- hardened or indurated, as by sclerosis.
"The swift's minute filoplumes would convey essential information on feather orientation to its brain; Foster's body hair ruffles empathetically. The urban fox engenders his deep respect: choosing to hunt, even though it could survive on pizza scraps. In contrast, humans seem 'sclerosed superspecialists.'"
- Carolyn Ristau, "Wild Things", 17 June 2016 Science (http://science.sciencemag.org/content/352/6292/1402)
No, I don't get it. In those examples, aren't the swifts and foxes specialized?