Fuzz, p.23
Fuzz, page 23
What happened, in the end, to the rabbits? Through persistence, resistance, and multiplication, they’re doing just fine. They survived the stoats and cats and rabbiters, and even the rabbit hemorrhagic virus smuggled in from Australia. Shaun says he’s seen more than ever this year. With plenty of rabbits to eat, the stoats are thriving, too. “Stoats are through the roof,” he says over his shoulder, from the driver’s seat of the van that is taking us away from this beautiful and heartbreaking place.
Samantha Brown is a young biologist with freckles across her nose and an ear-pleasing Kiwi accent and extensive knowledge of how to kill quickly. Sam works with Bruce Warburton at Land-care Research, one of New Zealand’s Crown Research Institutes. Their branch, on the outskirts of Christchurch, focuses on biodiversity and sustainability. That means lots of appealing job prospects for conservation majors. Though sometimes less so when they hear about the trap testing.
While we wait for Warburton to arrive, Sam cues up a video shot at the test facility, a few miles down the road. No tests are scheduled this week, which is, for me, less a disappointment than a relief. I appreciate and respect the good and emotionally wringing work the team does, but I wasn’t sure I wanted to watch it live. There are things I too don’t like to stick my head inside.
The setup is simple. A video camera on a tripod faces an observation pen. A person waits in the dark with a stopwatch and feelings it is hard for me to guess at. Sam points to a readout below the video frame. “You can see the time elapsing down here.” Once the trap is sprung, the observer clicks the stopwatch. Humaneness, in the context of a lethal trap, is a function of speed: speed of death, yes, but more critically, speed to unconsciousness—to feeling and knowing nothing.
“This is a test of a Northland Regional Council cat trap,” says Sam. The SA2 Kat trap is used not only on feral cats but also brushtail possums. The possums, native to Australia, were released in New Zealand in the nineteenth century to establish a fur trade. They have thrived in their new home and multiplied and spread, feeding on and destroying vast numbers of trees that support native birds. On top of the estimated 21,000 tons of leaves and shoots they consume nightly, the brushtail possum also enjoys an egg.
On the screen, the time is displayed in tenths of seconds, increments that speed by unreadably fast, unless of course it’s you in the trap. Sam and I sit silently through a half minute of don’t-go-in-there, and then the terrible in-there. A colleague of Sam’s rushes into the frame. Some part of me hopes he’s been compelled to set the animal free. Sam narrates. “Here Grant is trying to look ’round the side of the head and touch the side of the eye.” He’s checking for the palpebral* blink reflex. When the reflex disappears, the animal is unconscious and the stopwatch is stopped.
The trap being tested in the video employs a metal bar that, when sprung, clamps down on the neck. While it’s possible to kill a mouse or even a rat by snapping the neck in this manner, a larger animal in a trap like this one is killed by strangulation: the bar clamping shut the carotid arteries, depriving the brain of blood and thus oxygen. Suffocation plays a supporting role, as the bar may also shut the windpipe. Suffocation achieves the same end point as strangulation, but it takes longer, because it is cutting off air intake instead of blood flow. Thus the blood keeps circulating, and it takes a while for the oxygen already in the blood to be depleted. With a well-designed trap of this variety, oblivion arrives in 40 to 50 seconds. (Most film directors, though not Tarantino, accelerate strangulation to five or ten seconds, because, really, who wants to see more than that?)
A faster, kinder death could be delivered through a blow to the head. As a humane means of ending life, few things rival a bullet to the brain; thus “properly placed gunshot” is included as an acceptable mode of euthanasia in the guidelines issued by the American Veterinary Medical Association (AVMA).† The world’s first humane kill trap featured, in fact, a gun to the head. U.S. Patent No. 269,766, granted to James Alexander Williams of Fredonia, Texas, in 1882, featured a revolver set upright in a frame. In the illustration accompanying the patent, the barrel is pointed at some variety of rodent emerging from a burrow. Varmint steps on rod, rod pushes trigger. You don’t get the sense, in reading the patent details, that Mr. Williams cared much about safety or humaneness or even rodent control: “This invention may also be used in connection with a door or window, so as to kill any person or thing opening the door or window to which it is attached.”
