The Price of a Warm Body: teacher key

Mako Sharks, grade 9 edition, written for 9th grade. A warm body helps a mako cruise far and fast, but it costs a lot of energy. See what a 2015 study and a 2023 study found.

Read the book. Print this page for the key.

Questions and answers

1. What did the 2015 study find about fishes with warm red muscle?
   • Their cruising speeds and migration ranges were 2 to 3 times greater (answer)
   • They were smaller
   • They lived on land
2. What does warm red muscle cost, according to the study?
   • Nothing
   • Twice the cost of transport (answer)
   • Half the cost of transport
3. How did the 2023 study measure speed?
   • With a stopwatch on a boat
   • With a radar gun
   • With tags worn by two free-swimming makos (answer)
4. Why might a warm body be worth its cost?
   • Faster cruising helps meet more prey and allows larger migrations (answer)
   • It makes fish glow
   • It keeps the fish dry
5. What did the New Zealand study challenge?
   • The age of makos
   • The view that makos are nomadic wanderers (answer)
   • The size of the ocean
6. How long ago did the sharks and tunas groups diverge?
   • About 450 years ago
   • Last year
   • More than 450 million years ago (answer)

Words

• diverged: split apart
• migration: long trip
• cruising: steady swimming
• segregation: keeping apart