Questions for “Attack of the inner-cannibal mega-shark”

Megalodon shark illustration

Massive megalodons ruled the seas some 23 million to 2.5 million years ago. Why these giants got so big isn’t known. New research suggests it may be due to warm-bloodedness, lots of food — and cannibalization in the womb.

Warpaintcobra/iStock / Getty Images Plus

To accompany “Attack of the inner-cannibal mega-shark


Before Reading:

1. What are five of the biggest animals alive today? What are five of the biggest to have ever lived, past or present?

2. What factors do you think contribute to some species evolving to gigantic sizes? What factors do you think affected why other species have remained relatively small?

During Reading:

1.  Where and when did megalodon live? Name at least three of its features.

2.  What is intrauterine cannibalism?

3.  What is another name for mackerel sharks, and what are some examples of these sharks alive today? How many species of these have ever existed?

4.  What is endothermy and why do the researchers think megalodon was endothermic?

5.  Why do the researchers in Kenshu Shimada’s group think intrauterine cannibalism could have played a role in megalodon’s size and endothermy?

6.  Why does Stephen Godfrey claim that this reasoning does not “fully explain the unique super-gigantism of megalodon?”

After Reading:

1.  Sharks have an unusual reproductive cycle for a fish. They produce very few young, most of them born live. What advantage might this have over the way most other fish reproduce? What might the disadvantages be for the sharks’ style of reproduction?