I've spent the last two weeks going through the archives of ten years of Geotripper. I've been enjoying picking out a few bits here and there that I really enjoyed writing. One of these was the story of the toughest fish in the world, and the very surprising place where it is found. This was posted on February 19, 2015...
What kinds of fish are tough? Some Marlin that you spent a couple of hours trying to reel in one time in Mexico? A nice two pound Rainbow Trout that fought hard against your fishing skills in a mountain lake in the Sierra? Some Small-mouth Bass in a reservoir somewhere? I doubt any of them can stack up to this little fish. They were out and about last week during our field trip in numbers I haven't seen in some time.
It's little, hardly exceeding two inches in length. It's certainly not big enough to take a hook. It doesn't have a mouthful of teeth, and it's not a predator (unless you are a diatom or a clump of algae). So how is this a tough fish?
Consider this: it lives in water that can sometimes exceed the saltiness of seawater. By three times. I don't think there is another fish in the world that can do that. And...it can survive in water where the temperature exceeds 100 degrees. Again, I don't think there is another fish in the world that can do that. And one more: the environment in which these fish live can reaching freezing on occasion. No fish that I am aware of can survive such extremes.
But these little fish can.
On top of everything else about this species is the place where it lives,
the last place one would even think of looking for fish: Death Valley in
eastern California. The hottest place in the world, and the driest
place in North America.
Meet the Death Valley Pupfish (Cyprinodon salinus salinus), sometimes known as the Salt Creek Pupfish. It is just one of nine or so species and subspecies of fish that survive in the Death Valley region.
Once you realize that fish are living in Death Valley, certain questions are bound to arise. How can there be water enough for them to survive? How did they get there? And how did there come to be so many species and subspecies ?
The first question is perhaps the easiest to answer. It is true that rain almost never falls in Death Valley, with an average year seeing no more than 1.5-2 inches of precipitation. But Death Valley is the lowest ground in North America, and groundwater flows towards the valley, in some cases from a hundred miles away. Springs and pools form when faults or rock barriers force the water to the surface. These water sources don't depend on the rare rainstorm. It's thought that the water flowing from springs at Furnace Creek or Scotty's Castle has been underground for more than 10,000 years. These stable springs and pools have provided a secure source of water since the end of the last ice age around 12,000 years ago.
But how did the fish get there in the first place? We can say that the fish did not arrive under current climate conditions. River connections between fault basins could only occur during the ice ages when glaciers covered about 30% of the Sierra Nevada. Glacial meltwater drained into the Owens Valley and spilled over into other desert valleys, filling them, and ultimately filling even Death Valley with a hundred mile long freshwater lake. At some point, a connection was made with the Colorado River, and numerous species of fish invaded the ecosystem. But then the ice ages ended.
The vast lakes began to dry up, and the fish were forced to adapt or die out. A number of trout species survived in the cool waters of the Carson, Walker and Truckee River drainages, but in Death Valley, it was only the Cyprinodon species. The one species was forced to survive in different environments, water that might be fresh, salty, hotter, or cooler. The single species diverged into many, much as the finches of the Galapagos Islands did.
During the spring, the Salt Creek Pupfish expand rapidly into the growing flow downstream. Hundreds of fish become thousands, then a million or more. Most of them are doomed when the extreme summer heat sets in and Salt Creek mostly dries up. A few find refuge in the pools and springs at the head of the shallow canyon (a canyon that exists on the floor of Death Valley because of faulting).
Other species of pupfish are more severely limited. The Devil's Hole Pupfish is restricted to a single cavern opening only a few tens of feet across. It is said to be the most endangered vertebrate species in America and maybe the world. There have rarely been more than 300, and at times the population has dipped to barely two dozen. Their continued survival is obviously in doubt.
Toughness doesn't have to be measured by strength or stature. The pupfish of Death Valley show their toughness by surviving in one of the most extreme environments on Earth. They deserve our respect and protection, something we have not always provided. The Tecopa Pupfish (Cyprinodon nevadensis calidae) once lived in two hot springs east of Death Valley. Modifications of the springs in the 1960s to build bath houses destroyed their habitat, and they were gone by 1970. It was the first species to be taken off the endangered species list, not because it was doing better, but because it was extinct. Let's do better with the others.
Postscript: Since I originally posted this story on the pupfish, I've become aware of another species of pupfish in the region that was thought to be extinct, but which now is thriving on private property in Shoshone, east of Death Valley. Here is the very interesting story of their discovery. Biological and environmental details can be found here.
