4. Gut Feeling

Evolutionary biologist, comedian, and aspiring Dr Frankenstein Simon Watt is on a quest to improve the human body, with a little help from our animal cousins.

In each episode he turns his imaginary scalpel on a different human organ and wonders if we wouldn’t be better off with something slightly different – the eyes of a chameleon for example, or the heart of a Greenland Shark!

Our bodies are essentially a long squishy tube, with a mouth at one end, and an anus at the other. Everything else is mere detail. What we put in that tube can make the difference between a life of good health, and a night locked in the bathroom. Dr Mads Bertelsen from Copenhagen Zoo introduces us to a creature that can digest things that would kill us; the vulture. Eating rotting meat's nothing, when you have stomach acid the strength of a car battery.

If meat's not your thing, you might want to switch out your digestive tract with that of a herbivore. A ruminant. Or to be more precise, a cow. Dr Cate Williams from Aberystwyth University imagines what we could do if we had a 'rumen', the unique organ that gives these massive, docile 'foregut fermenters' the ability to break down the toughest plant matter with no problem. For them, it's all about the microbes. Millions of them.

And if all this digestion sounds a bit too much like hard work, why not take a leaf out of the book of a Saccoglossa, a leaf-life, photosynthetic sea-slug who's mastered the art of photosynthesis. Christopher Howe from the University of Cambridge explains how they do it, via a gut system which has evolved the ability to steal chloroplasts, the photosynthetic cells from algae, and make them their own.

Producer: Emily Knight

A BBC Audio Bristol production for Radio 4, first broadcast in August 2021.