Where do sharks go on vacation?

Fin-land, ba dum tsh

I know it's been a while since my last post, somehow time has gone faster lately. But now I'm here and I will continue my sharks tale.

This shark is known by many names. Zambezi Shark, Nicaragua Shark, and Ganges River Shark are some of them. Mainly based of the location where they hang out. The name we all know it by is however the bull shark. Most people would also say it's one of the most dangerous shark species, maybe even more so then the great white. I've also read that it's pretty much the garbage bin of the sea as it likes to try a bite of everything, might be where the rumour of being the most aggressive shark comes from as well.

Picture taken from Wikipedia

As in many cases of nature the female is bigger, range between 180cm to 230cm but have in extreme cases been recorded to be over 3 meters. While the male ranges between 157cm to 226cm. Despite their size they're surprisingly agile as they can reach the speed of 11 mph / 17 kmh. What doesn't help us humans either is that their eye sight is apparently awful. However their very recognisable snout have an incredible sense of smell which comes in handy when they're out looking for prey. As their snout suggests, bumping is the second best to check and I'm afraid these bullies don't have Wikipedia to check what's edible or not so to be 100% sure a quick bite will tell. Good for them, unfortunate for us, as their bite is one of the strongest weight for weight bite in the cartilaginous fish family.

But please remember that these fantastic terrifying creatures don't want to eat you but as they're opportunists and hungry you might (with their terrible eyesight) be mistaken for a tasty snack as a seal. 

It's clear that the more humans in the water the more conflicts. However would you compare the number between how many sharks deaths we have caused versus the fatalities they've caused, we look like savages. Which I definitely think we are, we chose to swim in the sea, they can't choose to live on land and still we blame them. We're on their property, their only property. There were 4 fatal shark "attacks" 2018  and I can't even imagine how many fatal human attacks we amounted to in 2018.

Anyway on we go. Bull sharks have a very varied diet, which depends on their location. Because these sharks can function and inhabit both freshwater and salt water. From what we've discovered there's 43 species of shark who can do this, 43 might sound like a lot but it's only a 10th of all the shark species.

So what's the difference between the two? Well basically the bull sharks can regulate their osmosis as they travel from seawater to freshwater and vice verse. As they gradually move from the sea in to freshwater their kidneys starts to remove less salt and more urea from the bloodstream through urination. As the bull sharks skin detects the salinity level changing the rectal gland will restrict how much of the urea it will release which will then keep the water concentration in the sharks body balanced. How cool? But it makes me wonder why aren't all sharks capable of this? I've been searching the web and on Wikipedia is says this:

"Evolutionary assumptions can be made to help explain this sort of evolutionary disconnect, one being that the bull shark encountered a population bottleneck that occurred during the last ice age. This bottleneck may have separated the bull shark from the rest of the Elasmobranchii subclass and favoured the genes for an osmo-regulatory system."

So I think we should consider ourselves lucky that we don't have all the 440 species swimming up the rivers and lakes. Would be very crowded especially with the crocodiles as well and can you imagine a hippopotamus sharing their waters with even more sharks? Nope they would not be happy, and you always want to keep a hippo happy and to be fare I wouldn't anger the crocodile either. 

Although with the environmental challenges we face today I can't help but wondering if in the future we will see more sharks in freshwater? Or just no sharks at all?

As once said by our beloved David Attenborough:

"The question is, are we happy to suppose that our grandchildren may never be able to see an elephant except in a picture book?” 

Except that the elephant is now the shark. What do you think?