Welcome to one of the most remarkable places in the United States. It's a large island in the middle of the hottest and driest desert in the country. I freely admit that the unprepossessing photograph above is one of the least likely real estate ads ever, but it reveals the landscape of one of the most biologically unique spots in the continental United States, and this picture could have been a real estate ad in the early 1980s.
Crystal Spring at Ash Meadows
Ash Meadows National Wildlife Refuge is not in Death Valley proper, but instead lies about 30 miles east of Death Valley National Park. It is administered not by the National Park Service, but by the U.S. Fish and Wildlife Service. But it does enclose an outlier of Death Valley National Park, and it preserves critical habitat and nearly 30 endemic animal and plant species that were nearly extirpated in the 1970s and 1980s. The fact that it exists at all is entirely due to geology.
During the Pleistocene ice ages during the last two million years, the climate in this dry desert was often cooler and wetter. Rain and snow fell on the high mountain ranges to the north and east and soaked into the ground. Over the millennia the groundwater flowed slowly to the southwest, along river valleys and even through fissures right through mountain ranges. Bedrock ridges and gouge-filled fault lines forced the "fossil water" to the surface as a series of 30 or so seeps and springs. The amount of water flowing here is tremendous; some of the springs have flows measured in thousands of gallons per minute. For example, Crystal Springs in the pictures above and below has a flow of 2,800 gallons per minute. The presence of so much water in the desert makes Ash Meadows an island, but in this case it is an island of water in a landscape of dryness. It is one of the few oases left in the American desert, and has the highest concentration of endemic species in a small area anywhere on the continent.
Water in the desert attracts (and isolates) many kinds of plants and animals. Many are survivors, relics of wetter times who could not otherwise live in the desert. That would include the four native species of fish (a fifth is already extinct), and ten species of water snail (an eleventh is also extinct).
The proposed Calvada Lakes development from the 1980s
Water in the desert can also attract invasive species which can do great damage to the fragile ecosystem. Mosquito Fish, which are an important species in other settings, can upset the life balance in the pools and springs. So can abandoned aquarium fish. But the worst invasive species of all, Homo sapiens, nearly destroyed the entire complex.
It happened first when farmers began to manipulate the springs into irrigation systems. They piped the water flows and started pumping groundwater so intensely that the water table started to drop, threatening the species that lived in the ponds. Lawsuits ensued and one eventually reached the Supreme Court. In 1976, the court ruled that pumping had to be limited to the extent that water tables would not drop. The farming corporation sold the properties to a land developer, which led to an even greater threat to Ash Meadows.
The real estate development is in retrospect nearly unbelievable: more than 30,000 homes, along with shopping centers, casinos, theatres, and industrial parks. An instant city in the midst of barren desert. Even today, I can't imagine 50,000 people or more simply deciding to move out to the middle of nowhere. "But Las Vegas!" is an obvious response, but other desert town developments have faltered and disappeared when people realized how truly miserable the summer temperatures could be (and that's not to mention the winter winds and dust storms). Calvada Lakes would have been a disaster on so many levels.
Luckily, Congress stepped in and established the Ash Meadows National Wildlife Refuge in 1984, and most of the developer's lands were purchased by the Nature Conservancy in 1986. The lands were then re-sold to the federal government, and the refuge became a reality. Today, there is a marvelous new visitor center and three handicapped accessible boardwalks that explore some of the most interesting springs.
Devil's Hole Pupfish
The rain was still falling when we arrived at the refuge during our recent Bombogenesis trip to the Death Valley region. It had indeed been falling all night, so I should have known what was going to befall us when we tried to drive the gravel-clay road to Devil's Hole to see the most restricted vertebrate habitat on the planet. The vans very nearly got stuck in the slick mud, and we only made it out by getting out and pushing the van back onto semi-solid ground. We didn't make it, in other words. But we have in the past, and I'm providing a few pictures of the event.
The entire race of the Devil's Hole Pupfish lives in the shallow cavern opening on the side of a limestone hill. The water is constantly warm, almost 90 degrees, is oxygen poor, and the food supply for the fish is extremely limited. But somehow the fish have survived, and have diverged from their relatives who live in pools just a few miles away. They are thought to have been isolated for a minimum of 20,000 years, but some studies suggest as much as 60,000 years (an outlier study takes a different position, suggesting only a few centuries of isolation).
