Toronto Star Article:
Here's an excerpt:
"The colder and snowier it gets, Canadian scientists have discovered, the more penis length matters for mating success.
A study of mammals from around the world has found that the species with the best-endowed males live in polar regions, rather than in more equatorial climes.
That's because a longer penis increases the chances of being the successful father when females mate with a succession of different males, say researchers Steven Ferguson and Serge Larivière in the current issue of Oikos, a Nordic scientific journal."
Later in the article:
"It makes so little sense to have a bone there because fractures are common, and if the penis bone breaks, you're out of business for that mating season — and maybe longer."
Larivière says the bone adds support to the penis but is not essential for copulation.
Instead, "baculum size serves as an indictor of male quality.
"If a female encounters a dozen males at the same time, she can evaluate them as potential fathers and make a choice. "