Well, it turns out that pakicetids, known to you and I as the earliest known whale ancestors, had vegetarian ancestors of their own. This week's Nature has an article about Indohyus, a new deer-like terrestrial whale from India. The creature can be identified as a whale based on the structure of its middle ear. Surprisingly, it is herbivorous. Pakicetus, Ambulocetus, and all the other whales are carnivorous, so one would expect that whales came from a carnivorous ancestor. Such, it seems, is not the case.
More surprisingly, this is the first time in MY experience that an herbivorous animal has gone back to being carnivorous. The evolution of herbivory requires several changes in the body, including the gut, dentition, behavior, and metabolism. To go BACK to carnivory seems like a waste of all that effort. Indohyus supposedly fed on water-based vegetation. Why did whales so quickly turn to meat? Are there not enough plants underwater?
And then, of course, there's some exciting marsupial news: It turns out that kangaroos didn't always hop. Early versions galloped. Nambaroo gillespieae is a virtually complete early kangaroo that ran on all fours, may have had an arboreal streak, and had "fangs." Despite the fearsome dentition, Nambaroo was still a vegetarian at heart.
Indohyus is in this week's Nature, and Nambaroo is in the Journal of Paleontology. If any of you out there in Readerland have access to these journals, I would greatly appreciate the PDF.