Access to the cave opening is for obvious reasons highly restricted. There is a caged platform from which the pool can be viewed from about 80 feet away. It's clearly hard to see the individual fish, but my camera has a great zoom lens. I'm not sure why they were there, but the white tiles in the pool allowed me to catch some video of the rarest fish in the world (below).
The cavern opening where the entire population of Devil's Hole Pupfish lives
There are islands in the desert. One might argue that islands are supposed to be surrounded by water, and water is in short supply in the driest corner of North America's Basin and Range province. But islands can take many forms, and in this region there are extremely high mountains and deep fault valleys that cross so many life zones that the "island" can be defined as an isolated ecosystem atop a high mountain. There are relict forests in the Mojave Desert of fir trees that survived the end of the ice ages in their cool mountain redoubts, for instance. On our way to Ash Meadows National Wildlife Refuge, we could see a mountain island rising out the Amargosa River plain. Eagle Mountain is an isolated fault block that rises above the blowing dust of the afternoon.
Desert surrounds Ash Meadows, an unlikely oasis in western Nevada
There are of course islands of civilization that persist in the desert, maintained by the importation of energy and supplies. These outposts actually make the exploration of this desert possible, one of the most isolated regions in the lower forty-eight states. In the end though, it is water that makes the islands. In this case an "island" of water surrounded by barren desert. It is the largest island of endemic species in the lower 48 states.
Endemic species are those that occur nowhere else on the planet. The boundaries of endemism are usually the shorelines of islands, because new species arise from isolation. Hawai'i is the absolute leader in endemic species in the United States, being one of the most remote islands on the planet. There are literally thousands of endemic plants and animals on the islands that are found nowhere else in the world. The Galapagos Islands are another famous example of numerous endemic species. There are lots of endemic species within the boundaries of the lower 48 states, but there are relatively few found in any specific area. There are simply too many pathways for species to spread out over a wide region.
One such island is the oasis of Ash Meadows in western Nevada. Within the 37 square miles of the National Wildlife Refuge are (or were) nearly three dozen endemic species of plants and animals, species found nowhere else on the planet. They exist in this one isolated location because of the geology, which has funneled the groundwater of a vast region into a series of three or four dozen springs that emit tens of thousands of gallons per minute. Water in the desert is life. Lots of water in one spot of the desert is almost miraculous, and that is the situation at Ash Meadows.
The creek that flows from Crystal Spring. An ADA accessible boardwalk provides access
The unique lifeforms found here include four living species of fish (along with one extinct species), eleven species of snails, three aquatic bugs, two species of bee, one extinct mammal (the Ash Meadows Montane Vole), and nine plant species.
"Ash" Meadows seems a particularly apt description of the region in winter
The desert that surrounds Ash Meadows is every bit as much a barrier to species travel as the open seas that surround Hawaii or the Galapagos. The meadows are only a few miles from Death Valley, the hottest place on the planet. So how did these water species come to be here in these springs and pools? Much of the explanation lies with the Pleistocene Ice Ages. A dozen or more times in the last 1.8 million years, the climate cooled and glaciers developed in the Sierra Nevada mountains off to the west. Meltwater from the glaciers filled the intermontane valleys of the Great Basin, forming a series of huge lakes and connecting rivers. These precious tendrils of water allowed fish and other aquatic species to invade the former deserts, but as each ice age stage ended, the dry conditions returned, and a few survivor species found safe harbor in isolated springs and pools like those found at Ash Meadows.
Devil's Hole, home of the extremely endangered Devil's Hole Pupfish. The pool in the cavern opening is their only home.
The refuge at Ash Meadows includes a single pool of water called Devil's Hole that contains the rarest fish species on the planet, the Devil's Hole Pupfish. The pool is an outlier of Death Valley National Park. Two other species of pupfish are found at Ash Meadows, the Ash Meadows Amargosa and the Warm Springs Pupfish. The Ash Meadows Speckled Dace is also found here. The Ash Meadows Killifish was driven to extinction in the 1950s as a result of spring alteration and agricultural development.
King's Spring can also be visited by an ADA accessible boardwalk.
It is remarkable that Ash Meadows ever came to be a protected ecosystem because water in the desert attracts another species, one capable of altering the landscape and erasing from existence the other species that have survived in isolation for tens of thousands of years. The water at Ash Meadows caught the attention of desert travelers more than a century ago, and the water was used to irrigate alfalfa fields and other crops. Many of the springs were put into piping systems and numerous invasive species arrived to compete with the native ones. It's hard to believe, but as recently as the 1980s, a proposal to build casinos, strip malls, and 30,000 houses almost became a reality.
