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| Canadian photo circa 1875 |
On
July 20, 1875, the second year of a prolonged drought, farmers in eastern Colorado looked up to see an odd,
shimmering cloud boiling towards them.
It was the head of a swarm of
Rocky Mountain Locust that would eventually grow to be 1,800 miles long and
110 miles wide and stretch from southern Canada
to north Texas covering an area
larger than California. The swarm contained an estimated 3.5 trillion
insects and may have been the largest concentration of individuals of any
species in world history.
The
locusts, a species of grasshopper,
should not be confused with the Mormon
Crickets that had devastated Utah
decades earlier.
The
locusts were insatiable and stripped fields in minutes. They ate anything—leaves and bark off of
trees, fence posts, tool handles, laundry left hanging. They even devoured the harnesses off of mules
in the field. There were reports of men
having the clothing eaten off of their backs.
In some places the locusts were up to a foot deep on the ground.
Laura Ingles Wilder in her book On
the Banks of Plum Creek described the swarm descending on the family’s Minnesota farm:
The cloud was
hailing grasshoppers. The cloud was grasshoppers. Their bodies hid the sun and
made darkness. . . . The rasping whirring of their wings filled the whole air
and they hit the ground and the house with the noise of a hailstorm. . . .
Laura had to step on grasshoppers and they smashed squirming and slimy under
her feet.
Except
along a few river valleys, wide-spread
farming was relatively new to the high plateau Great Plains. Only 15 years
earlier at the end of the Civil War
it was marked as the Great American
Desert on most maps and was the home of vast buffalo herds and the Native
American tribes that hunted them.
But the coming of railroads,
intense hunting of the buffalo herds, and the Homestead Act had rapidly opened the area to pioneer dry land farming.
The
locusts had traditionally had a roughly seven year cycle between major swarms
and the swarms grew in size when conditions were dry and the soil dusty. Conditions
were perfect in 1875 and the new crops provided new food sources. Smaller, localized swarms broke out the next
two years.
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| Contemporary Ma[ shows the broad range of the Locust Swarm. |
Then
the drought broke and the area entered an extended period—virtually up to the Dust Bowl era—of unusually wet
conditions. Year to year farmers waited
with dread for the expected reoccurrence of the swarms. But they never came. Instead the once ubiquitous creatures
evidently became extinct. The two last
living specimens ever collected were found in southern Canada in 1902.
Extensive
tests of DNA in grasshopper
specimens collected over the region have never turned up a match and scientists
have discounted a theory that more common grasshoppers could somehow mutate
into swarming locusts. As it is,
localized grasshopper infestations do millions of dollars in crop damage in dry
years, but nothing on the scale of the locusts.
The
exact cause of the sudden disappearance may never be known. A few entomologists
suggest some kind of mite or other parasite. Most, however, believe that the very success
of the final main swarm and the persistence of farming may have doomed the
species.
The
insects typically deposited their eggs in the sandy soil of river valleys. The huge numbers in this swarm deposited
equally huge numbers of eggs. But the
river valleys—and their critical access to vital water—were most attractive to
settlers who noted the presence of millions of white “grubs” when plowing the ground in subsequent years. The farms that were the victims of the swarm
thus disrupted the natural breeding cycle and the species could not adapt.
The
1875 swarm may also have been nearly fatal to the dwindling herds of already
over-hunted buffalo. The insects ate the
prairie grass as well as crops. By 1880
they were nearly gone and the tribes that depended on them in a virtual state
of starvation, hastening their agreement to be confined to reservations and go on government beef rations.
The
disappearance of the locust threat, on the other hand, plus the years of
unusually high rain fall, led to an explosion of dry land farming and
population on the Great Plains. After
the collapse of the Dust Bowl, remaining farmers turned to irrigation drawing on the vast Colorado
Aquifer. But that source has been
dangerously drained and scholars believe wide-spread farming in much of the
region will become unsustainable. Some
have even suggested abandoning agriculture in the area entirely and allowing
the land to go back to its original prairie.
Nature seeking a balance.
