- Scientists have measured the heart rates of many different mammals and a few birds, too. What did they learn? On average, the bigger an animal is, the slower its heart beats.
- Most animal hearts have an upper limit of about 1.5 billion beats. A mouse’s heart beats very quickly, so it uses up its 1.5 billion beats in just a couple of years. But an elephant’s slow-beating heart can keep on pumping for sixty years.
- Blood comes in a rainbow of colors. Some lizards have dark green blood. The bloodlike liquid flowing through the bodies of lobsters, crabs, snails, and shrimp is bluish green. The blood of some sea worms is pink or violet. Squids, octopuses, and horseshoe crabs have bright blue blood.
- When an elephant feels hot, it flaps its ears. That releases heat from the blood flowing through them. Then the blood travels to the rest of the elephant’s body and cools it off.
Looking for more Gross & Goofy Body facts? Check out my new book Pump It Up: The Secrets of the Heart and Blood. To find out more about the whole Grosss and Goofy Body series, read this very thorough review from School Library Journal.
In my household, next week is all about family and food, so I'm taking some time off to celebrate Thanksgiving. I have so much to be thankful for this year. I'll see you back here on November 29.