Thresher sharks inhabit temperate coastal waters in the Atlantic and Pacific Oceans. They mainly feed on schools of smaller fish, such as sardines and anchovies, as well as squid and mollusks. The average lifespan of a thresher shark in the wild is 25 years.
1. Scientific & Common Names
4. Present Status
Scientific & Common Names
The scientific name of the common thresher shark is Alopias vulpinus. Common names for it include sea fox, fox shark and swiveltail. There are two other species of thresher sharks: Alopias pelagicus, or pelagic thresher, and Alopias superciliosus, or bigeye thresher.
Thresher sharks have a long upper tail fin, which is their most distinctive feature. They range from gray to dark brown in color, with white bellies and a green, blue or purple dorsal fin, depending on the species. Bigeye thresher sharks have enlarged eyes, while pelagic thresher sharks have longer snouts and narrower heads. Common thresher sharks are the largest species, with adults measuring between 5 and 19 feet long and weighing an average of 766 pounds.
Thresher sharks breed annually and do not appear to have a specific breeding season. The young develop in eggs that the mother carries inside her until they are ready to hatch. Females typically produce one or two offspring at a time and are not involved with caring for them once they are born. Thresher sharks grow slowly, with males reaching reproductive maturity when they are 9 or 10 years old and females maturing when they are 12 or 13 years old.
Thresher sharks often stay in shallow water during the night and spend their days in deeper water. They also migrate away from the equator in summer and toward it in winter. These sharks do not usually interact with other members of their species except to breed. They rely on their sense of smell, a lateral line that detects movement, and electromagnetic senses to find prey. Thresher sharks are shy and are not considered a threat to humans.
Thresher sharks are still present in much of their historic range, but their numbers are decreasing due to fishing. They are in high demand for their meat, fins and liver oil.
The common thresher shark, bigeye thresher shark and pelagic thresher shark are all listed as vulnerable. In addition to being targeted by unmanaged recreational and commercial fisheries, their populations are also declining due to a slow rate of recovery. Conservation efforts to protect these species include enforcing stricter fishing regulations and implementing bans on shark finning.