The breadcrumb navigation is irrelevant in terms of search engine optimization.
Clarification of above
(Speaking strictly as an SEO expert with thousands of #1 results on Google)
Although breadcrumb navigation (on page, not TITLE tag) includes the same number of links and the same anchor text regardless of the order, it is not irrelevant to SEO. The order in which links and even plain text appear within a page's source code DO make a difference, albeit usually slight.
Assuming all other factors being equal, a page with a "Lions" link near the top and a "Tigers" link near the bottom would generally rank higher for "tigers" than a page with a "Tigers" link near the to and a "Lions" link near the bottom.
Given that the breadcrumbs are inherently next to one another, the effect of the order is ALMOST negligible in practice, but it does have an effect. The more pages you have with any particular breadcrumb configuration, the more of an effect this has (although still nearly negligible for most sites in "real world" usage.)
When these same "breadcrumbs" (although not clickable) are inserted dynamically into the page TITLE tag, they have a much greater effect.
"Site.com / Mammals / Cats / Lions" is far superior to "Lions / Cats / Mammals / Site.com" in most situations, as the typical search would be more like "pictures of lions and other big cats" than "pictures on site.com of mammals who happen to be cats or lions". The order of these elements in a TITLE tag plays a huge role in SERP results.
Jake