The mystery of 53 dead caribou
in the Alaska Range
By Ned Rozell
May 24, 2007
Thirty-five years ago, an Army helicopter pilot flying over an
Alaska tundra plateau saw a group of caribou. Thinking something
looked weird, he circled for a closer look. The animals, dozens
of them, were dead.
The pilot reported what he saw to the Alaska Department of Fish
and Game. The caribou, 48 adults and five calves, were lying
in a group. The way their carcasses rested showed no signs that
the animals had been running from a predator.
As word spread of the 53 dead caribou, people speculated what
might have killed them: Nerve gas, toxic waste or some other
dark secret from the Army post nearby, flying saucers, maybe
a lightning strike?
Photo by Aaron Collins,
courtesy the U.S. Fish & Wildlife Service:
According to the Alaska Department of Fish and Game, Alaska caribou
are distributed into 32 separate herds. Pictured, are several
members of a heard moving through the Togiak National Wildlife
Refuge, a 4.7 million acre wilderness area, located in Southwest
The Alaska Department of Fish and Game sent wildlife disease
specialist Ken Neiland to the site, about 33 miles southwest
of Delta Junction. Glenn Shaw, a young atmospheric scientist
from the Geophysical Institute at the University of Alaska Fairbanks,
went with him. Shaw had studied lightning before.
From the air, the scientists saw a clue to the animals' death,
a giant "Lichtenberg figure" etched into the ground
near the carcasses. A Lichtenberg figure is a pattern of cracks
extending from a central bullseye.
Upon landing, Shaw and Neiland (now deceased) saw signs of bears
and eagles that had scavenged the carcasses to the point where
Neiland could obtain few samples of internal organs for necropsy.
After seeing nine individual spokes that had ripped outward along
the tundra in tortuous paths, Shaw knew what killed the caribou.
"From what I saw out there and from what I've seen in the
past, I'd say the probability that those caribou were done in
by lightning is 99 percent," Shaw told Fairbanks Daily News-Miner
reporter Ed Martley.
Shaw, still a professor of physics at the Geophysical Institute,
said that four-legged animals are more prone to electrocution
by lighting than human beings because the span between a caribou's
four legs allows a greater electrical charge to build between
them. Also, he said the ground was probably wet, which led to
greater conduction during the lightning strike. He concluded
in a paper that the height of the caribou probably had little
to do with attracting the lightning strike, and that the animals
were just in the wrong place at the wrong time. He ended his
paper with the rough estimate that a similar lightning strike
will kill a group of caribou once every 25 years in Alaska.
Veteran Alaska biologists remember the June 1972 event and say
that nothing like it has happened since.
"I can't think of any," said Ken Whitten, a longtime
caribou biologist for the Alaska Department of Fish and Game.
"But it certainly happens with elk and bighorn sheep in
"I think it is quite rare," said Jim Davis, a biologist
who retired from the Department of Fish and Game in 1990. "I
think avalanches and drownings are infinitely more frequent than
(caribou deaths by) lightning strikes."
Biologist Steve Arthur has studied northern caribou for years
and has seen evidence of caribou triggering avalanches.
"Flying around in the Brooks Range in wintertime, we've
seen tracks running into avalanche chutes and not coming out
the other side," he said.
Davis remembered a 1984 incident in Quebec where about 10,000
caribou drowned while crossing the Calcaire Falls of the Caniapiscau
River. That massive die-off sparked debate about the role of
a dam and reservoir built upstream.
Alaska probably has not seen another incident like the lightning
strike of 1972, but there's a lot of country out there, Whitten
"We just don't have the density of people in Alaska to see
all these things," he said.
In his 1973 paper, Shaw concluded the same thing about the bigness
of Alaska: "No doubt mass mortality of gregarious species
of wildlife by lightning stroke occur more often than is indicated
by the paucity of records in the literature."
This column is provided
as a public service by the Geophysical
Institute, University of Alaska Fairbanks, in cooperation
with the UAF research community.
Ned Rozell [email@example.com]
is a science writer at the institute.
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