Why Hammerheads attack
Sharks attack and kill 10 humans per year, on average. Humans, in contrast, annually kill about 20 to 30 million sharks, according to the Florida Museum of Natural History's Department of Ichthyology. That shark death estimate, based on commercial and sportfishing landings, could even be conservative. It is therefore not too difficult to see which species poses the greater threat to the other. After 400 million years of shark evolution, we could potentially wipe out the world's sharks in a century's time.
The fact remains, however, that sharks can, and do, result in human deaths. Dogs and even traditionally mild-mannered animals like cows may kill people too, but the nature of shark attacks seems to fascinate and terrify us more. This year alone, two surfers from Mexico and two from California lost their lives after bleeding to death due to shark bites. The cluster of deaths puzzles researchers because, as shark numbers are declining overall, attacks seem to be holding steady, or are even rising, depending on the region.
The fact remains, however, that sharks can, and do, result in human deaths. Dogs and even traditionally mild-mannered animals like cows may kill people too, but the nature of shark attacks seems to fascinate and terrify us more. This year alone, two surfers from Mexico and two from California lost their lives after bleeding to death due to shark bites. The cluster of deaths puzzles researchers because, as shark numbers are declining overall, attacks seem to be holding steady, or are even rising, depending on the region.
Why Do Sharks Attack Humans?
After the recent deaths, some researchers are starting to wonder if certain sharks are developing a taste for humans. Jose Leonardo Castillo, chief shark investigator for Mexico's National Fishing Institute, recently announced that he and his colleagues are investigating this possibility, since criminal activity has resulted in bodies being dumped in the areas where the two surfers in Mexico died. It could be that, after repeatedly consuming other human flesh, one or more sharks could associate people with food.
Even if the food-human link is indirect, it likely explains most shark attacks in general. The National Oceanic and Atmospheric Administration (NOAA) explains that sharks do not normally hunt humans, but if they do attack, it is usually a case of mistaken identity. Assuming a large, predatory shark has not been exposed to human flesh before, it is probably used to biting into thick-tissued, fatty sea lions, seals and similar-bodied prey. Sometimes sharks will investigate potential food items by taking a taste. Unfortunately, given their many rows of sharp teeth, a few shark species can cause an individual to bleed to death after a single bite. The problem is compounded in lakes, rivers and estuaries, where freshwater sharks, such as bull sharks, often share water space with humans who are swimming, boating, fishing or engaged in some other form of recreation that might put them face to face with a shark
After the recent deaths, some researchers are starting to wonder if certain sharks are developing a taste for humans. Jose Leonardo Castillo, chief shark investigator for Mexico's National Fishing Institute, recently announced that he and his colleagues are investigating this possibility, since criminal activity has resulted in bodies being dumped in the areas where the two surfers in Mexico died. It could be that, after repeatedly consuming other human flesh, one or more sharks could associate people with food.
Even if the food-human link is indirect, it likely explains most shark attacks in general. The National Oceanic and Atmospheric Administration (NOAA) explains that sharks do not normally hunt humans, but if they do attack, it is usually a case of mistaken identity. Assuming a large, predatory shark has not been exposed to human flesh before, it is probably used to biting into thick-tissued, fatty sea lions, seals and similar-bodied prey. Sometimes sharks will investigate potential food items by taking a taste. Unfortunately, given their many rows of sharp teeth, a few shark species can cause an individual to bleed to death after a single bite. The problem is compounded in lakes, rivers and estuaries, where freshwater sharks, such as bull sharks, often share water space with humans who are swimming, boating, fishing or engaged in some other form of recreation that might put them face to face with a shark
The map shows southern Florida and the Bahamas where most Hammerheads school and feed of the beaches of Florida, don't worry they only have a taste for fish.
Hammerhead habitats
Circumtropical in distribution, the great hammerhead is found in coastal warm temperate and tropical waters within 40°N - 37°S latitude. In the western Atlantic Ocean, it ranges from North Carolina (US) south to Uruguay, including the Gulf of Mexico and Caribbean regions, while in the eastern Atlantic Ocean, this species ranges from Morocco to Senegal, including the Mediterranean Sea. Distribution of the great hammerhead includes the Indian Ocean and the Indo-Pacific region from Ryukyu Island to New Caledonia and French Polynesia. The eastern Pacific range is from southern Baja, California (US) through Mexico, south to Peru. The great hammerhead is considered a highly migratory species within Annex I of the 1982 Convention on the Law of the Sea. This large coastal/semi-oceanic shark is found far offshore to depths of 300 m as well as in shallow coastal areas such as over continental shelves and lagoons. The great hammerhead migrates seasonally, moving poleward to cooler waters during the summer months.
Fast Facts
1. The Great Hammerhead shark habitat, the Great hammerhead is found far offshore at depths of 300 ft at some points, the great hammerhead also is shallow coastal waters such as lagoons the shark migrates seasonally to warmer places in the winter and cooler places in the summer, the great hammerhead is usually found in Florida and the Gulf of Mexico.
2. The head of the great hammerhead is nearly straight with a shallow notch in the center. The first dorsal fin is very tall with a pointed tip. The anal fin is deeply notched.
3. The teeth of the great hammerhead are triangular and strongly separated, but increasingly oblique toward the corners of the mouth. There are 17 teeth on either side of the 2-3 teeth at the symphysis in the upper jaw.
4. At the largest of the hammerheads, the great hammerhead averages at over 500 lb. The world record hammerhead was caught off of Sarasota, Florida weighing 991 lb. The largest recorded length of the great hammerhead is 20 feet. The life span of the shark is between 20-30 years.