If you have visited Ash Meadows in the past, you will find some major changes. A marvelous new visitor center opened only a few months ago. There was plenty of excellent information about the geology and biology of the refuge, but I was especially impressed with the paleontology exhibits. Entire walls are devoted to a creative diorama of the fossil species found in the region, including the ancient billion year old animals as well as the various waves of Homo sapiens throughout time.
Western Kingbird at Point of Rocks in Ash Meadows
Death Valley National Park is one of the greatest national parks in our country, and if you visit, you will find more than enough to keep you busy for many days. But if you find you have a day to spare, drive on over to Ash Meadows. Closed roads (flood damage) convinced us to pay a visit in February.
To wrap up, have a look at an Ash Meadows Amargosa Pupfish defending its territory at Longstreet Spring. These are fascinating creatures, and true survivors. In our next post we'll drive through a mountain range. Not over, but through...
Desert surrounds Ash Meadows, an unlikely oasis in western Nevada
The formations are described as two coiled rattlesnakes, although to the geologist, this is a trick of erosion. The barren limestone layers overlook one of the most unlikely ecosystems in the United States. It is the largest "island" of endemic species in the lower 48 states.
Crystal Springs at Ash Meadows. More than 15 feet deep, the springs put out 2,600 gallons of warm water each minute.
Endemic species are those that occur nowhere else on the planet. The boundaries of endemism are usually the shorelines of islands, because new species arise from isolation. Hawai'i is the absolute leader in endemic species in the United States, being one of the most remote islands on the planet. There are literally thousands of endemic plants and animals on the islands that are found nowhere else in the world. The Galapagos Islands are a famous example of numerous endemic species. There are lots of endemic species within the boundaries of the lower 48 states, but there are relatively few found in any specific area. There are simply too many pathways for species to spread out over a wide region.
"Meadow" is sometimes a strong term for the scrubby vegetation found in parts of the refuge. The alkalai soils are unique.
But there are "islands" in the lower 48. They are the opposite of Hawaii or Galapagos in the sense that these are islands of water in an ocean of dry barren desert. One such island is the oasis of Ash Meadows in western Nevada. Within the 37 square miles of the National Wildlife Refuge are (or were) nearly three dozen endemic species of plants and animals, species found nowhere else on the planet. They exist in this one isolated location because of the geology, which has funneled the groundwater of a vast region into a series of three or four dozen springs that emit tens of thousands of gallons per minute. Water in the desert is life. Lots of water in one spot of the desert is almost miraculous, and that is the situation at Ash Meadows.
The creek that flows from Crystal Spring. An ADA accessible boardwalk provides access
The unique lifeforms found here include four living species of fish (along with one extinct species), eleven species of snails, three aquatic bugs, two species of bee, one extinct mammal (the Ash Meadows Montane Vole), and nine plant species.
Longstreet Spring at Ash Meadows
The desert that surrounds Ash Meadows is every bit as much a barrier to species travel as the open seas that surround Hawaii or the Galapagos. The meadows are only a few miles from Death Valley, the hottest place on the planet. So how did these water species come to be here in these springs and pools? Much of the explanation lies with the Pleistocene Ice Ages. A dozen or more times in the last 1.8 million years, the climate cooled and glaciers developed in the Sierra Nevada mountains off to the west. Meltwater from the glaciers filled the intermontane valleys of the Great Basin, forming a series of huge lakes and connecting rivers. These precious tendrils of water allowed fish and other aquatic species to invade the former deserts, but as each ice age stage ended, the dry conditions returned, and a few survivor species found safe harbor in isolated springs and pools like those found at Ash Meadows.
Devil's Hole, home of the extremely endangered Devil's Hole Pupfish. The pool in the cavern opening is their only home.
The refuge at Ash Meadows includes a single pool of water called Devil's Hole that contains the rarest fish species on the planet, the Devil's Hole Pupfish. The pool is an outlier of Death Valley National Park. Two other species of pupfish are found at Ash Meadows, the Ash Meadows Amargosa and the Warm Springs Pupfish. The Ash Meadows Speckled Dace is also found here. The Ash Meadows Killifish was driven to extinction in the 1950s as a result of spring alteration and agricultural development.
