A Tale of Two Sharks

Scientists have been looking for answers to questions for hundreds, nay thousands, of years now. But, as is the nature of scientific inquiry, each question answered brings forth two new questions, like the mythological hydra. The sea is one of the most mysterious places on earth, what with its glassy surface hiding beasts, plants and geological formations the likes of which we have never seen. Recently, scientists dove into the deep and found a new hybrid shark, and like with other scientific discoveries, those sharks brought with them more questions.

Australia is one of the most beautiful and exciting places to work, well, if you’re into creepy-crawlies, beasties, and things that go bump in the day or night. There are a whopping 180 species of sharks lurking in its waters, and thanks to the work of Jess Morgan and Colin Simpfendorfer, we now know that these species are changing in new and unexpected ways: two species have started to mate with each other, creating a new, hybrid shark.

A blacktip shark (Carcharhinus limbatus) in UShaka Sea World; created and added to wikicommons by Amanda44.

Furthermore, these hybrid sharks can reproduce! It’s rare that two species can hybridize with each other, and it is even more rare that the offspring can reproduce as well. Think about mules, the offspring of a female horse and a male donkey: a mule is a hybrid, but it cannot reproduce. This new shark can do it all. And, it’s the first time that such a hybrid shark has been documented. Well, there’s a first for everything, and this is one first that’s reminiscent of science fiction horror movies.

The reality isn’t quite that sensationalistic, but it’s still pretty big: while the scientists don’t know why these sharks are hybridizing, one theory suggests that this is how they’re responding to global warming. The two sharks in question are the common blacktip, a shark with a large range and tolerance of cooler waters, and the Australian blacktip, a slightly smaller shark with a limited range (right around Australia, as you might guess), and a preference for tropical waters. The hybrids have a larger range than the Australian blacktip, and this larger range may be beneficial for the sharks when they’re faced with a changing climate.

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