Walrus Forensic Investigation
How can a dead, headless walrus expose the intent of its killer?
That puzzle stumped the three scientists -- Goddard, Espinoza, and Stroud -- as they prepared for the walrus investigation. Because Native Alaskans hunt walrus in late spring and early summer, the scientists would trek to Alaska at the end of July, after the season's final storms, to examine that year's carcasses. But to make their trip worthwhile, they needed a way to answer the basic question: were the headless walrus killed solely for their tusks?
As in any case, they started with what they knew. Native hunters shot their prey at sea, either while the walrus rested on floes or swam in open water (a practice called pelagic hunting). Unless bad weather or other hazards prevented it, they butchered the animals on the ice and, if their intentions were for subsistence, took as much of the hide, meat, organs, blubber, and ivory as they could use.
Killing for subsistence was legal while killing for commercial purposes was not. Consequently, the scientists would focus primarily on why the animals died and use any information they could gather on cause or manner of death or on who did it, to point to the hunter's intent. They needed to establish whether walrus were being killed wastefully by Native hunters.
They would have little evidence to go on. Because the killings would have occurred somewhere at sea days or weeks earlier, before the animals washed up on shore, they would have no witnesses and no crime scene. Even if they had, wind and weather would likely have corrupted the physical or trace evidence. They would have to infer intent from the major piece of evidence they did have: the decomposing carcasses.
But what could a dead walrus tell them?
If the victim had been human, the scientists would have known what to expect. Regular crime labs use tried-and-true technology to produce results in which they know the chance for error. DNA testing in rape cases identifies suspects. Bullet trajectories and blood spatters reveal the position of the killer. But the wildlife crime lab was not so lucky. Nobody had worked with a walrus carcass before to ascertain whether it had been legally killed. They would have to adapt existing techniques and develop new ones to coax the walrus corpse into divulging everything it could.
During the winter and spring of 1990, in between their other duties, the scientists contemplated what data would signal wasteful kills versus subsistence kills. All three came at the problem from distinct professional viewpoints.
They began with Goddard's. Goddard's approach was determined by his background as both a cop and a criminalist. After graduating from the University of California-Riverside in 1968 with a bachelor of science in biochemistry, Goddard worked at the Riverside County Sheriff's Department as a deputy sheriff/criminalist. Ultimately he chose to focus exclusively on forensics. A charismatic, garrulous man with prematurely white hair and a coy white mustache, he went on to work at other crime labs before becoming the first director of the FWS crime lab in 1979. The wry twinkle in his eye and his humorous asides suggested that in his years of crime scene investigation he'd seen it all and was prepared for anything.
Criminalistics, Goddard's specialty, is a term often used interchangeably with forensic science. It refers to the examination, identification, and interpretation of physical evidence from a crime to reconstruct events and link a suspect to the victim. As Paul Kirk, the "father of criminalistics," noted, trace evidence "cannot perjure itself" or "be wholly absent." Criminalistics is based on the theory that every contact leaves some residue in the form of evidence, such as blood, tissue, fingerprints, bullets, tire tracks, shoe impressions, or hair and clothing fibers.
The most obvious form of physical evidence they might reasonably uncover in the walrus carcasses would be bullets. Bullets could prove death by gunshot, reveal the type of rifle used, or even identify the specific weapon used in the hunt. That information might rule out Russians as responsible for the killings, and thus point to Native hunters. That would be a worthwhile discovery. However, their utility for indicating wastefulness was poor because guns were used by all hunters whether for subsistence or commercial purposes. The bullets wouldn't help them distinguish between the two. For that, they needed a better line of attack.
While Ed Espinoza was a criminalist like Goddard, he was also a skilled forensic chemist. He was a patient man, in his late thirties, with a crisp Chilean accent who spoke and acted in a deliberate way. He held a bachelor of science degree in medical technology from Loma Linda University in California, both a master's and doctorate in forensic science from the University of California-Berkeley, and had worked as an assistant professor of forensic sciences and as a private practice forensic consultant specializing in homicide cases before joining the lab in 1989.
Forensic chemists use highly specialized techniques to analyze the chemical composition of organic and inorganic substances such as poisons, fire accelerants, blood, tissue, and bones to determine how an organism died. They also study decomposition and weathering to infer what happened after death.
To prove wastefulness, the scientists needed to know what happened to the walrus after they died. If the walrus had been legally killed for subsistence, the carcass would lack not only the head but also other parts such as meat, hide, and flippers. If someone had severed the heads of already dead animals washed up on the beaches, it would indicate the also legal practice of beachcombing. If, however, the heads had been cut off before being beachcast, it could be a sign of illicit headhunting.
Espinoza hypothesized that diatoms, microscopic (between 20 to 200 microns in diameter or length) single-celled photosynthesizing algae that live in both fresh and salt water, imbedded in the necks of the carcasses might tell them when the heads were removed -- either before the dead animals entered the water or after they had washed up on the beach. Because living diatoms have specific salinity, temperature, and other environmental tolerances, species vary by location. Scientists then use this information to match the composition of diatoms in the victim's body to those in a particular water source. In human forensics, they are used in two main ways: to identify a specific body of water, like a lake, and to determine whether a victim died before or after entering water.
Scientists analyze diatoms in bodies recovered in water to tell if the body was alive or dead when it entered the water. The theory behind this test is that if a person drowns, the diatoms in the water will reach the lungs and, if the heart is still beating, enter the bloodstream and circulate around the body, lodging in internal organs -- kidneys, brain, bone marrow -- before death. If the body was dead when it entered the water, diatoms would still reach the lungs through passive means, but they would be absent in the more distant organs because no circulatory transfer could occur.
The walrus situation was analogous. Although knowing if the animals were dead before entering the water was immaterial for determining headhunting, knowing if an otherwise intact carcass had its head removed before it entered the water would be a valuable indicator of wasteful hunting. If the head had been removed from an otherwise intact carcass on an ice floe before the body entered the water, there would be diatoms on the exposed neck area. If the head of an otherwise intact carcass had been removed after the body washed up on shore, there would be no diatoms present.
Espinoza did allow that waves splashing on the carcasses might leave diatoms, although perhaps not as many. For this method to be useful, the scientists would have to know how diatom concentrations and composition varied between the two scenarios. Yet that detailed level of diatom data simply wasn't available. They would need more research -- and a lot of it. To acquire the information, the lab would have to extract diatoms from different water depths across the walrus's entire marine environment, purify them, and then analyze them. That would be a complex, expensive, and time-consuming procedure. They needed a better option.
The third member of the team, Dick Stroud, approached the determination of wasteful hunting from his medical examiner's perspective. Medical examiners -- medical doctors with specialized training in forensic pathology -- use their knowledge of disease and body processes to determine what caused a person's death. They perform autopsies and analyze organs, tissues, and bodily fluids for indications of the circumstances of sudden fatalities. Stroud, as a veterinary pathologist, was no different, except his subjects were animals.
Since his childhood in Texas, Stroud had always been interested in wildlife. An avid hunter and fisherman, he began his career in the early 1960s as a wildlife biologist collecting data from the fur seal harvest on Alaska's Pribilof Islands, and then later participated in a pelagic research program where fur seals and other marine mammals were collected at sea and the stomach contents analyzed for species of prey. The dead animals never bothered him. To the contrary, he was used to working with animal carcasses in various stages of decomposition. To Stroud, the wonders of the functional body fascinated him and spurred his desire to study how the structure of an animal's organs and body systems changed due to disease, parasites, or injury.
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