Shark Hybrids

Amazed scientists in Australia have discovered 57 hybrid black-tip sharks off Australia’s east coast. Confirmed by genetic markers, the 57 specimens are hybrids of two species of black-tip sharks that normally inhabit waters of different temperatures. Some are offspring of hybrids, demonstrating the hybrids are fertile, and all appear to be in good health. Morphologically, they have characteristics of both parent species.

The scientists, whose work was recently published in Conservation Genetics, are unsure whether the unprecedented shark hybridization is an adaptation to climate change or a response to changes in food availability. Bob Hueter of the Sarasota Center for Shark Research commented, “In a sense, it is catching evolution in action.”1

Lead researcher Jess Morgan of the University of Queensland agrees. “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. This is evolution in action,” he says. “If it [the tropical Australian black-tip] hybridises with the common species [the common black-tip] it can effectively shift its range further south into cooler waters, so the effect of this hybridising is a range expansion. It's enabled a species restricted to the tropics to move into temperate waters.” The hybrids do not seem to be endangering the pure populations even though they now comprise up to 20 percent of the black-tip shark population in some places.

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. This is evolution in action.

Although scientists have not previously known of sharks hybridizing, there is no reason to term this “evolution in action.” A created kind of creature may contain multiple species generally able to interbreed. We use the term created kind because Genesis records God made each kind of living thing to reproduce “after its kind.” These sharks were able to interbreed because they were of the same created kind, not because they were evolving into a new kind of creature. They were reshuffling genetic material the parent species already had.

Variation and speciation occur within the created kind. The two parent species in this case thrive in different habitats. Genetic differences between species can accumulate when populations are isolated and render interbreeding no longer feasible. However, these hybrids prove such genetic incompatibility has not developed between these populations.

These sharks demonstrate God’s principle of reproducing “after their kinds,” not “evolution in action.”