Forbes has been tracking the world's billionaires since 1987 and this year there are more mega-wealthy individuals than ever before.
Killer whales whistle to talk to each other and click to find their way around. It's the echoes from these clicks that help the animals to map their surroundings and to pinpoint the location of their next meal.
The University of Helsinki team gathered 30 years' worth of genetic and population data on tawny owls. They found that the birds inherited their plumage colour from their parents.
Known as Watson, the computer is a giant piece of hardware, equivalent in size to several fridges. And over three programmes, Watson beat his human contenders with ease.