Pooping in the news: Why other animals don't need or use toilet paper
Pooping positions have recently been in the news, especially a recent study about how dogs line themselves up with the Earth's magnetic field when they urinate and defecate (please see "Dogs Line Up With the Earth's Magnetic Field to Poop and Pee").
A recent discussion in New Scientist magazine called "The bottom of it" (as of now only available to subscribers) caught my eye. It began with an interesting observation and two questions as follows.
Non-human animals do not use lavatory paper, and those that I have observed don't appear to need it. Are there anatomical reasons for this? If so, why is our anatomy not similar to that of the great apes? Has our invention of lavatory paper, and whatever methods preceded it, meant that we have lost an anatomical feature that we once had?
Two answers were provided by Christine Warman who lives in Saltburn-by-the-Sea, North Yorkshire, UK, and Tony Holkham who lives in Boncath, Pembrokeshire, UK.
Ms. Warman notes, "Although we share most of our DNA with great apes, there are some striking anatomical differences between ourselves and our nearest relatives, most notably our vertical posture. This enables us to walk tall with our hands free, but it also comes at a price: we experience problems with our back and joints, and the whole business of evacuating our waste is more difficult. The fundamental problem is that the area used for releasing urine and faeces is compressed between thighs and buttocks, so we are more likely than other animals to foul ourselves. We also differ from other animals in our response to our waste, which we tend to regard with disgust. This seems to have developed as a result of living together in settlements rather than roaming through the forest, where we could leave our mess behind us. Unlike other primates we can learn when and where it is acceptable to excrete."
Watching cats "play the cello"
Mr. Holkham likewise offers some interesting views. He writes, "Wild animals, especially carnivores whose faecal matter contains material attractive to pathogens, have evolved to be able to clean themselves. You only have to watch cats 'playing the cello', as it is colloquially called, to see how proficient they are at grooming their rear. Parents will clean their young until they are supple enough to do it themselves. Adult animals will also groom each other, forming social bonds at the same time." For more on cats "playing the cello", AKA cleaning their behind, please click here.
He also writes, "Domesticated animals selectively bred by us are a different case. My dog, for example, cannot clean his hind quarters because he is too short and stocky in the body; we have to check that he is clean after he has defecated. Similarly, sheep have to be inspected regularly because their body shape prevents them from keeping themselves clean. Many species, humans included, have adapted their front legs to be hands—helpful for self-grooming. The use of plant material to clean the anal area would have been an evolutionary adaptation. Vegetable matter was substituted with a sponge on a stick in Roman times, and more recently with paper."
Matters of "the bottom" define us
We are indeed exceptional in matters of "the bottom" but not in many other areas so to speak. Standing tall has a downside.
The teaser image can be seen here in an essay called "Defecating dog sparks US shootout".
Marc Bekoff's latest books are Jasper's Story: Saving Moon Bears (with Jill Robinson; see also), Ignoring Nature No More: The Case for Compassionate Conservation (see also), and Why Dogs Hump and Bees Get Depressed (see also).