The first day of autumn has been a red letter day in our yard. Not only was there a Western screech owl calling last night — a new species for the yard, as far as my observations go — but this afternoon, in the heat of the day, a young Desert iguana raced under a creosote bush in the front yard, when I went out to get the mail.

I whipped out my tiny Canon Elph but the little ‘zard was all warmed up from hanging out in the midday sun, and it sped away before hiding in the shade under the creosote where I could see him but couldn’t get a picture. So I pinched this nice photo by Jason Penney from the excellent Reptiles of Arizona website which you can check out for more detailed info about this lizard. When full grown, Desert iguanas (Dipsosaurus dorsalis) are large lizards — almost 6″not counting tail and up to 16″with it — with a blunt face, long tail, and distinctive buffy coloration below a colorful pattern of speckles. This little guy shone pale gold as it raced across the cement driveway; its color gave away its identity even before I got close enough to see him well. Tiger whiptails (Aspidoscelis tigris) the lizards we see most often around here, are darker and lower to the ground.

The little iguana was also exhibiting another trait of its kind: it was out in the hot part of the day, when most other lizards have retired to shaded shelter or underground to rest and digest their forage. Diet is another thing that makes Desert iguanas distinct from our other lizards — they’re largely herbivorous when mature, eating a variety of desert vegetation, including the yellow flowers of creosote bushes, which they will climb to feast on. The first Desert iguana I ever saw was among the spring wildflowers at the Desert Botanical Garden, grazing in the hot sun like a small-scale reptilian cow, even leaving behind it large (for a lizard) fibrous pellets of poop like plant-eaters do. And, yes, they are related to their better known cousins, the Green “Tastes Like Chicken” Iguanas (Iguana iguana) of Mexico and Central America. I don’t know what something that feeds on pungent creosote blooms would taste like.

But this is why seeing him was especially exciting: there are only a few in the neighborhood, and that number appears to be shrinking, at least by informal observation. It’s only a theory, but mortality of Desert iguanas (specifically in our neighborhood) seemed to accelerate after the City re-coated our streets with a dark sealant. It makes for good basking, perhaps, the dark surface heating up earlier and staying warm later than the old gray road, and sadly, for several weeks, I would see Desert iguana roadkill regularly: three along one stretch of a heavily-used street nearby alone. So, seeing this little guy who was perhaps this year’s hatch, or more likely a yearling, was a very welcome sight.

Etymological notes:

Dipsosaurus is constructed of Greek elements, meaning “thirsty lizard”; dorsalis refers to the spine, which in Desert iguanas is protected by prominent, keeled scales.

Tiger whiptail, photo by E. Shock

Aspidoscelis tigris: Aspidoscelis is also from Greek elements, and means “shield leg” because of the sturdy scales on the whiptail’s legs, and “tigris” because it is stripy.

My friend Kathy gave me a bucket of toads. Twenty five tiny toads, actually Couch’s spadefoots (Scaphiopus couchii) to be precise. Spadefoots are toadlike amphibians, with their own family, Pelobatidae (see etymological note below). They’re native to the Sonoran desert, and their reproductive cycle is timed to take advantage of summer monsoon rains, needing only 7-8 days to go from egg to tadpole to toadlet. In between monsoon seasons, the adults stay buried deep in the soil of sandy washes to keep from drying out. They can stay buried for 8-10 months at a time, until storms bring the right conditions for them to feed and breed. The sheep-like bleating of the singing male spadefoot is an archetypal sound of the Sonoran desert. Some Arizona tribes associate toads and owls with monsoon rain, and that’s the origin of the fanciful Three Star Owl piece “Two-Toad Owl“.

These little spadefoots hatched in a standing pool in Kathy’s Scottsdale yard, where they’re plentiful. They’re very tiny — each could sit on a penny. They’re so small that it wasn’t until I saw the close-up photos that their emerald green eyes were noticeable. If you’ve never nourished toadlets, they’re easy to feed: if it moves and fits in the toadlet’s mouth, they’ll eat it. These guys have been snarfing up crickets, and other protein-rich yummies like Miller moth larvae from birdseed (and an old bag of flour!). Even ants will go down the hatch, as long as it’s not one of the larger soldiers, which put off a noxious chemical. The one on the left was photographed before the first cricket feeding; it plumped up noticeably after downing a small cricket or two.

But I’m not keeping them in captivity. Once they’re fed up, I’ll release them in our yard at twilight, where hopefully they’ll replenish our neighborhood population. Releasing them after dark will give them a head-start over the foraging Curve-billed thrashers and Cactus Wrens. A couple years ago, we would hear male spadefoots bleating like lambs after a big rainstorm, and one or two would end up in the pool, looking for somewhere to breed. But recently, we haven’t heard or seen any. So I’m hoping these guys get things going again. Good luck, little spadefoots, and ‘ware Raccoons and Coachwhips!

Photos: the adult spadefoot photo is from the US Fish & Wildlife site on Arizona Amphibians. The other photos are by A. Shock. Excellent photos and still more info about Couch’s spadefoot can be found at Firefly Forest — check it out.

