teaching each other to attack boats
... that orcas have been teaching each other to attack boats?
... that <a href="./Orca" id="mwBlQ" rel="mw:WikiLink" title="Orca">orcas</a> have been <b id="mwBlU"><a href="./Iberian_orca_attacks" id="mwBlY" rel="mw:WikiLink" title="Iberian orca attacks">teaching each other to attack boats</a></b>?