Ever think about how we humans make animals feel? As pets, they provide us with companionship and as creatures of commerce they give us sustenance through various resources and products, but how do we make them feel? Or is it silly to imbue animals with characteristics, like feelings or emotions, that only humans are capable of having?
Recent research on two types of animals, one wild and the other domesticated and commercialised, sheds what I think is some interesting light on these issues.
In a paper published in the Journal of Endocrinology in July, a group of experts in animal science and dairy science (yes, apparently there is such a thing) from the USA and Switzerland describe the effects of injecting pregnant milk cows with a chemical called 5-HTP (5hydroxy-L-tryptophan). It’s what they call “the immediate precursor to serotonin synthesis” – in other words it’s a substance that the body converts into serotonin.
Serotonin itself is, of course, a natural feel-good chemical, and media commentators have suggested that one of the benefits of this study is that it made the cows – a dozen Holsteins and a dozen Jerseys – happy.
Sounds adorable, doesn’t it. I suspect that the researchers themselves aren’t particularly interested in their test subjects’ supposed mental state. The actual aim of their study was to find a way to prevent a condition called hypocalcemia, which involves low levels of blood calcium and is especially common in cows that are transitioning from pregnancy to lactation. It’s a disorder that may result in digestive and immunological problems, lowered pregnancy rates and longer intervals between successive pregnancies.
The outcomes of the study appear to be promising. Daily 5-HTP injections made for healthier cows and raised the concentration of serotonin in the blood of some of them. The “happier” cows also tended to produce more nutritious, more calcium-rich milk.
So here’s the positive spin on this story: modern veterinary science makes for more joyful cows and better milk. The much darker back-story is that the majority of modern commercialised dairy cows are little more than milk producing machines valued only as financial assets. They need to be kept pregnant pretty much constantly in order to produce as much milk as possible. This is achieved by dosing them with a variety of chemicals. Does that make them happy? You tell me...
Another, completely unrelated study, illustrates a different way in which humans are affecting animals. It would appear that birds that live in cities are noticeably angrier than their more docile country cousins.
When researchers simulated intrusions of foreign males into the territories of male song sparrows in suburban areas of Virginia in the USA, the birds tended to defend their turf much more vigorously than males of the same species living in rural surroundings. The scientists found no obvious correlation between this aggressiveness and testosterone levels or population density and suggest that the more limited availability of breeding sides in urban areas may be to blame.
"Suburban sprawl is a primary form of human habitat change,” explains Kendra Sewall, one of the co-authors of the paper, “and though many species can survive in our backyards, their behaviour and physiology may change to cope with shifts in resources and with new disturbances." So, by creating cities that are less bird-friendly than natural habitats, we’re making birds “angry”? I guess so.
Clearly we are constantly affecting the lives of animals, both wild and domesticated, in many direct and indirect ways. “So what?” you might say. You can, of course go through your own life blissfully unaware of the impact you’re having on theirs, but I recon it’s worthwhile, every now and again, to take stock of how we treat and interact with other creatures. Don’t you think?
- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath
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