Some fish warm their bodies, and a shortfin mako is one of them. So a mako's body runs warmer than the sea it swims in. It keeps its body warmer than the water around it, because a web of blood vessels holds in the heat. A mako's warm body is 6 to 8 degrees Celsius above the water temperature. This ability is old and it arose more than once. Warm-bodied sharks and tunas evolved it separately, and their two groups diverged more than 450 million years ago. Their common ancestor was probably cold-blooded. The shortfin mako is one of four shark species in a 2015 study that warm their bodies; the others are the salmon, porbeagle and white shark.

Scientists asked what a warm body is good for. In that 2015 study, the cruising speeds and yearly migration ranges of fishes with warm red muscle were 2 to 3 times greater than for fishes without it. In other words, the warm fishes cruised faster and travelled farther each year, and the values were similar to those of penguins and marine mammals. There is a price, however: the study estimated that the cost of transport for these fishes is twice that of fishes without warm muscle. The researchers suggested that the high energy cost is paid back by faster cruising, which raises how often a fish meets prey, and it allows larger yearly migrations.

In 2023, scientists measured what two makos actually did. Tags worn by two free-swimming makos measured their swimming speed directly. The two makos cruised at an average speed of 0.90 metres per second. The study found that makos generally cruise at speeds similar to other warm-bodied fish, and faster than sharks that do not warm their bodies. The fastest burst the tags recorded was 5.02 metres per second, from a female mako 2 metres long. The tags also recorded a burst that lasted 14 seconds, at an average speed of 2.38 metres per second. At the cruising speed, the tails beat about once every two seconds, a mean tail-beat frequency of 0.51 Hz. At the fastest burst it was 3.65 Hz.

A mako's senses and teeth are tools for hunting. A mako's upper teeth tend to be broader than its lower teeth, and the first two lower teeth next to the jaw's midline are longer and more slender. Makos have excellent eyesight, because millions of rod cells and a layer that reflects light back into the retina give them keen vision in low light, and they also have a well-developed sense of smell. They sense water movement with a lateral line, and they have electric sense organs called ampullae of Lorenzini that can detect prey.

Makos do not all live alike. Adult male and female makos are seldom found together in some areas, which scientists call sexual segregation. In a New Zealand study, tagged makos spent a median of 77 percent of their time in New Zealand waters, which challenged the view that makos are nomadic wanderers. Even so, makos can travel a long way: in the western Gulf of Mexico, makos were tracked for 10 to 887 days, and two mature males made seasonal migrations of about 2,500 kilometres. Makos tagged off California stayed on the eastern side of the Pacific, which suggests they do not mix much with makos in other parts of the Pacific.

Words to know

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