King's Spring can also be visited by an ADA accessible boardwalk.
It is remarkable that Ash Meadows ever came to be a protected ecosystem because water in the desert attracts another species, one capable of altering the landscape and erasing from existence the other species that have survived in isolation for tens of thousands of years. The water at Ash Meadows caught the attention of desert travelers more than a century ago, and the water was used to irrigate alfalfa fields and other crops. Many of the springs were put into piping systems and numerous invasive species arrived to compete with the native ones. It's hard to believe, but as recently as the 1980s, a proposal to build casinos, strip malls, and 30,000 houses almost became reality.
If you have visited Ash Meadows in the past, you will find some major changes. A marvelous new visitor center opened only a few months ago. There was plenty of excellent information about the geology and biology of the refuge, but I was especially impressed with the paleontology exhibits. We spent an entire day visiting and could have spent more.
Western Kingbird at Point of Rocks in Ash Meadows
Death Valley National Park is one of the greatest national parks in our country, and if you visit, you will find more than enough to keep you busy for many days. But if you find you have a day to spare, drive on over to Ash Meadows. It's only forty or so miles away from Furnace Creek.
To wrap up, have a look at an Ash Meadows Amargosa Pupfish defending its territory at Longstreet Spring. These are fascinating creatures, and true survivors.
There is a lonely nondescript mountain of limestone in the barren desert east of Death Valley National Park. There is a hole at the base of the slope, the entrance to a cavern. Lurking within are prisoners, creatures that have been trapped in the cave for perhaps 20,000 years or more. They are mutants, no longer the same as their cousins who live freely just a few miles away. They are alone in the world.
That sounds kind of dramatic I suppose, but all of it is technically true. The story becomes a bit stranger when one realizes that the trapped creatures are fish. In one of the driest climates in North America.
During the Ice Ages between 1.8 million and 10,000 years ago, glaciers in the Sierra Nevada were constantly melting in their lower reaches, and some of the resulting streams and rivers drained into the desert regions to the east. The faulted valleys would fill with water and spill over into the next so that at times an entire network of lakes and rivers existed. At some point a connection was made with the Colorado River system and fish worked their way into the widespread habitats. Dozens of species thrived in the freshwater lakes.
But then conditions began to change. The climate grew warmer and the glaciers mostly melted away. One by one the lakes dried up as the rivers that once fed them turned to trickles and then disappeared. Most of the fish died out, but here and there springs or remnant lakes allowed some species to survive. The most isolated species of them all lives in this one hole, the Devil's Hole. The Devil's Hole Pupfish (Cyprinodon diabolis) is in all likelihood the rarest fish in the world. There have never been more than five or six hundred of them, and their population has reached lows of only three dozen at times. They are living at the extremes, as the water is at a constant temperature of 93 degrees. Only a few other species of pupfish can survive those kinds of temperatures (you can read about some of the other species here: http://geotripper.blogspot.com/2015/02/you-think-some-fish-you-caught-was.html ).
Their rarity explains the monitoring equipment and fencing that surrounds the cavern opening. The pool is visible from in side a caged tunnel, but the individual fish are a bit difficult to see. They're only an inch long, and the viewing platform is around a hundred feet away. I saw nothing on my previous visit five or six years ago, but this time I did.
The efforts to protect the fish almost became their undoing when a 2004 flash flood dumped the monitoring platform and other debris into their pool. Something like a third of the population was lost. The platform was gone and there was a limited amount of equipment. And, there were three squares of what looked like white astroturf in the water. I don't know their purpose, but one idea is that they may protect eggs. Or maybe someone was making it possible to see the fish from so far away.
The fish feed from the algae covered bench on the near side of the pool. That bench was the crux of a Supreme Court decision in 1976 that prevented the extinction of the fish. At the time developers were digging deep industrial wells to promote the agricultural development of the adjacent valley, and the water level at Devils Hole began to drop. The court put a stop to the drilling, and the surrounding region became the Ash Meadows National Wildlife Refuge. It turns out to have been an astonishingly lucky turn of events, as the refuge has the largest concentration of endemic species in the continental United States (Hawaii is the only state with more endemic species).
In any case, I got to see the Devils Hole Pupfish, the rarest fish on the planet, for the first time ever. Thank goodness for a good zoom lens (bring binoculars or a good camera if you ever visit). The squares are only a foot or so across, but one could make out the shapes of the fish as they swam over the light colored material.
