I’ve got two stories in the New York Times tomorrow, at two ends of life’s scales.

In the cover story, I write about smiles. Faces have long fascinated me (see this Discover column on Darwin and Botox), and so I was intrigued to come across this recent paper focusing on smiles in particular. I talked to David Corcoran about the story for the first twelve minutes of the latest Science Times podcast.

Elsewhere in the Science Times, I keep up with the creepiest form of life out there: infectious cancer. Two species–Tasmanian devils and dogs–have given rise to cancer cells that can hop from host to host. I wrote about Tasmanian devils in the Times, and about dogs here at the Loom. Now there’s news that the dog cancer (which I want to call Canis cancer after talking to the scientists who study it) rejuvenates itself from time to time by stealing its host’s mitochondria. This is a story that just keeps going and going…like the cancer themselves.

Originally published January 24, 2011. Copyright 2011 Carl Zimmer.