Darwin's Bear

One of my favourite parts of Origin of Species is in Chapter 6, where Darwin reflects on the difficulties of his theory:

In North America the black bear was seen by Hearne swimming for hours with widely open mouth, thus catching, like a whale, insects in the water. Even in so extreme a case as this, if the supply of insects were constant, and if better adapted competitors did not already exist in the country, I can see no difficulty in a race of bears being rendered, by natural selection, more and more aquatic in their structure and habits, with larger and larger mouths, till a creature was produced as monstrous as a whale.

I like this passage because it suggests that the actions of the bear are a motor for its evolution, tying together environmental conditions (insects) and mutations (of the mouth). Without the actions of the bear, the mutations would likely be harmful or of no benefit, and the bugs in the water meaningless.


Darwin released several editions of Origin of Species with passages added and removed. Most modern editions reflect the first edition- in some ways, the boldest edition, with the least removed.

So, after doing a little research, I was surprised to find out that the bear passage was one that Darwin had removed- and then restored. Evidently, he felt that the role of action was suggestive of Lamarck's work (ex. the giraffe that stretches its neck to reach plants passes that longer neck down to its offspring).

Only, I think not. Lamarck was making a claim that the muscular development associated with actions of the parent were inherited by the offspring. Darwin is claiming that in the context of certain action patterns, new developments would become beneficial and evolution might occur.

This is quite forward thinking. Stephen J. Gould proposed something similar (albeit as a stabilizing influence on evolutionary change) with habitat tracking. Here, action, namely animals following a changing climate, slowed evolutionary change. Others, like Jean Piaget, Susan Oyama, and Gilbert Gottlieb have also claimed an important role for action.

I also like this passage because I think it's pretty cool that whales evolved from land mammals. I think I first learned about that at the Whaling Museum in New Bedford, MA.