Living with Animals

We've been living on a wooded lot that adjoins a forest park for a few years. Consequently, there are lots of animals around all the time. Also, I feed the birds, plus critters are attracted to the food. All the mammal and bird species that are in Northeast Ohio hang around our yard day and night.

Over time the animals get used to us walking around the property. It's setup a scenario that gives an advantage to the least people-averse animals. Consequently some of them are significantly tamer than others and will walk right by me in the early morning twilight, or will hang out within a few feet of me without being overly alert. Also some of the animals, like the turkeys and the squirrels, have seen us around since they were very young. I'm guessing they'll get more and more tame as the generations go by. My hypothesis is they'll also transform the property and boost the soil fertility in a positive feedback loop but that process will probably be too slow to perceive year to year.

Anyway, the point of this post is that those animals aren't just transforming the property, they're also working on us. A great example of human and animal co-evolution is offered by lactase persistence. Another example, and less obviously beneficial example, is the transmission of diseases from animal and human populations. Diseases can mutate and jump from species to species. I'm pretty regularly in contact with objects the animals have been on/around. It's not too hard to imagine transmission of a disease from them to me and vice versa. I'm sure the same mechanism is in operation all the time among people who are working with domestic and wild animals on a daily basis.

When people are in constant contact with animals, there's a much higher chance of viruses jumping from one population to the other. I've wondered if that's one mechanism of rapid genetic change and, to put it bluntly, human population replacement by disease. That is, a group that's been living in one disease-environment can move in a displace another group with no immunity.