Which creatures have the highest and lowest internal body temperatures?

QUESTION Which creatures have the highest and lowest internal body temperatures?

Hummingbirds, the smallest of birds, maintain both the highest core body temperature in the entire animal kingdom, and the lowest for any endothermic (warm-blooded) animal, i.e. one that regulates its internal temperature.

On average, a bird's body temperature is several degrees higher than that of humans: their range is usually 39 to 43c (102 to 109f); and humans are closer to 37c. The Somber Hummingbird of Brazil has the highest recorded internal body temperature of 45c (113f).

In birds, insulation from the feathers, and the heat generated from hard-working muscles, both lead to a higher internal body temperature.

Smaller birds tend to have a higher body temperature in comparison with larger birds. This is because they have a small core volume to generate heat and exert more energy for flight. Hummingbirds can beat their wings a staggering 7,000 times per minute.

Burning all that energy during the day requires hummingbirds to lower their body temperature and metabolism drastically at night. They do this by dropping into an energy-saving state of inactivity called torpor.

The Peruvian Black Metaltail hummingbird is able to maintain its body temperature at just 1c above the surrounding air temperature.

J. K. Knight, Sudbury, Suffolk.

QUESTION Who coined the term 'identity politics'? 

The term 'identity politics' is attributed to the Combahee River Collective, a group of black feminists who published the Combahee River Collective Statement in 1977: 'This focusing upon our own oppression is embodied in the concept of identity politics. 

We believe that the most profound and potentially most radical politics come directly out of our own identity, as opposed to working to end somebody else's oppression.'

The term has gained prominence as a way to describe political activism and social movements based on shared aspects of identity such as race, gender, sexual orientation or other characteristics. 

It is highly controversial; many argue that it is divisive, emphasising differences rather than promoting unity.

Deb Wright, Henley-on-Thames, Oxon.

QUESTION What's the most ridiculous or funny school nickname you have ever come across?

Further to the earlier answer, when I joined a Dundee accountancy firm in my early 20s I met a lot of other great trainees, one of whom, Bruce (real first name Robert — a reference to the Scottish hero) became a lifelong friend. 

Bruce introduced me to one of his pals from school, 'Jerry'.

It was 20 years later, in my 40s, when Jerry took me aside and said: 'Ye know my name's no really Jerry, it's Alan.' 

It turns out he'd arrived at school one day with a haircut (done, I think, by his mum) that resembled a World War I helmet!

Johnny Watson, Glasgow.

Is there a question to which you want to know the answer? Or do you know the answer to a question here? Write to: Charles Legge, Answers To Correspondents, Daily Mail, 9 Derry Street, London W8 5HY; or email charles.legge@dailymail.co.uk. A selection is published, but we're unable to enter into individual correspondence