A few years ago, scientists in the Bahamas introduced curly-tailed lizards, a predatory species, to an ecosystem containing two types of anoles, both peacefully co-existing lizards (and both prey for the predatory curly-tail). Scientists would have previously expected that the predator would quickly gobble up the anoles, but their ultimate downfall was unexpected. The prey species responded to the introduction of the predator by changing their behavior — one species fled into the trees, resulting in increased competition for food between the two previously harmonious co-existing species. The scientists hypothesized that it was the change in behavior, not the predator physically eating up all the other lizards, that ultimately threatened the prey lizards with extinction.

To summarize: The change in the prey’s behavior turned out to be more devastating than the predator itself.

What does this have to do with towns? We live in an urbanized ecosystem, in a complex and delicate balance with many moving parts. Once upon a time, the fastest vehicle available in a city was a horse and wagon. Now, I won’t sugarcoat it; horses created a lot of muck and were a sanitary hazard, and horses weren’t totally safe; today, equestrian fatalities are slightly lower than skiing fatalities. But, we can at least say that they were slow, probably maxing out around 10-20 miles per hour.

Humans evolved over millions of years with animal and vehicle speeds that rarely exceeded 20 miles per hour. Then, all of a sudden, cars came about, and within a few decades, they had gotten so fast and heavy — and therefore so deadly — that they quickly became a menace — and induced changes in behavior. Before cars came around, children regularly played in the streets. That’s just what children did, probably for millennia. Children started being killed by cars so often that cities started erecting monuments to the fallen.

Over the course of the twentieth century, children became less and less a fixture of public life. In 1969, nearly half of children walked or biked to school; 40 years later, that portion had declined to only 13%. Of course, increased distance between home and school has surely been a factor. But clearly the lack of safety for children plays a large role. Even the proliferation of playgrounds is a twentieth century phenomenon, as a direct result of streets being taken over by dangerous cars.

Today, thankfully far fewer children are being killed by cars. But we do have a loneliness epidemic, which was happening even before the pandemic. Perhaps the fact that our public spaces are dominated by dangerous, loud and dirty cars, is a factor?

Here’s the point — making streets safe is about eliminating deaths, yes. But, it’s also about how we choose to shape our lives. The introduction of a predator into our ecosystem a century ago dramatically altered human life. Some benefits have been found of course, but there have been many unexpected costs. Perhaps it’s time to stop gorging the predator with so much energy and space, and do some ecosystem re-balancing.

For more of Sweeten the Streets, visit Ella Kondrat's Substack here.