I have always been fascinated by evolution, and while I can usually see why and how certain characteristics evolved in different species, I’m confused by whales and dolphins. How did their breathing holes evolve, bearing in mind their ancestors were land mammals?
• Blowholes are paired nostrils that evolution has shortened and redirected towards the most convenient spot for snorkelling – the top of the head. They do not pass through the brain, though.
As in most swimming, air-breathing vertebrates – such as frogs, crocodiles, capybaras or hippos – whales’ nasal openings, or nares, are placed high up so they can breathe…
