They are easily recognized because the upper lobe of the tail is usually as long as the rest of the body (appreciably longer in A. vulpinus). The caudal peduncle lacks keels, the teeth are small and pointed with broad bases, and the skin is smoother than that of most other sharks. The longtail thresher and the palegic thresher have moderate sized eyes (1.2-1.5 percent of the total body length). The first dorsal fin is located almost squarely in the middle of the back, well forward of the origin of the pelvic fins. The Atlantic and Pacific bigeye threshers have much larger eyes (2.8-4.1 percent of the total body length) and the rear margin of the dorsal fin is located at least as far back as the origin of the pelvic fins. The belly and lower flanks of thresher sharks may be mottled.

Threshers are a solitary species that is not uncommon for them to congregate when large schools of bait fish are available and occasionally hunt in pairs. Their diet is known to include mackerel, menhaden, needlefish and bluefish. Typically a thresher will slap the water with its tail to herd bait fish into a mass then use its tail to stun the fish. An angler may see his bait fish slapped out of the water then swallowed as it settles back in again, which is why threshers are often hooked in the tail. They are very active fighters when hooked and have been known to leap clear out of the water. Fishing methods include trolling in marlin fashion or deep trolling or drifting, depending on the species being caught. Whole baits, strip baits, live yellowtail, snapper, or mullet may be used as well as feathers, or other baits or lures which are generally used for marlin or tuna.

They are ovoviviparous and give birth to 2 to 4 large babies, about 5 ft. (1.5 m) long. There is no record of a thresher shark ever attacking a person, but they have attacked boats. The flesh is of good quality but is more often used as bait or chum at catch other sharks than as food.