What’s that? You’ve never heard of Sgt. Macaque or Dr. Shepherd? Well that’s probably because I just made those names up.
I did so, however, based on two very real headlines that I happened across in the past few weeks. Both are fascinating examples of humans taking advantage of other species’ adaptations to help us meet our goals, and both got me thinking about the prevalence and significance of this kind of human/animal ‘partnership.’
Headline #1: “Meet the Monkeys Keeping Chinese Troops Safe”
For those of you not inclined to click on the link, I will summarize. The People’s Liberation Army of China (aka the Chinese military) has revealed that a small unit of trained macaque monkeys is being used at one of the country’s Air Force bases to prevent migrating birds from nesting in the area and potentially getting sucked into aircraft engines (an occurrence that is good for neither the bird nor the aircraft/pilot). According to the PLA, the monkeys, which are trained to destroy birds’ nests in response to whistle commands, are proving a more effective deterrent than scarecrows, netting, firecrackers, or human soldiers. Not surprising, given that monkeys have evolved to be more adept at arboreal maneuvering than men of either flesh or straw.
And in other news…..
This one is pretty self-explanatory. Researchers in Italy trained two German Shepherds that had previously worked as explosive-sniffing dogs to recognize the scent of volatile organic compounds — chemicals associated with cancerous tumors — in urine samples. In a subsequent blind study of almost 700 men, the dogs correctly identified which urine samples came from men with prostate tumors 98% of the time. This success echoes previous research with medical detection dogs, which has found evidence that dogs can detect lung and breast cancers by smelling a person’s breath, and that they can be trained to warn individuals with diabetes or epilepsy of low blood sugar or impending seizures.
Considered alongside the other tasks in which dogs aid humans (some, such as search-and-rescue efforts and drug-sniffing, are well-known; others, such as identifying diseased beehives, sniffing out bedbugs, and tracking orca poop, are not), two inescapable conclusions appear:
1. Dogs have an amazingly good sense of smell. Their noses contain up to 300 million olfactory receptors (ours have a measly 6 million), and a substantial portion of their brain is devoted to analyzing the smells registered by those receptors. This means that they can smell in parts per trillion. Imagine being able to smell one drop of blood in 20 Olympic swimming pools worth of water (sharks, by contrast, smell in parts per million or billion), and you’ll start to get an idea of how natural selection has honed this adaptation in canines.
2. Humans are good at co-opting it.
Humans, in fact, have created quite a niche for ourselves by exploiting other animals’ abilities. And we’ve been doing it for a long time. Recent evidence suggests that humans have been co-evolving with dogs, the first domesticated animal, for 30,000 years. The domestication of farm and labor animals was more recent but, as evolutionary biologist Jared Diamond has thoroughly explained, it has had an enormous impact on the development of human societies over the past 10,000 years. The truth of the matter is that humans just wouldn’t be where we are today if we didn’t have these conscripts.
But here, I think, is where it is worth making a big distinction between the subjects of the two headlines above. Macaques are not domesticated. Nor are a variety of other species that humans have put into service more recently, such as military marine mammals. And this raises some major ethical dilemmas. Is it okay for humans to use animals in this way? For decades, the US Navy has taken advantage of dolphins’ swimming and echolocation abilities to detect and clear mines (good for the human population), but military sonar has simultaneously contributed to making the ocean a more unhealthy environment (bad for marine wildlife). How much of a qualitative difference is there between this and the efforts of an organization like Helping Hands, which trains capuchin monkeys to act as service animals to the severely disabled? Under what circumstances, if any, does human need trump an animal’s (or species’) right to live undisturbed in its natural habitat? Do the “rules” differ for domesticated vs. non-domesticated species? As someone who has admitted to having a Grand Canyon-sized soft spot for animals, these are questions that I genuinely don’t have answers for, and I am curious to hear other people’s thoughts.
In the meantime, I will finish with one more current news story, this time about a handful of humans doing something to help out animals:
Medical Detection Dogs and the In Situ Foundation are but two of myriad organizations devoted to training dogs to use their noses in service of human health. Read this essay, however, for an alternative perspective on the use of dogs in medical detection.