"Some wasps have learned to immobilise spiders and deposit their eggs inside of them."
I think many would get the wrong idea if they didn't click through and read carefully and skeptically. There's no evidence in the article that Orcas learned this shark vulnerability with any more sophistication or recency than the wasps did the spiders.
[0]: http://www.nature.com/news/2007/071214/full/news.2007.380.ht...
I can't think of a particular example offhand, but that sort of thing sure looks like learned tribal knowledge.
It's not as uncommon as you might think. There's crows that have learned to crack walnuts by shoving them under car wheels at stop lights, and they actually watch the lights, not just the cars, to tell when it's safe to walk in the street. It's not genetic; newly-introduced crows pick up the behavior from watching the existing flock.
Also, the articles on incentivizing crows to exchange coins or cigarette butts for food is quite interesting.