Blue whales and orcas are both specialists in their own way. You can’t really measure which one is more intelligent.
We don't know for sure which one is smarter, because not everyone agrees on what "intelligence" means. Both have their own special behaviours and skills and we can't say who is more intelligent.
Two southern resident killer whales surface near Saturna Island, B.C, in September 2012.
A bold new approach could protect endangered animals.
A female resident orca whale breaches while swimming in Puget Sound in January 2014.
THE CANADIAN PRESS/AP, Elaine Thompson
Noisy waters may be making it harder for southern resident killer whales to communicate with each other and find their food.
How do animals think and feel?
Patrick aka Herjolf
A growing body of evidence points to how animals are aware of death, can experience grief and will sometimes mourn for or ritualize their dead.
An animal behaviour expert gives his view on finding that a killer whale can copy the sound 'hello'.
Hey, what about us? Whale shark (spotted) and manta ray, a close shark relative.
As the Discovery Channel and National Geographic Wild unleash a week of dueling shark programs, a biologist advises viewers to take what they see with a large grain of sea salt.
Remembering a giant haunted by tragedy.
No more breeding, but still on exhibit.
The history of displaying exotic animals seems to be one of evolving public expectations about what constitutes acceptable conditions. Is it a case of the more things change, the more they stay the same?
Mike Blake / Reuters
No one wants animals to suffer, but it is notoriously difficult to measure their welfare.
Documentaries are fragile things, easily blown into obscurity or silenced by the sheer weight of corporate power.