Shark Navigation: Magnets?

Some species of shark are well known long distance travelers, often covering thousands of miles of open ocean in what appears to be an effortless fashion. Despite traveling these long distances, it has not been known until recently how sharks were able to navigate across wide stretches of open ocean and arrive at an exact destination. While turtles had been known for a while to navigate the open ocean using the earth’s magnetic field, sharks were a much more difficult study. Sharks are harder to study than sea turtles, making it hard to determine how they were navigating the open ocean.

The most recent study used bonnet head sharks, a relative of the well known hammer heads. The bonnet heads come back to the same place every year, and researchers wanted to know how they did it. Using wild caught juvenile bonnet heads, the researchers exposed the sharks to magnetic field conditions that were widely different from where they were found. The research predicted that if the bonnet heads were responding to the magnetic fields, they would orient themselves north when exposed to southern magnetic fields, and south when exposed northern magnetic fields. However, if exposed to normal conditions, there would be no change in orientation. Sure enough, the bonnet heads responded as expected.

Now it is important to realize that this is very preliminary data. Many more experiments need to be performed to confirm that the bonnet heads are using magnetic fields to help them navigate. Further, even if the bonnet head is using magnetic fields, that does not mean that other shark species are using magnetic fields. The researchers admit this and discuss plans for new experiments. it is important to keep in mind that more work needs to be done, but the early results are promising.

One of the researchers made the following observation which is particularly apt: “How cool is it that a shark can swim 20,000 kilometers round trip in a three-dimensional ocean and get back to the same site? It really is mind blowing. In a world where people use GPS to navigate almost everywhere, this ability is truly remarkable.” Said Bryan Keller, one of the researchers on the project. Notice something Dr. Keller said. Sharks can navigate the ocean, end up in the same place, and it is “mind blowing”.

Keep in mind, human GPS generally navigate using roads and require satellite data, and connection to work. Sharks have access to none of this. They don’t have handheld GPS, roads (though perhaps ocean currents might be a semi-equivalent), satellite data or a satellite connection. They do all their navigation internally. Whether it is purely based on magnetic fields, or involves ocean currents or some other factors, is somewhat immaterial to the point. Shark navigation being internal requires that they have built in systems to do so.

The existence of those systems strongly implies a design of some nature. When we look at human GPS systems we know obviously that these things are designed. Yet, when we look at sharks, they perform the same complex tasks, yet without the human designed tools, like satellites, GPS, or roads. Despite lacking all the tools that humans use, sharks are able to get to exactly where they want to get, without much difficulty.

We are just now learning how sharks do this. However, knowing how sharks navigate does not tell us where they got the ability to do so. In other words, just because there is a naturalistic explanation for how the sharks navigate, does not mean that there is a naturalistic explanation for how the ability developed. And that is the true question we need to be asking here. How did the shark develop its navigation capability? By some process of natural selection? The problem with a purely selectionist explanation is that selection can only be invoked on existing things. The sharks navigational system had to exist for selection to operate on it. Selection can fine tune an organism for its environment, but it cannot create new traits.

Without the selectionist explanation, the only remaining explanation is design. Now obviously evolutionists will not like this explanation, but it is the only one available. Obviously many design advocates will not appeal to the Christian God, but I certainly will. The only reasonable, rational explanation for the existence of design is the Christian God. But that’s an argument for another time.

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