Etymolgical note and stray ornithological note

About the term “spadefoot”: It comes from the small, hard digging appendage on the underside of the back legs of these amphibians. Members of the family Pelobatidae are not considered “true” toads, so it’s proper to call them simply “spadefoots”. Pelobatidae, the family name for all Spadefoots, comes from a Greek word, pelobates (πηλοβατης), literally “mud-walker”. A nice tie-in for a potter is that the first element of this word comes from the Greek word pelos, meaning “clay”, specifically the clay used by potters and sculptors. The genus, Scaphiopus, is constructed of two Greek elements and means “spade-foot”. The species name, couchii, comes from the surname of Darius Nash Couch, a U.S. Army officer who, during leave in 1853/54, traveled as a Smithsonian Institute naturalist to Mexico, where he collected specimens of both the Couch’s Spadefoot, and Couch’s Kingbird, a tyrant flycatcher native to south Texas and the gulf coast of Mexico. Out-of-range Couch’s kingbirds occasionally show up in Arizona. Recently, a Couch’s kingbird has wintered in Tacna in southwest Arizona, eating bees and behaving like a tyrant flycatcher.

Spadefoot Update

All toadlets released tonight, in three batches around the yard, in areas with lots of cover, leaf litter, and access to sandy soil. Turns out there were about 30. They all hopped away dispersing almost instantly in the dark. They are hereby encouraged to eat earwigs and small cockroaches.

About horned lizards

Though sometimes called “horny toads” these reptiles are not toads at all but flat, round lizards which inhabit dry open areas of the western US and Mexico. They are especially well-armored with keeled scales, knobs, and yes, horns, making them look like little dragons. But they feel surprisingly soft when you pick one up, not unlike a beaded purse. (The grumpy-looking guy in the photo below is a Greater short-horned lizard E and I found trying to bask on a cloudy day on a ponderosa log on a backpacking trip in the Gila Wilderness of western New Mexico.)

Failing camouflage and flight, their ultimate defense from harassment is to shoot blood from their eyes. This isn’t an old wives’ tale like bats getting snarled in long hair — they really do it. It works pretty well, often startling the lizard’s captor into dropping it.

Horned lizards favor ants, especially of the genus Pogonomyrmex, Harvester ants, which comprise a generous portion of their food intake.

Most horned lizards lay eggs, but species like Short-horned which live at higher altitudes where the breeding season is too short to incubate eggs, give birth to live young — from 5 to 48 at a time!

These amazing animals have a specialized solar receptor under a clear scale on the top of the head. It’s called the pineal gland, and it’s linked directly to the brain. Although its function is not fully understood, it plays a role in the regulation of body temperature. The pineal gland has many features similar to the structure of an eye, though it is not linked to the optic nerve. Look for the small pineal gland on a Three Star Owl horned lizard bowl, indicated subtly on the top of the skull between the eyes.

Herpetologists currently recognize 13 species of Horned lizards, 8 in the US and 5 in Mexico.

My favorite horned lizard resource is the book Introduction to horned lizards of North America, by Wade E. Sherbrooke, UC Press 2003.

Horned lizard bowls from Allison Shock and Three Star Owl

I’m currently making horned lizard bowls representing two species, both native to Arizona and other parts of the Southwest: Short-horned lizards and Regal horned lizards. You can tell them apart by their horn configuration: Regals have an even corona of ten longish horns on the back of their skull, and Short-horns have 6 very short horns divided by a deep notch.

Both eat ants, so I depict Harvester ants in their bellies. The Short-horned is a live-bearer, so some have young lizards shown inside.

These bowls are handmade from stoneware, and fired to cone 5. Each bowl is different, and each scale is done individually by hand, as is the slip-painting in their bellies. There is no glaze on these pieces, but the mineral-pigmented slips are fired in place, and are indelible. Because of the lack of glaze, I don’t recommend them for frequent food use, or storing liquids. Primarily they are meant to be gazed at adoringly. Click here to see a picture of Horned lizard bowls on threestarowl.com.

It is a long thin snake.

Working this morning in the backyard, E heard the scolding of cactus wrens, thrashers and other regulars of our deserty neighborhood. He tracked down the source: a sleek and mottled coachwhip marauding, trying to take advantage of the monsoon “bloom” of young animals. Coachwhips (Masticophis or Coluber flagellum) are swift and tireless daytime foragers, searching the ground for favored foods such as lizards, and easily climbing our shrubby, tangled palo verdes looking for eggs and nestlings.

They are patterned cryptically, and look like the long braided látigo used by Mexican stockmen. (We called these whips “bullwhips” as kids — favored souvenirs of weekends in Ensenada, primarily used to harass each other.)

The coachwhip’s pattern is surprisingly cryptic, because like the Gila monster, it’s pink and brown, yet it still manages to disappear effectively against pebbly desert soils, and is nearly invisible even slung in the green branchlets of a palo verde, where it looks just like a rosy-brown dead branch lodged there. They’re not aggressive animals — although irritable might be the word — and they’re more likely to use their notable speed as a defense than to bite, unless handled. The Coachwhip actually earns the rattler-hunting reputation the Gophersnake enjoys less deservedly, and will eat anything it can catch and swallow, including other snakes, even rattlers.

More info on the Coachwhip here, at Tom Brennan’s excellent website on reptiles and amphibians of Arizona.