So why are the makers of the SA2 Kat trap not trying to hit the skull? Because a humane head strike needs to be carefully placed. Carotid occlusion affords more leeway with body size and position. Also, Sam is saying, for the bar to hit with force sufficient to deliver a lethal, humane blow, one starts running into (human) safety issues. It would take some good strength to pull back the bar to set the thing, and if it got away and snapped shut on someone’s fingers, bones would break.
Humane traps for stoats are among those designed to impact the head. This is because these animals have unusually strong, muscular necks, and the thick muscles protect the arteries. Also, the strength those muscles supply can enable the stoat to pull free.
Sam clicks a link for a video of a test of a stoat trap called a “modified Victor.” This is the classic wooden Victor brand snap trap for rats, upgraded (by Warburton) for humanely killing stoats. A molded plastic hood, or shroud, is screwed in place over the bait to guide the head in from the proper direction and to the proper depth. The bar strikes at the latitude of the ears, and unconsciousness, Sam is saying, is almost instant.
“You can see it’s started to go limp already.” My brain offers a more benign interpretation of what it’s taking in. Look, it’s one of those fur boas ladies wore to be classy in the nineteen forties.
When I was twenty-two, I lived in a mouse-infested apartment building. The Mouse Death Count—lettered in German Gothic and stuck on the refrigerator by my graphic designer roommate—was up to thirty-two hash marks by the time I moved out. The landlord didn’t allow cats, so we bought traps, the classic, cheap wooden Victor snap trap, the setting and disposal of which were my chore. I set them without much thought, assuming that they kill instantly because they hit the head or the neck. I was always taken aback by a mouse struck elsewhere: the one who came in from the side and was pinned by the shoulder. Another that changed its mind and got pinched by the snout while backing away.
According to University of Guelph bioscientist Georgia Mason’s thorough, unblinking comparison of the humaneness of various rodent control methods, this sort of thing happens 4 percent of the time with a Victor snap trap. That’s actually quite good, certainly compared to a competitor that, according to Mason, caught mice by the legs or tail 57 percent of the time. Mason studies behavioral biology at the university’s Campbell Centre for the Study of Animal Welfare, and her comparison study ran in the journal Animal Welfare. She is Canada’s Bruce Warburton. She’s outstanding.
These days the Victor company sells its own version of Warburton’s “modified Victor,” a snap trap called the Quick-Kill.‡ I commend them for this, but am disappointed to see that they continue to sell glue traps in their 2019 product catalog.§ On top of the protracted torment of being glued in place, the animal may, Mason writes, rip off pieces of skin or gnaw through its limbs trying to escape. A professional pest control person should be checking the traps daily and humanely killing any rodent that’s been caught, but Victor and others sell glue traps online to anyone, and what homeowner is going to tackle that? So millions of mice and rats are left, adhered, to die slowly of dehydration. Luckier, Mason says, are the ones who get their snout stuck to the tray in the initial struggle and suffocate.
Glue traps are illegal in New Zealand and parts of Europe. I emailed the Victor product manager, asking whether the company had plans to stop selling glue traps. You won’t believe this, but she didn’t answer.
Sam’s office door swings open. It’s Warburton with a box of traps. A couple decades of his career in there. It clanks as he sets it down to shake my hand. Warburton has a genial, wry manner. He doesn’t work at making everyone like him, but I imagine everyone does. He’s an interesting hybrid: animal ethicist and hunter. I ask him how he got involved in the business of humaneness. It began, he says, when New Zealand’s Society for the Prevention of Cruelty to Animals took an interest in a new, humane possum trap that they hoped could replace a particularly unkind leghold trap—key words: serrated jaws. (Possums are still commercially trapped for their fur, which is spun into wool.)¶ “They took it to our minister of forestry, and he said, ‘Well, how good is this trap?’ and he came to us.” Us meaning Landcare.
I guess I was less interested in the how than the why. I rephrase my question.
“I mean, they are pests,” Warburton says, “but they’re sentient animals.# They have the capacity to suffer. We have a duty of care to think about it, to minimize their suffering. That’s just been my philosophy.”
