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Hybrid Sharks Discovery: Is There a Global Warming Connection?

In the movie "Austin Powers," the villain, Dr. Evil, demands that his henchmen find sharks with lasers on their heads in order to intimidate and kill his enemies.

Based on a news story out of Australia today, I suspect that if the same movie were to be made now, Mike Myers' Dr. Evil character would demand "hybrid sharks" with lasers on their heads instead. 

According to a wire report published by Discovery News, scientists working off the coast of Australia have discovered the world's first hybrid shark species, a mix of the local Australian blacktip shark with the global variety, the common blacktip.

The common blacktip shark. Credit: Wikimedia Commons.

The researchers found that the hybrid sharks are breeding, with several generations of offspring found among the sharks they performed genetic testing on. "It's very surprising because no one's ever seen shark hybrids before, this is not a common occurrence by any stretch of the imagination," said Jess Morgan of the University of Queensland. "This is evolution in action."

The story suggests that there may be a climate change connection, since the Australian blacktip shark has a more limited range compared to its more common cousin. As the story states:

"The Australian blacktip is slightly smaller than its common cousin and can only live in tropical waters, but its hybrid offspring have been found 2,000 kilometers (1,243 miles) down the coast, in cooler seas."

"If it hybridizes with the common species it can effectively shift its range further south into cooler waters, so the effect of this hybridizing is a range expansion," Morgan said. "It's enabled a species restricted to the tropics to move into temperate waters."

The story speculates that the hybridizing may be due to global warming-related changes in sea surface temperatures. However, that seems like a stretch, considering how little is known about sharks in general, as well as how they may respond to climate change. It's quite possible that the hybrid black tip sharks have existed for decades, and researchers only stumbled across them now.

It's also possible that hybridizing is an aspect of shark evolution that has simply evaded researchers, and that some hybrid species will have advantages over others as the climate changes. In other words,it may just be luck that a hybrid shark species like this one will fare better in a changing climate.