monterey Bay region, its fate is uncertain. Coastal development has caused the disappearance of much suitable habitat for the black legless lizard. We feel the continued monitoring of this species is a necessity for its long-term survival. 

We make our way to the next board tucked away behind a dark, green mock heather plant. Board number 50102. Maybe this covers the hiding spot for our sought after prize? With no discovery under cover-board 50102 and with our lunch break taken, the early afternoon quickly passes. Next, we approach cover-board 50201. My fellow intern takes his turn at sifting the sand. Suddenly, in his hands wriggles a stunning black legless lizard. Excitement sets in as we scramble for a small plastic bag in which to place the lizard. Quickly he finishes sifting the rest of the sand. We take out our required instruments and gently take the lizard out of the plastic bag. The length of the lizard is measured from the snout to the vent, and also from the vent to the tail end. We inspect the tail end to note if this lizard has recently lost its tail.

Measuring Black Legless LizardTheir strength is amazing. It tries to push and burrow into the crevasses of my cupped hands. Taking out the color chart, we determine the lizards particular shades of dorsal and ventral color. Firmly wrapping its tail around my thumb, I stare into its small, deeply set dark eyes and admire its perfectly evolved form. Smooth to the touch, the black legless lizard’s design permits it to skillfully burrow through sand in search of food. This particular black legless lizard has so far managed to avoid being eaten by his enemies: the alligator lizard, and several types of snakes, birds, and small mammals. 

With all of the necessary information gathered, we each hold the lizard for one last time. I feel honored to release this creature back into its sandy world. Seconds after its release, we watch as it forces its snout down into the sand. Rapidly, the lizard weaves its body from side-to- side until it has completely disappeared. After the thermometer is withdrawn and the sand temperature recorded, we carefully re-position the cover-board. By 3:00 p.m., the 30 cover-boards are surveyed. Our total count is one black legless lizard and one silver legless lizard. Standing on top of the dunes, I pause for a moment to take in the scene. I look out toward the ocean and listen to the calls of the shorebirds before we hike to the beach ahead.

The dunes at the Salinas River National Wildlife Refuge provide habitat for the continued survival of the black legless lizard. As we walk through the dunes toward the beach, it is obvious that much work is needed to ensure that this Refuge continues to be suitable habitat for the black legless lizard and other native wildlife. Heading to the beach, we periodically stop to remove persistent nonnative ice plant and New Zealand spinach, as well as, accumulating trash. Once we reach the beach, we walk along the shore and hope to spot the threatened snowy plover. As we return up the dirt road toward the Jeep, I am heartened by my contribution to the protection of a unique habitat and the wildlife that it supports. 

Christine Schelin was a refuge intern and volunteer at Don Edwards San Francisco National Wildlife Refuge.