By Bill Lawyer
Several years ago I wrote an article for this newspaper in which I described the ways that wildlife could help us deal with the threats of climate change. I focused in particular on the example of opossums. These fascinating and commonplace animals can indeed teach us many lessons.
Not by communicating directly with us, of course, but in the way they live their lives.
The most important lesson is that the existence of marsupials in North America is in itself an amazing example of adaptation and the ever-so-gradual but inevitable change in life on planet earth.
Marsupials represent one way that natural selection “covers its bets” by creating more than one way for mammals to nurture their young.
And then there’s that prehensile tail. It acts like an extra arm, wrapping around tree limbs for stability. A few years back there was a young opossum so attached on a branch of a lilac bush in my backyard. It stayed there for several days, although it would come down for a while, eat, and then go back up.
Millions of years ago there was one large super continent that was a breeding ground for a wide range of animals. While many became extinct, those more flexible found ways to keep going. Opossums were mainly confined to South America, but during an ice age about three million years ago they moved north. And as climate change has raised temperatures, areas that were too cold for opossums are now quite hospitable.
They are considered to be nocturnal, but as the days grow longer in the summer months, opossums can often be seen at dawn and dusk.
What brought this to mind was walking outside my house, and noticing a young opossum rustling through the bushes looking for food. I stood there watching as the opossum carried out its foraging, then moved next door to my neighbor’s yard.
In the case of opossums, they can eat just about anything — from berries and fruit to slugs, snakes and even small mammals. This also helps them to adapt. And then there’s their “playing possum” defense mechanism.
What is more exciting is that recent research has shown that they consume large quantities of ticks. A research team at the Cary Institute For Ecosystem Studies in Milbrook, N.Y., learned this somewhat accidentally.
Back in 2014 the team was carrying out research on which mammals were most likely to carry the disease vectors that are transmitted by ticks to humans. Each species was given 100 ticks, surveyed to see how many became attached and of those how many had the disease.
What turned out was that in the case of opossums, nearly all the ticks disappeared, but very few transmitted the disease. In checking the stool samples, they found that with opossums, nearly all the ticks had been eaten.
While some of the ticks were eaten as they were foraging for food, many of them were eaten because of the fastidious nature of opossums — like cats, they spend much time grooming themselves. Any ticks that got in the way were “down the hatch”.
Of course, opossums aren’t the only animals that eat ticks. To some extent, so do guinea fowl, as well as chickens and turkeys. The big advantage of opossums is that they eat lots of ticks and are already “native” to Rye.
So it’s clear there are many things we can learn from opossums. And, as temperatures rise, there will be a lot more of them to learn from, right in our backyards.
An opossum disturbed while foraging in a field