Tomorrow’s Science Times section of the New York Times has a special package of articles all about animals–the relationship between humans and the animals we raise, what makes us separate from animals, and so on. I took the opportunity to take a big step back and look at how animals came to be in the first place. The answer–or at least part of it–lies among some weird creatures, such as this tentacled creature that dwells inside snails. Check it out.

Originally published March 14, 2011. Copyright 2011 Carl Zimmer.