Sharks Archives - The Hamny

Sharks are one of the largest fish on earth and there is a good reason why they are often referred to as ‘living fossils’. Some species can live for so long that you would think it’s a lie. And yes, Sharks are fish and not mammals. Summary: How Long Do Sharks Live? Sharks have been known to have the longest lifespan among fish. On average, most sharks live for 20 to 30 yearsThe Greenland Shark species have the longest lifespan. They can live for 200 to 500 years. Sharks live more in the wild than when in captivity An Overview on Sharks Before we have a look at their lifespan, here is an overview of Sharks. Sharks are categorized under a group of fish known “Elasmobranchii.” All species under this category are characterized by a cartilaginous skeleton, pectoral fins fused to the head, and five to seven-gill slits attached to their heads. Sharks have been known to inhabit the earth for a very long period. Biologists believe that they have been living on the Earth from almost 400 million years ago. You may be shocked to know that the Sea Dogs were even present before the dinosaur era. This means they were here long before the appearance of dinosaurs on earth. Sharks have undergone tremendous evolution over the years. Currently, there are almost 500 distinct species of sharks. They all vary in diet, size, color, habitats and even have distinct behaviors. Sharks live in water and use their gills to breathe underwater. The gills filter the oxygen present in the water. Typically sharks do not have normal bones. This is because they are made of cartilaginous tissues which are lighter than the bones of other animals. Other fish which also share this tissue are the sawfish, rays, and skates. The cartilage that sharks are made of is the same that makes human ears and the nose. What an interesting fact to know! How Long Do Sharks Live? Most sharks live for 20 to 30 years. Some live much longer like the Greenland Shark that lives for up to 500 years. Scientists usually count the number of growth rings which develop on sharks’ vertebrae. Each ring would stand for one year and so on. The life expectancy of sharks in captivity is way shorter than those in the wild. Due to their migratory and feeding patterns, it is a challenge for scientists to determine the exact age of sharks. Nevertheless, their lifespan varies quite a lot depending on the species. Let us have a look at the lifespan of the following 4 shark species: 1. How Long Do Great White Shark Live? The Great White Sharks have a lifespan of 30 to 100 years. They are large and can be found in major oceans. Their name is derived from the color of their belly which is white. The great white shark is able to grow to over 20 feet long with a weight of over 2.5 tons. No wonder they have the name great! They have an excellent sense of smell, doubled by a set of sharp teeth perfect for hunting and tearing their prey. Great White sharks are predators. They are known for sky hopping, that is to lift its head above the water to locate prey. [1] Here is an interesting documentary on sharks lifespans. 2. How Long Do Dogfish Sharks Live? Spiny Dogfish Sharks can live for more than 100 years. Spiny dogfish females grow larger and older than their male counterparts. At 9.1 years of age, the females will have matured 50 percent while the males reach 50 percent maturity at 7.5 years. Mating for the spiny dogfish involves internal fertilization. This is as is the case with all elasmobranchs that is sharks, skates, and rays. It occurs in offshore areas during the winter and fall seasons. The spiny dogfish is an ovoviviparous species. They have an 18 to 22-month gestation period and bear 1 to 15 pups. The pups can live for as long as 25 to 30 years. While the female is still pregnant, the next batch of eggs starts forming so she can become pregnant again shortly after giving birth. The name dogfish was adapted by fishermen who noticed their behavior of chasing smaller schools of fish as packs. This is because this species normally is made of large schools of hundreds to thousands of sharks composed of the same size and sex. 3. How Long Do Blue Sharks Live? The average lifespan for a blue shark is between 15 to 20 years but some may live longer than this. This shark is characterized by a slender body and the rich indigo coloring that gets it the name. The distinctive color of this species allows it to camouflage easily and quickly in the blue ocean. Blue sharks migrate a lot but they normally settle for a short while to mate in shallower waters. The female blue shark normally carries the embryo for 9-12 months before giving birth. The blue shark is unique from other sea creatures. This is because they, much like human beings, carry and nurture the embryo until it’s grown. The female blue shark can produce a litter of 30 and 80 pups in a single reproduction cycle. Male blue sharks mature earlier at the ages between four and six. Females on the other hand mature later between ages five and seven. Blue sharks usually feast on a diet of pelagic fish such as cod, helling, tuna, swordfish, squid, and sometimes seals. 4. How Long Do Silky Sharks Live? On average Silky Sharks live for 23 to 25 years. They live longer in the wild compared to when in captive. This species gets its name from the silky feel of its skin. Their skin is covered with dermal denticles. During their life cycle, they transition between different habitats. The young ones live in nursery grounds and as they grow older migrate to deeper waters. Silky sharks give birth to their young as females have oviducts and uteri. Males release pheromones and they usually mate with multiple females per breeding season. They are known to be solitary in nature generally but sometimes may travel in groups. Silky sharks are active both during the day and night. This species is known to be a top predator feeding on many types of fish and also hosts several parasites such as tapeworms and isopods. Conclusion There are a variety of shark species including the sandbar and brown sharks which have a life expectancy of 20 to 30 years and hammerhead sharks can live for 20 to 30 years as well. Currently, the lifespan of some shark species is shortening. It is believed to be due to sharks being confined hence reducing their lifespan to around 9 years. For us to protect the sharks we should let them live in the wild. In fact holding sharks captive is quite dangerous as they have acute senses such as smell and sight and are easily irritable. 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