Longfin Mako Sharks are slender, spindle-shaped sharks with conical snouts. The word “Mako” comes from the Māori language meaning either the shark or a shark tooth. It originated in a dialectal variation as it is similar to the common words for shark in a number of Polynesian languages – “makō” in the Kāi Tahu Māori dialect, “mangō” in other Māori dialects, “mago” in Samoan, “ma’o” in Tahitian and “mano” in Hawaiian. Their teeth are moderately long, smooth-edged, without basal cusplets. Their gill slits are long, extending partially onto the top of their heads. They have broad-tipped pectoral fins that are as long or longer than their head (measured by the straight-line distance from tip of snout to top of 5th gill slit). Their first dorsal fin origin is behind the rear tip of their pectoral fins. Their second dorsal and anal fins are small with pivoting bases. They have strong keels on their caudal peduncle and their caudal (tail) fin is lunate (sickle-shaped). Longfin Makos are dark blue to bluish black above, fading to bluish grey on their flanks and the under-surface of their snouts. The area around their mouth is a dusky or bluish black. Longfin Mako Shark pups measure 97-125 centimeters long and about 12 kilograms at birth. As adults, most measure about 2.2 meters long and weigh 70 kilograms. Their maximum known length is 4.3 meters, based on a female taken 24 kilometers off Pompano Beach, Florida in February 1984.
Formally described only in 1966, Longfin Mako Sharks are one of the least known lamnids. They are also the second-largest member of its family, after the Great White Shark. Their long, broad pectoral fins suggest that this species is slower and less active than their cousin, the Shortfin Mako Shark. Longfin Mako Sharks have the same heat-retaining circulatory systems as other lamnids, although this species is not warm-bodied. Their large eyes indicate that they are a deep-dwelling species. Long-line catches off northern Cuba are most commonly brought up from depths of 110 to 220 meters. Longfin Mako Sharks are found in tropical to warm temperate seas, but records are spotty due in part to their confusion with their relative, the Shortfin Mako Shark. They are fairly common in the western Atlantic, Gulf Stream waters, northern Cuba to southeastern Florida and possibly in the central Pacific and north of Hawaii. Longfin Mako Sharks primarily inhabit the upper mesopelagic during the day, venturing into the epipelagic at night. They likely feed on pelagic squids and schooling fishes. Longfin Mako Sharks are ovoviviparous at the stages of development with an average litter size of 2-8 pups. Males mature at a length of about 2.0 meters, females at about 2.5 meters; there are no data on age at maturity or longevity for either sex.