The traps in Warburton’s box are mostly mechanical: trigger and thwack. Where’s the newfangled stuff I’ve been reading about? Before I arrived in New Zealand I spoke to a Predator Free 2050 researcher about a humane carbon dioxide trap under development for stoats and rats. The animal enters a tunnel and crosses an infrared beam, triggering doors at either end to close and carbon dioxide to be expelled.
At the right concentration and flow rate, carbon dioxide is believed to kill humanely. The gas is one of the AVMA’s acceptable means of euthanasia. When a wildlife control operator live-traps Canada geese, say, or a raccoon in someone’s attic, a CO2 chamber may be the next stop. The operator may not mention this to the homeowner, and the homeowner may not ask, preferring to believe that the word humane on the operator’s website means that the animal will be driven to some sunny woodland and set free. (Which may be less humane than the gas. See “The Fuzzy Trespasser: Resources for Homeowners,” page 297, for advice on this.)
The humaneness of carbon dioxide was a subject of renewed debate at the 2018 AVMA Humane Endings Symposium. This is an animal euthanasia research conference held regularly near Chicago in November. Appealing! Here is the dilemma. It is elevated carbon dioxide levels in the blood, not low oxygen levels, that cause an organism to breathe harder. To avoid causing breathlessness and panic, you want the end to come quickly. But when the concentration and flow rate are high enough to achieve that, the CO2 may start to form an acid on contact with mucous membranes, and the animal may experience burning and choking sensations. Getting it right is tricky.
Another newcomer to the humane endings arena is the electronic trap. These are box traps with double-decker electrified floor plates. When a visitor steps inside, the top plate tilts into contact with the lower one, completing the circuit and introducing the current into the visitor. Warburton tested one such device designed for possums. It was, he says, a mixed success in terms of animal welfare. “It works okay when the electrode plates are clean, but once they got a bit dirty, it cooked the wrists of the animal. So that wasn’t very good at all.” Warburton shares what seems to me to be a national distaste for euphemism and double-talk. His words are not offensive, just direct. Delivered flat, and at low volume. I won’t be needing any exclamation points for the next few pages.
Georgia Mason weighed in on a commercially available version called the Rat Zapper. Two thousand volts for two minutes. (As this gets underway, the homeowner receives a text: “RODENT CAUGHT.” ROMANTIC DINNER RUINED.) Electrocution kills by disrupting the normal movements of the heart and diaphragm muscles. It’s a death by ventricular fibrillation and respiratory distress, both of which starve the brain of oxygen. So painful are the muscle constrictions thought to be that humane livestock electrocution requires the shock to the body be preceded—or at least accompanied—by passing a current through the brain to induce unconsciousness. Whether these traps also do this is not known.
Mason ranked a well-designed electronic trap alongside a good snap trap as most humane of all the lethal options for rodents, largely because both kill quickly. The cutoff in New Zealand for an allowably humane kill trap is three minutes to irreversible unconsciousness. Having watched test videos of two traps that came in under a minute, three minutes strikes me as an eternity. Warburton overhears me saying this to Sam.
“Three minutes is not too bad,” he says, putting traps back in the box. “The poisons are the tough ones.” Here is the ugly reality of keeping stoats and possums and rats from causing extinctions. Predator Free 2050 relies more on aerial drops of poison bait than they do on the happy trapping of motivated citizens. Given the numbers and remoteness of some of the creatures that prey on native birds, traps are not going to get them all. And if you don’t get them all, they will quickly bounce back—the rats especially.
New Zealand’s DOC has been looking into better poisons: poisons that kill humanely, poisons that kill the targeted invasive species and no other creatures, poisons that don’t build up on the land and in the animals that live off the land. And Landcare dutifully tests them. “It’s quite hard on the staff,” Warburton says. Because it’s hard on the testees. Because now you’re talking about hours or days, not minutes or seconds.
The tests are run near the facility where the traps are tested, a short drive from Landcare’s offices. Warburton is holding car keys. “You wanted to see it?”
If you do an image search for “L pill,” Google will present you with many close-up photographs of low-dose aspirin tablets marked with an L. This made me laugh out loud, because the L pill I was interested in was the kind issued to World War II operatives facing torture and possible spillage of top-secret beans. The L standing for lethal. L-pills, as the name was styled, contained potassium cyanide. The OSS, forerunner of the CIA, chose cyanide because it’s a fast, easily concealed way to end a person’s life.
