The hammerhead shark is probably the most recognizable fish in the ocean with many of its traits such as facial characteristics, size and behavior quite unique. Hammerhead sharks, "Sphyrna sphyrnidae," are aggressive predators found in warm waters along coastlines and continental shelves. This protected species is often caught by fisherman but usually released back into the water. Only three of the nine species of hammerheads are dangerous to humans: great, scalloped, and smooth hammerheads. The others are called the whitefin, winghead, scoopedhead, bonnethead, smalleye, and the scalloped bonnethead.
Reproduction for hammerhead sharks happens about once a year with each liter containing 20-40 pups. Once the pups are born the parents do not stay with them and leave them on their own. In May 2007 scientists discovered that these sharks can reproduce asexually through a rare method known as parthenogenesis. At first people were skeptical but a pup lacking any paternal DNA has proved the theories correct. This is the first type shark that to our knowledge does this.
Hammerhead sharks are aggressive predators with a good sense of smell to help them locate their prey. Their main diet includes fish, cephalopods, other sharks and crustaceans. There favorite, as it seems, is stingrays. They use their "hammer" to pin the ray down for the kill; they then take bites of the rays' wings. Hammerhead sharks have also been known to be cannibalistic.
The hammerheads swim in relatively warm areas and and particularly warm water along coastlines. They live over the continental shelves and down to depths of 260 feet. They can be found in tropical and sub tropical waters worldwide. The hammerheads migrate to cooler water during the summer.
THE KNOWN SPECIES
Physical appearances of hammerhead known species range in length from three to twenty feet. Every species has a projection on each side that gives it's head and face a resemblance to a flattened hammer. At one point the distinctive shape of the hammerhead was thought to help them get food by easier maneuvering through the water. However, it was found that the design of the vertebrae helps more than the shape of their head.
The shape of their heads has contributed to the hammerhead's sense of smell by allowing them longer nasal tracks and also by making it more necessesary for them to rely on smell. Because hammerheads have small mouths they have to do a lot of bottom-hunting. The shape of their head and their increased sense of smell helps them with that.
While the hammerhead shark is very well recognized, there is also a lot that is surprising about the shark and a lot that is still being learned and that scientists don't think they understand very well.
Examples, there migration behavior is typical and well known but not always explained. They are also typically seen in groups, as they are known to form schools during the day, sometimes in groups of over 100. In the evening, they become solitary hunters. Sometimes scientists learn things that surprise them. Hammerheads are also strangely one of the few creatures in the animal kingdom to get a tan by exposure to the sun. The only others are pigs and humans. The more things like this they learn and become able to explain the more they understand and are able to help the species.