In 2012, researchers discovered a previously unknown type of hybrid shark along Australia’s eastern coastline. While the term “hybrid shark” might sound like something out of a second-rate horror movie, there’s nothing to fear in this case. The sharks are mixes of two species of blacktip sharks, the common blacktip shark (Carcharhinus limbatus) and the Australian blacktip (Carcharhinus tilstoni).
While the former typically lives in temperate waters, the latter inhabits only Australian waters, along the tropical north and northeastern coasts. The new species lives in both types of water. Its habitat stretches more than 1,200-miles, from tropical Brisbane in the north to the chillier waters off Sydney in the south.
An expedition tasked with studying shark populations along Australia’s coasts discovered the species. The researchers first realized that they were dealing with something new when the genetic markers of one of the sharks showed up as one species, while the animal’s physical characteristics matched those of a different animal.
Hybridization in nature
The concept of hybrid species is not unknown in the animal world. The most commonly found species is the mule, which is a hybrid of a female horse and a male donkey. Killer bees also count as a hybrid species, and came about when scientists crossed a European honeybee with an African bee, ironically in an attempt to create a tamer, more manageable bee. Marine biologists have long thought that interbreeding between sharks, resulting in hybrid sharks, was theoretically possible. But this new discovery has moved the hypothesis from theoretical possibility to fact.
How many hybrids?
The 10 researchers who were part of the discovery identified several generations of the species and a total of 57 individual animals. This is the first species of hybrid shark ever found, and was the result of interspecies mating between the two types of blacktip sharks. Researchers hypothesize that the hybrid shark may be better equipped to live in oceans affected by global warming, as very few other species of sharks are able to exist in such diverse temperatures.
“We are now seeing individuals carrying the more tropical species genes in more southerly areas,” says Colin Simpfendorfer from James Cook University, one of the study’s co-authors.
“In a changing climate, this hybridization may therefore allow these species to better adapt to different conditions.”
While the idea of combining existing shark species and producing a new species with the best of both sounds like a Bond villain’s dream come true, we shouldn’t worry that we’ll now see hordes of super-sharks cruising the seas. The close resemblance between the two species makes interspecies mating much more likely than more diverse species of sharks, the researchers behind the study point out.
“It doesn’t mean we’re going to see great-white-tiger sharks anytime soon, or bull-Greenland sharks,” says Demian Chapman, assistant director of science at Stony Brook University’s Institute for Ocean Conservation Science If any species was going to hybridize, it was going to be this pair.”