Here's why:
* Abundance: Tuna are common in the open ocean, where mako sharks live.
* High energy: Tuna is a rich source of energy, which is essential for the mako's high-energy lifestyle.
* Speed: Tuna's speed makes them challenging prey, which appeals to the mako's hunting instinct.
Of course, mako sharks are opportunistic feeders and will also eat other fish, squid, and even smaller sharks.