Why Black Bears Sleep in Trees

The ancestors of modern North American bears evolved in Asia during the Pleistocene, wandering over to Alaska during several appearances of the Bering land bridge, between the Bering and Kamchatka Peninsulas. Advancing and receding glaciers, fueled by evaporating sea water, caused ocean levels to alternately drop and rise, exposing and resubmerging the Bering Strait. The ancestors of black bears came across half a million years ago, and it is suspected that black bears adapted to climbing tr...

 Workplaces Conducive to Raising Children

We could also immediately change workplaces to allow for part-time work that has similar benefits and pay to full-time work and to allow for flexible hours and career paths. Our own workplaces, the universities, provide both very good and very bad examples. For years professors have worked at home and determined their own schedules with no loss of productivity. On the other hand, the career structure of universities is deeply in conflict with the imperatives of evolution—the years when we e...

 Weening Among Human Ancestors

Archaeologists have discovered that since the Pleistocene, humans lave always suckled infants for several years. Using biochemical analysis given human population when its children moved from breast milk to other foods. In one group of skeletons from South Dakota dated between 5500-2000 b.c., children were apparently depending on food other than mother's milk by the time they were twenty months of age.^' Recorded history also tells a similar story. Middle Eastern groups in 3000 B.C. were brea...