The size of brains in the animal kingdom is wildly different, from melon-sized in blue whales to pea-sized in shrews. But does a bigger brain mean a more powerful one? CrowdScience listener Bob wondered just this as he watched various sized dogs running amok in his local park: the Great Dane has a much larger brain than a Chihuahua’s, yet the job of ‘being a dog’ surely requires the same brain power. So why have a big brain if a small one would do? A search for the answer takes Geoff Marsh to dog agility trials, behind the scenes at London’s Natural History Museum and a laboratory that studies bumble bees. It turns out that size does matter, but not in the way you might think. Presenter: Geoff Marsh Producer: Dom Byrne (Photo: Great Dane HARLEQUIN and a chihuahua Getty Images)