According to the experts who know lots of stuff, at various times throughout history, different human species lived concurrently, or overlapped. Up until about 12,000 years ago, our lineage shared the planet with other, closely related species... including uncles. And now, for the first time in recorded history, I present to you some recent illustrations created for the Review section of The Wall Street Journal. This has been a weekly column illo for most of the last year. Many thanks to Christian Drury for the assignment(s), as well as Kelly Peck, Lisa DiLillo, Marlene Szczesny, and Kris Areche. Columns written by Matt Ridley.

This column was about increased human mutual interdependence.

“When Scientists Confuse Cause and Effect”

"A New Look at the Biology of Cruelty". According to psychologist Simon Baron-Cohen, the author of a new book called `The Science of Evil’ (and cousin of comedian Sacha Baron Cohen),"in most cruel people the “empathy circuit,” which runs through 10 different regions of the brain, goes down either temporarily or permanently, leaving the person with “zero empathy.” The reasons may be partly innate, partly to do with early experience such as birth trauma or parental neglect, or often an interaction of the two".

One of the main causes of species extinction is... predators (or competitors, or parasites), rather than loss of habitat. (But in this case, perhaps a little of both.)

"Why Frogs Don't Sing Like Sinatra". Female Tungara frogs are attracted to males with complex songs.... but cannot tell the difference between elaborate songs and slightly more elaborate songs'. Scintillating.

"When Precaution Trumps Public Safety". Ridley discusses food irradiation and qoutes Dr. Michael Osterhol, director of the Center for Infectious Disease Research and Policy at the University of Minnesota: "irradiation is the necessary fourth pillar of a public health platform that has delivered the astonishing result of a day of longer lifespan for every three days of time during the past century: chlorination, vaccination and pasteurization being the other three barriers to infectious disease". A lot of concerns over the use of irradiation are out of date. In the past, cobalt-60, a gamma-emitting radioactive isotope, was used as a source of the radiation for food, which tainted the whole enterprise with radioactive words like `gamma’ and `radioactive’.

Whatever happened to jetpack travel?

“Cheapeners deserve as much credit as inventors”... "A feature of innovation is that the greatest impact of a new idea comes not when the light bulb goes on over the geek’s head, but when the resulting technology eventually becomes cheap enough for many people to use—perhaps decades later".

This one was on studies of cancers that are contagious. Tasmanian Devils have developed tumors around the mouth and face (Devil Facial Tumor Disease, of course)- due to immune system inefficiency ("...devils being so inbred, having colonized Tasmania in small numbers more than ten thousand years ago, they cannot reject each other's tissue...") - and their proclivity towards biting each other on the face while fighting for food and during mating.