A whale shark’s mouth is 1.5 metres wide and holds 3,000 teethDon’t worry too much just yet—as filter feeders whale sharks are certainly not out to get you—or really any other critter visible to us. They’re the largest fish on the planet, growing up to 18 metres in length and weighing in at 15 tonnes, but we still don’t know a whole lot about this gentle giant. Its 300 rows of teeth, totalling some 3,000 individual chompers, serve an unknown purpose.
The wobbegong shark latches on and won’t let goSimilar to a flatfish or ray, the wobbegong shark, or carpet shark, has a flat, streamline body well blended into the Pacific Ocean floor, where it hides awaiting overhead prey. The species' has a distinctive series of branched dermal lobes and nasal barbels that create a fringe covering the width of its jaw and snout. While it hides under reefs during the day, at night the shark perches on the reef’s surface, ready to lunge out at unsuspecting targets. The shark’s massive jaws and sharp teeth are deemed nearly impossible to escape from, so once the wobbegongs hooked it’s hooked. The odd name of the critter is thought to come from Aboriginal Australian, translating to ‘living rock.’
Most male courtship rituals involve bitingYes, you read that right—during mating male sharks get a grasp of females, allowing them to insert their sperm-filled ‘clasps’, modified pelvic fins, by biting them. We’ve all heard of love nips, and it’s not uncommon in the animal kingdom for things to get a little rough come copulation time, but sharks don’t mind a little pain apparently. Because they don’t have hands, claim researchers, sharks use their teeth to couple themselves with their partner. The female’s heads, pectoral fins, and gills are all open to love-attack. Once males have got a grip, the intertwined pair sinks to the ocean’s floor, the whole affair lasting several minutes. Sharks are known for their amazing healing capabilities, helping lovers to bounce back a bit quicker, but females may also have thicker skin than males to endure these events.
And you thought you were safe in freshwaterThough sharks and rays have certainly adapted to live in salty marine environments, some 43 species are thought to regularly venture into freshwater inlets and rivers. While most only spend a portion of their time in freshwater environments, bull and river sharks have been found living more or less full time inland. But how do they pull of this chemically extreme switch up? Turns out they pee—a lot. In Lake Nicaragua, one researcher working with bull sharks found the animals were taking in copious quantities of water and peeing out most as dilute urine, at a rate 20 times the norm of saltwater shark species. Being inland, a lot of freshwater sharks are today endangered, threatened by pollution, poor water quality, flow changes, and lessening food sources.
Some sharks can walkOk before you get too carried away with mental images here, none of the nine walking shark species discovered so far have legs, but they do use their pelvic fins as feet to walk along reefs and the sea floor from time to time. The most recent species, Hemiscyllium Halmahera, was found in 2013, like two-thirds of its kind living in Indonesian waters. These sharks are pretty small, growing only 27 inches or 70cm as adults and aren’t a threat to humans. Walking sharks are a fairly new scientific find, sometimes called epaulette sharks, for the military-esque pattern they don to blend into their coral homes.
Blue sharks eat until they puke…then go back for moreBlue sharks are beautiful but they don’t exactly have the best table manners. Researchers have observed groups of the sharks feasting on schools of mackerel and anchovies to the point of being sick—regurgitating only to return to feeding right after. Blue sharks are also indiscriminate eaters, chowing down on whatever’s around from fish to turtles, sea birds, squids and seals.
Orcas are a shark’s worst nightmareBeing top predators in their ecosystems, most shark species don’t spend a lot of time worrying about an attack, unless an orca or killer whale is around. Possibly the only water species capable of taking down a great white shark, orcas are a lot bigger and more powerful than their fish rivals. Though we’re unsure how often the pair tussle, a few years back an orca was documented off the coast of California ramming a great white at top speed before biting onto its head and flipping it over. The shocked shark went into a serotonin-induced trance of sorts, making things even easier for the whale who feasted on its prey shortly after.
Mako sharks are super speedstersWhile you may have never heard of it, the shortfin mako shark clocks in as the fastest shark species, pulling some 60mph sprints while hunting. Researchers think the species has evolved to become speed demons to keep up with their major prey species—tuna—using flexible scales on their gills and sides to reduce drag and make sharp turns. The species are also long distance champions on top of being short-burst experts; makos hold the long distance speed record for a marine species, travelling 2130km in 37 days.
The smallest shark could fit in your handAt just 15cm in length, the dwarf lantern shark holds the distinction of being the tiniest of all shark species. We’re still learning about the miniature predator, having only been spotted a few times in deep waters off the coast of northern South America, but the little critter has some pretty neat tricks. Like most lantern shark species the dwarf has photophores, light-emitting organs, lining their belly and fins, which glow in shallower waters helping it blend in with sunrays. A few years back researchers discovered a kin of the dwarf, the velvet belly lantern shark, uses their photophores for defence as well. Two spines on the species back fins light up in the dark depths of the water column, warning predators that swallowing them will be a prickly and painful affair.