So here is the cropped and enlarged version of the image above, which doesn't show much, but remember I was more than 100 feet away.
If it helps, here (from the interpretive sign at the site) is what they really look like:
I even managed to get a very short video of the fish (all of 8 seconds or so).
It's not every day that one can see the rarest of anything. If you ever find yourself in the Death Valley region, don't pass up the opportunity to see these fascinating creatures. They could be extinct any day despite our incredible efforts.
What kinds of fish are tough? Some Marlin that you spent a couple of hours trying to reel in one time in Mexico? A nice two pound Rainbow Trout that fought hard against your fishing skills in a mountain lake in the Sierra? Some Small-mouth Bass in a reservoir somewhere? I doubt any of them can stack up to this little fish. They were out and about last week during our field trip in numbers I haven't seen in some time.
It's little, hardly exceeding two inches in length. It's certainly not big enough to take a hook. It doesn't have a mouthful of teeth, and it's not a predator (unless you are a diatom or a clump of algae). So how is this a tough fish?
Consider this: it lives in water that can sometimes exceed the saltiness of seawater. By three times. I don't think there is another fish in the world that can do that. And...it can survive in water where the temperature exceeds 100 degrees. Again, I don't think there is another fish in the world that can do that. And one more: the environment in which these fish live can reaching freezing on occasion. No fish that I am aware of can survive such extremes.
But these little fish can.
On top of everything else about this species is the place where it lives,
the last place one would even think of looking for fish: Death Valley in
eastern California. The hottest place in the world, and the driest
place in North America.
Meet the Death Valley Pupfish (Cyprinodon salinus salinus), sometimes known as the Salt Creek Pupfish. It is just one of nine or so species and subspecies of fish that survive in the Death Valley region.
Once you realize that fish are living in Death Valley, certain questions are bound to arise. How can there be water enough for them to survive? How did they get there? And how did there come to be so many species and subspecies ?
The first question is perhaps the easiest to answer. It is true that rain almost never falls in Death Valley, with an average year seeing no more than 1.5-2 inches of precipitation. But Death Valley is the lowest ground in North America, and groundwater flows towards the valley, in some cases from a hundred miles away. Springs and pools form when faults or rock barriers force the water to the surface. These water sources don't depend on the rare rainstorm. It's thought that the water flowing from springs at Furnace Creek or Scotty's Castle has been underground for more than 10,000 years. These stable springs and pools have provided a secure source of water since the end of the last ice age around 12,000 years ago.
But how did the fish get there in the first place? We can say that the fish did not arrive under current climate conditions. River connections between fault basins could only occur during the ice ages when glaciers covered about 30% of the Sierra Nevada. Glacial meltwater drained into the Owens Valley and spilled over into other desert valleys, filling them, and ultimately filling even Death Valley with a hundred mile long freshwater lake. At some point, a connection was made with the Colorado River, and numerous species of fish invaded the ecosystem. But then the ice ages ended.
The vast lakes began to dry up, and the fish were forced to adapt or die out. A number of trout species survived in the cool waters of the Carson, Walker and Truckee River drainages, but in Death Valley, it was only the Cyprinodon species. The one species was forced to survive in different environments, water that might be fresh, salty, hotter, or cooler. The single species diverged into many, much as the finches of the Galapagos Islands did.
During the spring, the Salt Creek Pupfish expand rapidly into the growing flow downstream. Hundreds of fish become thousands, then a million or more. Most of them are doomed when the extreme summer heat sets in and Salt Creek mostly dries up. A few find refuge in the pools and springs at the head of the shallow canyon (a canyon that exists on the floor of Death Valley because of faulting).
Other species of pupfish are more severely limited. The Devil's Hole Pupfish is restricted to a single cavern opening only a few tens of feet across. It is said to be the most endangered vertebrate species in America and maybe the world. There have rarely been more than 300, and at times the population has dipped to barely two dozen. Their continued survival is obviously in doubt.
Toughness doesn't have to be measured by strength or stature. The pupfish of Death Valley show their toughness by surviving in one of the most extreme environments on Earth. They deserve our respect and protection, something we have not always provided. The Tecopa Pupfish (Cyprinodon nevadensis calidae) once lived in two hot springs east of Death Valley. Modifications of the springs in the 1960s to build bath houses destroyed their habitat, and they were gone by 1970. It was the first species to be taken off the endangered species list, not because it was doing better, but because it was extinct. Let's do better with the others.
