Thursday, March 5, 2009

Alligator Gar

The molecules of air surged through the beast’s throat down a slippery tube and into the buoyancy bladder. Inside the membrane, blood vessels seine out the oxygen, maintaining a strategy that started perhaps 150 million years ago when this fish’s ancestors may have reptiled about the banks of a long ago sea. The mighty tail thrusts and propels it across the surface of the Rio Grande to lurk under a thicket of Giant Cane.

The largest Alligator Gar ever caught on a rod and reel came from the Texas side of the Rio Grande in 1951. At over seven feet long and 279 pounds, this marine leviathan ranks with the largest freshwater fish in the world.

The Alligator Gar has two rows of upper teeth and a powerful jaw both very much like the saltwater crocodile. A carnivore with a reptile-like ball and socket vertebrae and the ability not only take oxygen from the water with its gills but also to breathe out of water with a lung, this fish and its history have confounded scientists for years. Is it a fish trying to become a reptile, or a reptile that morphed into fishness?

Unusually well preserved fish fossils of the Green River, take the gar back over 100 million years ago, but new DNA research suggests this creature may have come from the Jurassic period or 150 MA. Either dating, the evidence suggests the fish has changed very little over the eons.

The diamond shaped interlocking scales that were once used by Native Americans for jewelry, breast plates and arrow tips, cover the fish in a tight armor and are part of the hydro-dynamics that make this fish a swift and great hunter.

The life span of an Alligator Gar runs 50-75 years but an increased mortality rate caused by pollution, dwindling habitat, and un-regulated fishing, is threatening the gar’s future. No longer found in the Upper Ohio Valley, many states have imposed bag limits. Texas and Louisiana still allow unlimited gar fishing, but in March, Texas Parks and Wildlife will host a public meeting to consider limiting commercial and sport fishers to one gar per day.

Dust Devils

A whooshing suck roared out of the earth as if some ginny had been released from the metallic fiber of the inner world. The spiral of dust and air danced across the field inhaling rocks, sticks, seeds and centipedes, a commotion unto itself on an otherwise hot and calm day.

Dust Devils, also known as Remolinos, in west Texas, are brief whirl winds that form when hot air from the earth’s surface rise unevenly, like bubbles in a Topo Chico. Cooler air rushes in to the column of hot air to fill the voids and the reciprocating air of unlike densities begins to spin. Slowly at first until, like the arms and legs of an ice skater tucked in tight for the encore, the atmospheric vortex of the dust devil becomes fully formed spinning at speeds of up to 70 mph and demonstrating the science principle of conservation of angular momentum.

As the vortex bops across the surface, more hot air is sucked in along with dust and debris, lowering the air pressure inside and causing the dust devil to rise. These augers of sand and dust can change colors depending on the landscape they run over and can even be transparent if formed over a clean grassy area.

Like tornados, they are weather phenomena, but most dust devils form under sunny conditions during fair weather and are seldom dangerous with few lasting longer than a minute. They generally form in arid and semi-arid regions and a flat barren terrain increases the likelihood of the hot air fuel. Diameters of three feet are common but some grow as large as 300 feet across the base, lasting thirty minutes and can lift more than 15 tons of dust and debris into the air. The whirling particles inside the vortex become electrically charged and create a magnetic field that helps lift more dust off the ground.

The Viking orbiters of the 1970’s, photographed Dust Devils on the planet Mars climbing out of craters, creating columns of Martian dust ten times higher than those found on earth.

Tuesday, March 3, 2009

Vinegarones

“Three bucks on the scorpion,” a bearded hombre waved his cash in the crowd as the greasy flow of the Rio Grande slapped at the pebbled banks of the island on which they stood.

“Got a buck here,” The dealer grabbed the bill from the bettor’s hand and moved to the next.

An iron tub had been dragged into this no man’s land somewhere between Texas and Mexico. As the sun dipped below the mountains the hawker announced the fight was about to begin: Two arachnoids faced each other at the bottom of the white tub, a tarantula and a vinegarone.

The vinegarone often referred to as a whip scorpion, is no scorpion at all, but an arachnoid, part of the spider family. With four pairs of legs, the vinegarone is nocturnal, and scoots across the desert surface at night in search of fresh meat, like crickets or millipedes. Like the scorpion, they have a pair of eyes in front and three on each side of the head, but have poor vision. To pick their way through the desert, they rely on their first set of legs. Modified over the eons, these legs act as antennae-like sensory organs, that feel the ground as they walk with the other six.

Many vinegarones grow as long as six inches, including the thin whip like tail, which is shaped much like the scorpion’s but without the poisonous barb. Vinegarones subdue their prey with a set of powerful pinchers.

The vinegarone when cornered is capable of spraying a mist of acetic and octanoic acid, a foul combination that smells like vinegar or vinagron in Tex-Mex and hence the name vinegarone.

In the scientific community vinegarones are known as Uropygids, meaning tail rump in Greek. Many varieities flourish throughout the world. The black sometimes orange Texas vinegarone is found primarily in the Chihuahuan Desert but has been found as far north as the Texas Panhandle.

Vinegarone was also the name of a railroad camp near the confluence of the Pecos and Rio Grande. At its peak in 1883, 3500 people lived there. Judge Roy Bean, who was also known as a vinegarone, operated a saloon there and occasionally hosted paramutual events on the un-lawed islands of the Rio Grande.