We are hardly surprised by the slinking shadows or striped flanks we can sometimes glean through the thicket of prejudices that surrounds us. Distant growls do not trouble us. But a pair of unblinking eyes, an entire face bristling with whiskers, or the warm breath of a fellow creature of darkness may startle us. A brush of skin against skin is liable to make us outright jumpy. That is how dense and unyielding the thicket actually is.