In her consideration of the various rodent poisons, Georgia Mason ranks cyanide as the most humane. It suppresses central nervous system activity, and it interferes with the blood’s ability to ferry oxygen to the cells, causing a sort of chemical asphyxiation. Mason cites two New Zealand studies of ingested cyanide, one indicating that possums lost consciousness after a minute to a minute and a half, the other finding that it took around five minutes. In the span of time before oblivion, there were muscle spasms, which would be painful, and some convulsions. Because the convulsions occurred after the EEG indicated a loss of consciousness, the animal wouldn’t have been aware of them.
However, an onlooker would. Appearances matter. When states execute prisoners via a “cocktail” of drugs, they usually opt to include something to paralyze the muscles. Are they wishing to paralyze the breathing muscles or are they more concerned with the clenching, grimacing, spasming, convulsing muscles? I ran this by longtime death row assistant federal public defender Robin Konrad, former director of research and special projects with the Death Penalty Information Center. State officials have given her both reasons, she said, but it was her belief that, yes, they were seeking to avoid unpleasant visuals and the likely outcry that could result.
That convulsions are visually disturbing is the operative principle behind an unusual frightening agent called Avitrol. As used by farmers, the chemical is applied to a tiny percentage of a bait scattered in the fields, maybe one in a hundred pieces. The lottery loser who eats it takes to the air, flapping and squawking and soon thereafter convulsing grandly and dropping dead. The idea is that the rest of the flock, witnessing the spectacle, would be spooked and flee the farmer’s field.
In 1975, Ontario’s minister of the environment declared that only pesticides shown to be humane could be applied in the province. Though Avitrol is used as a frightening agent, it is a poison and so was included in the testing. The convulsions, said the University of Ottawa report on the results, happened after the point at which an EEG indicated a lack of awareness similar to that caused by dissociative anesthesia. The team deemed Avitrol humane but warned that the scientific evidence would “never change the opinion of those observing the effects.”
About that, they were correct. On YouTube, there is, or was, a video of a pigeon on Avitrol. Commenters assumed the bird was suffering and posted messages of pity and outrage. (At least the women did. Men’s posts were more along the lines of: “Where can I buy this stuff?” And: “Maybe they shouldn’t shit on everything and this wouldn’t happen to them.”) It seems the theatrical death throes of Avitrol victims are more upsetting to people than to other birds. In studies comparing its effectiveness with that of common frightening devices, the chemical placed last.
USDA Wildlife Services deploys a cyanide device on behalf of ranchers who complain about coyotes. The original was developed in the 1930s, and was known as the Humane Coyote Getter. It’s a buried cyanide ejector, triggered by tugging on a bait that protrudes from the ground. Assuming it is jaws that do the tugging, the poison ejects directly into the mouth, à la an OSS cyanide pill.
You kind of knew there was going to be trouble. In a U.S. Fish and Wildlife Service study spanning 1940 to 1941, the Getter compared favorably to leghold traps in terms of humaneness—what wouldn’t?—and the toll on nontarget wildlife. But the Getter got seven cows and twenty-four pet dogs over the course of that year, and so began its undoing. Between 2013 and 2016, the updated version, called the M-44, killed twenty-two pets and farm animals, and it has, over the years, injured a number of humans, including a man who mistook it for a geodetic survey marker he wanted to steal. At least one lawsuit is pending, and four states have banned M-44s. Sayonara, cyanide.
Warburton and I are walking along rows of enclosures. Most are empty. A few possums are asleep in hanging burlap sacks, which, he says, remind them of the mother’s pouch. We’re talking about a common and inexpensive rat poison, an anticoagulant.
In small doses, anticoagulants are used to prevent blood clots—in, say, patients laid up in bed after surgery. (When my brother, Rip, was prescribed warfarin, he texted, “I’m taking rat poison,” and he was.) In larger doses, anticoagulants interfere with the kind of clotting that patches tiny breaches in the capillaries—the normal wear and tear of the circulatory system. Animals that consume anticoagulants bleed to death internally, and that, Warburton says, is an unpleasant way to die.
