Junk Piles Attract Snakes – and UA Researchers
By Janet Fox, May 14 2010
The truck lurches to a stop and the driver leaps out and heads purposefully towards a pile of discarded building material. Flipping over a piece of roofing, Phil Rosen quickly picks up a centipede in his gloved hand. Placing it in a glass jar he grins and says, “Snake food.”
Rosen is a herpetologist – a specialist in amphibians and reptiles – and a research scientist at the University of Arizona. On this April day, he is out “roadcruising” and “flipping cover,” herper lingo for driving around looking for animals crossing the road and sheltering under rocks, brush and, in this case, junk piles.
The truck bounces further down the rough dirt road in the Avra Valley area. Piles of discarded construction material, appliances, children’s toys and household trash litter this desert area, west of Tucson.
These dump sites appear to most people as a blight on the landscape.
But Rosen has a different reaction – the dumps are potential habitat for a number of animal species.
Rosen has found “quail, rabbits, packrats, mice, gophers, a skunk, lizards and every kind of snake” in these piles. He is particularly interested in the snakes.
In an as-yet-unpublished study done with colleague Peter Holm, he found banded sand-snakes were using the junk piles to hunt and to regulate their temperature. They were found under or near preferred pieces of such cover over many years.
Warm-blooded animals, like mammals and birds, keep their body temperature constant with internally produced heat energy. Snakes and other so-called “cold-blooded” animals rely on environmental sources of heat. The sun, the warm ground, and shelter sites help warm their bodies in preparation for hunting and foraging, or just to keep their bodily functions humming along.
The piles of dumped materials tend to warm up faster than underground burrows in the surrounding desert. So animals are drawn to the junk piles during early morning and evening, and on cooler days.
Even in the city, creating cover can give lizards, birds and other animals potential habitat and shelter from household pets. Piles of branches and leaves, for instance, can help lizards escape from cats.
Professor Michael Rosenzweig, also at the University of Arizona, endorses ways “to meet nature halfway.” He coined the term "reconciliation ecology," which refers to designing human uses of land to also support other species. Even urban areas can support biodiversity, if only we make the effort, according to Rosenzweig.
These junk piles around town aren’t “designed” to meet nature halfway, as Rosenzweig endorses. And, of course, it isn’t demonstrated that wild animals really need debris like this. But they do use it. A lot. And it does make them easier to find.
In the right season for snakes, “you can get 20 or 30 in a day or night,” Rosen said.
While cruising along the Santa Cruz River on another trip out to “flip cover,” Rosen spots the distinctive striped tail of a rattlesnake, just visible under an old tabletop. Despite “No Dumping” signs, there are piles of trash all around.
Rosen picks up the tabletop without hesitation and exposes a large diamondback rattlesnake sheltering under it. He skillfully handles the snake with a pair of tongs.
The snake is not aggressive. It is late afternoon and Rosen thinks it may have just come out from its den to warm its body for the evening hunt. He points to a packrat nest and mentions that it might have attracted the snake.
He measures the snake – it’s more than 3 feet long. While the centipede is destined to be a meal for a 6-year-old shovel-nosed snake he keeps, the diamondback is luckier. Rosen releases it and it quickly slithers into the bushes. Another day of flipping cover heads to a close.
Janet Fox is a field biologist and student of Geography at the University of Arizona. A mother and grandmother, she is interested in the effects of climate change and sustainability issues.