# A Secret about Seahorses

Most animal tails are round: if you looked a dog’s tail head-on from the tip, you’d see a circle (its “cross-section”). But the seahorse’s tail is square. It’s actually a stack of 36 square plates; each square is made up of 4 L-shaped bones. Scientists figured out that a square tail is actually stronger and takes less energy to move than a round one. Scientists think this could help them build stronger robots, in case those robots ever need to grab some seaweed for dinner.

Wee ones: How many sides does a square have?

Little kids: Seahorses swim really slowly, only about 5 feet per hour. Take 5 slow steps and count them starting with the number 4. What numbers do you say?  Bonus: Seahorses can be as long as 14 inches. If your pet seahorse is just 1 inch shorter than that, how long is it? How does that compare to your hand?

Big kids: A mama seahorse can lay up to 1,500 eggs at a time. If she’s laid 1,100 so far, how many more could she lay?  Bonus: If every 4th tail plate of the 36 (starting with the 4th) has a pink L in it, and every 6th plate starting with the 6th has a blue one, what’s the first plate that has both?

Wee ones: 4 sides.

Little kids: 4, 5, 6, 7, 8.  Bonus: 13 inches, which is a lot longer than your hand!

Big kids: 400 more eggs.  Bonus: The 12th plate, since it’s divisible by both 4 and 6.