Why am I warm blooded?

Why am I warm blooded?

Author: BBC World Service August 21, 2026 Duration: 26:28

CrowdScience listener Matt wants to know why he's warm blooded. He started thinking about this when he was watching some ants during the recent heatwave in Europe and wondered why their blood didn't boil. What are the pros and cons of being warm-blooded like us or cold-blooded reptiles like lizards?

Caroline Steel meets evolutionary biologist Dr Manuel Leal from the University of Missouri in the US, who explains the differences between ectotherms (cold-blooded animals) and endotherms (warm-blooded animals). She discovers that the terms cold blooded and warm blooded are actually misleading, because reptiles can reach a high body temperature and some might even become warmer than us.

She talks to Simon Hodder, Professor of Environmental Ergonomics at Loughborough University in the UK, who describes how our bodies regulate heat, how we cool down when we get too warm and how that's all controlled by our brains.

Caroline also gets to meet some hedgehogs in the wild with Julia Nowack, an ecophysiologist from Liverpool John Moores University, who researches thermoregulation and is monitoring hedgehogs when they hibernate. Changing body temperature is one of the ways that some endotherms survive the winter when it's colder and there's less food around.

So who has the advantage? The warm-blooded endotherms who can heat their own bodies or the cold-blooded ectotherms who rely on the sun? Reptiles can get away with eating very occasionally while mammals and birds have to keep fuelling their energy with food to keep the heat going. That means we can live in most climates and have a better chance of escaping predators, but is it really best?

Presenter: Caroline Steel

Producer: Jo Glanville

Editor: Ben Motley

(Photo: European hedgehog (Erinaceus europaeus) adult animal in a snow covered garden in winter, England, United Kingdom - stock photo Credit: imageBROKER/Kevin Sawford via Getty Images)


Curiosity drives discovery, and CrowdScience from the BBC World Service is built entirely on that principle. Each episode begins not with a scripted lesson, but with a question sent in by a listener from anywhere in the world. These aren't simple queries with easy answers; they are the wonderfully complex, often quirky puzzles about everyday phenomena and cosmic mysteries that make us all stop and wonder. What does silence sound like? Could we ever photosynthesize like plants? How does a crowd's mood physically spread? The team then embarks on a genuine investigative journey, tracking down the specialists at the very edge of our understanding-neuroscientists, ecologists, physicists, and engineers-to piece together credible, compelling answers. Listening to this podcast feels like having a direct line to the labs and field sites where knowledge is being created. The conversations are deep yet accessible, transforming abstract concepts into relatable stories. It’s a collective exploration where listener curiosity sets the agenda, making each episode a unique and democratic look at the machinery of our world and beyond. You become part of a global community pondering life, Earth, and the universe, one thoughtful question at a time.
Author: Language: English Episodes: 50

CrowdScience
Podcast Episodes
Can we cancel light waves? [not-audio_url] [/not-audio_url]

Duration: 26:28
Noise cancelling headphones filter out sound waves that we don’t want to hear. Listener Ahmed in Libya loves wearing his and, as he was listening to them, he had a thought: ‘Could we cancel out light waves in a similar w…
Do multiple choice questions make us biased? [not-audio_url] [/not-audio_url]

Duration: 29:01
CrowdScience listener Griffith in Ghana, isn’t JUST a CrowdScience listener. He’s also a listener to our sister show on the World Service, Unexpected Elements. But he’s noticed something funny. In the weekly Unexpected E…
Why do I tan more in the US? [not-audio_url] [/not-audio_url]

Duration: 26:28
CrowdScience listener Namrata and presenter Chhavi Sachdev have something in common. They both get more tanned in the summer in the United States than back home in India. Namrata wants to know why she came back from her…
Do fish know what they look like? [not-audio_url] [/not-audio_url]

Duration: 26:28
There’s something fishy going on in the Czech Republic, where CrowdScience listener Ian lives. He keeps tropical fish, and he’s noticed that when he adds new ones to his tank, they swim with others of the same breed. He…
Why do I find silence unbearable? [not-audio_url] [/not-audio_url]

Duration: 26:27
Is silence blood-curdling or blissful? CrowdScience listener Ziqi finds it intolerable and thinks that there’s a good reason for it – silence is so rare in nature that it could be a signal for danger. Presenter Marnie Ch…
How do cicadas know what season it is? [not-audio_url] [/not-audio_url]

Duration: 26:29
Crowdscience listener Ryosuke grew up in Japan, and spent his childhood summers catching cicadas in the park. For people in Japan, the sound of their chirping signals the first true summer day. But until they emerge, the…
Did I inherit my laugh? [not-audio_url] [/not-audio_url]

Duration: 26:28
CrowdScience listener Limbikani in Zambia is always being told he has his Dad’s laugh, so he set us the challenge of trying to find out whether a laugh can be passed down in our genes or if it’s something we learn from o…
The CrowdScience quiz of the year [not-audio_url] [/not-audio_url]

Duration: 35:57
In 2025, the crack team of intrepid presenters here on CrowdScience have been on some incredible adventures. They’ve wondered whether water is wet, and gone a hunt for a missing tangerine. They’ve wondered why animals sw…
How do we adapt to the cold? [not-audio_url] [/not-audio_url]

Duration: 26:29
When some people are wandering around in shorts and a t-shirt, others are wrapped up in warm coats and jumpers. How come our responses to cold weather are so different? People have been living in cold environments for th…
Can you play the guitar underwater? [not-audio_url] [/not-audio_url]

Duration: 26:29
Smashing up guitars is a classic rock star activity, but how about drowning them? Seven-year-old listener Cornelius asked CrowdScience to find out what happens if you play a guitar underwater. Could this be the next avan…