Welcome to the terrific world of underwater creatures . From seals to sharks , and whales to whale shark , we break down just what is swimming beneath the ocean waves and where they fit in with those animals that are much happier gallivanting about on land .
Why are sharks not mammals?
To jump with , let ’s address a uncouth misapprehension . shark are not mammals , they are fish .
In taxonomic term there are two broad course of instruction of fish . There’sOsteichthyesor the bony fish , which includes fish metal money likegoldfish , trout , and piranhas . The second big class isChondrichthyes . These are have intercourse as the cartilaginous fish ; they have jaw and skeletons made of cartilage not osseous tissue . This is the class that all sharks belong to , andAustralian Museumhas a helpful diagram that put down it all out .
There are around 500 species of shark swim in the ocean and occasionally thelakesof the world , fit in to theInternational Fund For Animal Welfare .
Ocean mammals
All whale , dolphins , porpoises , and seals are marine mammals . The first three belong to the infraorder ofCetacea , intend that they are all more or less closely touch on . By contrast , seal of approval belong to the infraorderPinnipedia , which also includes ocean Lion andwalruses .
Whale sharks
Zoologists can be quite puzzling when it get tonaming animate being . The whale shark is a premier exercise of this . Whale sharks ( Rhincodon typus ) are not whale and therefore not mammals , but are sharks and by extension fish . Theycan extend to lengths of around 12 meters ( 40 feet ) and librate as much as 20.6 piles according toNational Geographic . In fact they are the world’slargest Pisces mintage , beating great white sharks and basking shark to the title .
The humankind ’s largest fauna , however , is ablue whale(Balaenoptera musculus ) , which can be as long as 24 meters ( 78 feet ) and weigh 150 short ton . Since we now get laid that whales are mammals , they ’re also the earth ’s largest mammalian .
The key differences
The main difference that can serve you tell if an animal is a Pisces the Fishes or a mammal are quite obvious once you know what to search for .
The first has to do with ventilation . whale breathe oxygen through theblow holeson their heads , which means that they must go bad the aerofoil of the pee to breathe in the atomic number 8 before closing the venthole and diving beneath the surface . They have lungs that the aviation is passed into in the same means as a man . When whales get stranded , because they can still respire , they can often berescuedand refloated back out to ocean .
Sharks do not have blow trap and do not suspire air like a whale . Insteadthey have gillsthat filter atomic number 8 from the brine and take wastefulness carbon dioxide from the roue back into the ocean . They do not have lungs . Typically , if a large shark were to be stranded out of the water it would not survive , because they can not take a breath directly from the air ; however , some coinage can survive for longer without water , like the"walking " shark .
The other key difference is in reproduction . Whales , cachet , and dolphins all reproduce by internal fecundation and give birth tolive youngthat they then care for , feed in them Milk River that is produced in the mother ’s body . shark , however , depending on species have a whole range of reproductive option , including live young and laying orchis , but never flow their young Milk River .
Another fun difference between sharks and mammals is that while shark never have hair , whalesoccasionally do .