5. The Great Hammerhead
Taxonomy
Kingdom --- Animalia
Phylum --- Chordata
Class --- Chondrichthyes
Order --- Carcharhiniformes
Family --- Sphyrnidae
Genus --- Sphyrna
Species --- Mokarran
6. Hammerhead sharks eat squid, stingrays, octopus, fish, crustaceans, crabs, and sometimes other hammerhead sharks.
7. Hammerhead sharks have small mouths so they can only fit a small amount of food in their mouth at once, compared to other sharks who have bigger mouths and can fit more food in their mouths.
8. Hammerhead sharks mainly eat stingrays because it is considered their favorite food, out of all the other foods.
9. A hammerhead shark usually hunts for their food at night,And they hunt for their food at the bottom of the ocean, they hunt for stingrays that hide under the sand on the seafloor.
10. Hammerhead sharks hunt for their food twice a day around dawn and dusk, and they pick the food of their choice.
11. Hammerhead sharks often hunt at night. Compared to other predators, they have very small mouths. Because of their small mouths, they usually obtain their food from the bottom. They have a preferred prey of rays, shrimps, squids, small fish, and even other shark species.
12. Hammerheads have a Heightened electroreception sense which means they detect natural electric stimuli. Because of this ability, they hunt animals that have give off electric stimuli. The reason behind this heightened sense is because of their hammer shaped head.
13. Their wide-set eyes give them a better visual range than most other sharks. Because their eyes are spread apart their vision is enhanced allowing them to sight their prey more easily than other species.
14. Hammerheads use their head to pin stingrays meanwhile their mouth which is located below their head will eat the ray. Because of this adaptation they can scoop up animals that live on the floor.
15. The Hammerhead’s body allows it to make sharp turns that are very sudden. It’s head provides the balance to turn suddenly and sharp. The shark’s body seems to be specifically made to turn like this.
16. Hammerhead sharks move to warmer waters. The only causes are weather and breeding. Winters can get very cold so they migrate to places that are warmer like Florida. Also it is natural for them to migrate to go south to breed their young.
17. Hammerheads are semi- oceanic which means they can live in freshwater and saltwater.
18. Hammerhead sharks are found offshore. Hammerheads are mainly found around Florida, The Bahamas, and along the Caribbean Islands.
19. Hammerheads migrate seasonally. That means during the winter, they migrate because of lack of warm temperatures. Birds do the same thing. When winter arrives, they migrate east to where it is warmer.
20. Hammerheads live in coastal areas such as Florida or the Bahamas. Both are warm all year so they are a perfect locations for hammerhead sharks.
21. The smooth hammerhead, scalloped hammerhead, and great hammerhead are of the 10 known species of sharks that are known to be aggressive and dangerously attack humans.
22. Over the past five years an average of 4.2 shark attacks have taken place each year worldwide. From 2013 a number of 33 hammerhead shark attacks have occurred, non fatal, meaning and injury resulting in severe exposure to an external force or substance.
23. There has been 17 non fatal unprovoked hammerhead attacks , and 0 fatal unprovoked attacks. This is 17 out of 668 other shark attacks from other species of sharks.
24. The U.S average of shark attacks each year is only 19. However, in the coastal U. S states alone, there has been more than 37 kills on people each year. Since 1959 Florida has had more shark attacks than lightning fatalities.
25. Although dangerous, the hammerhead rarely attacks humans. It sometimes behaves inquisitively towards divers and should be treated with respect. We kill about 100 million sharks a year. Compared to the amount of kills on humans that is not a lot.
Kinds of Hammerhead Sharks
Schools of Hammerheads!
Sources
Bester, Cathleen. Sphyrna mokarran. University of Florida. Web. 6 Apr. 2016.
https://www.flmnh.ufl.edu/fish/discover/species-profiles/sphyrna-mokarran
Fitzgerald, Timothy. October 28, 2004. Web. 6, April, 2016. http://www.hawaii.edu/himb/sharklab/research/kajiura.html
"NationalGeographicSociety Hammerhead Shark." Web. 5, April, 2016.
http://kids.nationalgeographic.com/animals/hammerhead-shark/#hammerhead-shark-swimming.jpg
Rogers, Mike. "From Hammerhead Shark to Types of Sharks." Web. 6, April, 2016. http://www.sharksider.com/hammerhead-shark/
“Scalloped Hammerhead Sharks.” 6 April 2016.
http://www.montereybayaquarium.org/animal-guide/fishes/scalloped-hammerhead-shark
https://www.flmnh.ufl.edu/fish/discover/species-profiles/sphyrna-mokarran
Fitzgerald, Timothy. October 28, 2004. Web. 6, April, 2016. http://www.hawaii.edu/himb/sharklab/research/kajiura.html
"NationalGeographicSociety Hammerhead Shark." Web. 5, April, 2016.
http://kids.nationalgeographic.com/animals/hammerhead-shark/#hammerhead-shark-swimming.jpg
Rogers, Mike. "From Hammerhead Shark to Types of Sharks." Web. 6, April, 2016. http://www.sharksider.com/hammerhead-shark/
“Scalloped Hammerhead Sharks.” 6 April 2016.
http://www.montereybayaquarium.org/animal-guide/fishes/scalloped-hammerhead-shark
Creators of this page
Justin McNamara
Colleen Fitzmaurice
Brendan Geary
Braeden Murphy
Melissa Gulinello
Colleen Fitzmaurice
Brendan Geary
Braeden Murphy
Melissa Gulinello