Earlier this year, the BBC had a series, a co-production with NGC, called Planet Earth Live, where the commentary by Richard Hammond (of Top Gear fame) and Julia Bradbury were on location in different parts of the world. Obviously the whole show isn't live but at least we didn't have to wait 3 years to get the series broadcasted. And I'm sure they learnt a lot from the NGC fiasco with the "live" show in South Africa about sharks.
One of the show's main story lines was the Grey whale migration up the North American Western coast. The Grey whales are migrating toward the feeding grounds in the Northern Pacific/Behring Seas area after calving Mexican waters. This means there are plenty of mothers traveling with calves along the route. There are pods of Orcas which target calves all along the coast as well.
During one such attack in Monterey Bay, the BBC documented, for the 2nd time, Humpback whales intervening with the Orca attack on a Grey whale calf. The 2 humpbacks repeatedly got between the Orcas and the calf, pectoral slapping to prevent the Orcas from killing the calf. They failed but then they hounded the Orca pod for a while longer so they couldn't feed easily.
http://www.bbc.co.uk/nature/17991601
According to observers, over 100 Northern Pacific Humpbacks came into the area, trumpeting and harassing the Orca pods in the area. In fact, the Orca pods left Monterey Bay and started feeding outside the bay. Could the Humpbacks have driven out the Orcas? Were they policing the area? In the Antarctic, for the Frozen Planet series, the BBC captured 2 Humpbacks defending a Weddell seal from Orca attacks.
I am not a fan of Deep Ecology or any anthropomorphic associations and there are scientists who believe that Humpbacks are just a step up from cows in intelligence. Julia Bradbury put a very anthropomorphic slant by reporting that one of the Humpbacks n that scene was identified to have been attacked by Orcas before, and thus could've been reacting because of that. A bit of a stretch for me to believe that! But hey, it's a theory!
What's more interesting to me is the inter-species mingling. In 2 documented incidents, Humpbacks were drawn into an Orca hunt. Were they just curious, just like when Humpbacks come right up to boats and interact with divers and snorklers? Or was there a definite agenda of intervention, to "thwart" the Orcas? Is the "Maternal instinct" universal in the mammalian world? 
Impossible to say but fascinating nonetheless!
