There are more than 440 known species of sharks across all seas on earth. The sharks are carnivores supported by their robust jaws and sharp replaceable teeth, though a few species are plankton feeders. Reproduction occurs through laying eggs which hatch into pups though some species give birth through a process called viviparity, especially in dangerous ecosystems. Scientifically classified as Chondrichthyes, sharks are divided as outlined below.
Subspecies of Sharks
The numerous species can be broadly categorized into 8 subgroups.
- Carcharhiniforms, also known as ground sharks, include the Caribbean Reef Shark, Black Tail Reef Shark, Grey Reef Shark, Hound Shark, Catshark and the Blue Tiger Shark. They are identified by their long snout and eye membrane which covers the eyes when hunting.
- Heterodontiformes include Bullhead Sharks and Horn Sharks, and are known for their dorsal fin spines.
- Hexanchiformes, which include Cow Sharks and Frilled Sharks, are characterized by having one dorsal fin and 6 or 7 gill slits.
- Lamniformes, such as Mackerel Sharks, Goblin Sharks, Megamouth Sharks, and Basking Sharks, have huge jaws and reproduce by laying eggs.
- Oroctolobiformes, which include Carpet Sharks, Nurse Sharks, Wobbegong Sharks, Zebra Sharks, and the Whale Shark, have eyes set far behind a small mouth.
- Pristiophoriformes, such as Shawsharks, are known for their saw-like teeth located in the snout.
- Squaliformes, including Dogfish Sharks and Rough Sharks, lack the anal fin but can swim in the high seas due to their elongated dorsal fins.
- Squatiniformes, such as Angel Sharks, are known for their flattened bodies.
Large Shark Species
Whale sharks, at 65 feet and a weight of 75,000 pounds, are the largest of them all. They are extremely huge. In comparison, Basking Sharks can be at a maximum of 40 feet long. Tiger Sharks grow up to 18 feet and can weigh 2000 pounds. Bull Sharks and Great White Sharks are known to attack human beings. They are usually between 12 and 20 feet long and naturally curious. Thresher Sharks are characterized by huge eyes and a tiny mouth. The Oceanic Whitetip species like the deep open sea a long distance from the land. The Hammerhead species are called so due to the shapes of their heads. The 14 feet long Sand Tiger species has a flat snout and likes burying itself in the sand. Most of the large species live on the warm sides of the Atlantic, Pacific and Indian Ocean.
Small Shark Species
The smallest species are led by the Dwarf Lantern Shark, which measures below 8 inches in length. The Brown-Banded species is also a comparatively small species whose female can keep sperm for up to 45 months to fertilize themselves on an as-needed basis. The Blacktip Reef species can only grow to 6 feet, whereas the Lemon Shark species, with their yellow-brown skin, grows to eleven feet. They are found on the shallow edges of the sea and are prone to predators.
Characteristics of Shark Species
A few species have been known to attack people. These include the Great White Shark, which is the most aggressive species, along with the Bull Shark and the Tiger Shark. The friendliest species are the Nurse Shark, Leopard Shark, Angel Shark, and the Caribbean Reef Shark. The Greenland Shark species is the slowest in swimming but can live up to 272 years.