Trivia: Which of these statements is true about mammals?
They didn’t live alongside dinos
They’re the largest animal group
No mammal is cold-blooded
No mammals lay eggs
The correct answer is No mammal is cold-blooded
So why is this answer correct? : Although early mammals were cold-blooded for tens of millions of years as they evolved from reptiles, today, no mammal is cold-blooded. All mammals — and also birds — are capable of generating internal heat and are known as “homeotherms.”