The brownish cat shark is covered with small, dark dots, its long body flat on the stony ground. Its inconspicuous dorsal fin is round, its cat-like eyes aimed toward the emptiness of the basin.

Two more cat sharks float above the ground on either side. A group of scientists from the Marine Biological Association of the UK and the University of Exeter have been examining the personalities and social behavior of the three sharks in large tanks for some time. Their hope? To reveal that sharks' behavior is driven by individual character traits.

Lab observations

As they watched the cat sharks, scientists found that there existed both gregarious and antisocial animals. According to the scientists, individual traits are responsible for the social behavior sharks tend to show.

Gregarious sharks, not surprisingly, prefer forming groups. Their motto appears to be: "together we are strong." Every single shark is protected against enemies by the group, raising the likelihood of survival by staying together.

Contrary to the gregarious sharks, loners embrace the advantages brought with secrecy: The fewer the sharks, the less they make waves, so to speak. These sharks prefer hiding rather than looking for confrontation, even if there is no ideal place to hide close by.

This represents the first evidence for the presence of personalities in sharks, according to the scientists.

"Up to that point, we hadn't been aware of that kind of behavior in sharks," said Jens Krause of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries in Berlin.

'We know almost nothing'

Though Krause did not participate in the cat shark study, together with his colleagues, he often dons a rubber suit and diving mask to observe lemon sharks in the open water. The yellowish sharks are almost four meters (13 feet) long and gather around the westernmost district of the Bahamas, known as the Bimini islands.

"We've observed whether lemon sharks show behavioral types and personality structures we know from other animals," Krause says. "The adolescent sharks in particular form swarms to protect themselves from predators."

The young lemon sharks spend the first two years of their lives in the shallow water around the island. Those conditions are ideal to study their behavior.

Despite the fascinating cat sharks results from Great Britain, however, Jens Krause says it is too early to apply those findings - or his own with lemon sharks, for that matter - across shark species.

"We chose a special kind of shark. A lot of social behavior had been observed previously." According to the scientists, it will take more time to obtain results that can be generalized.

In a corollary conundrum, the scientists at the Leibniz Institute have immense knowledge about boney fish like bass and pike. The freshwater fish also engage in complex social structures and behavior.

Yet neither are these findings transferable, for the time being, to the sharks to which they're related.

Threatened ruler

The results from Great Britain clearly show that sharks are not just killers controlled by their instincts. That false impression has unfortunately helped ruin the image of these fascinating animals.

There are around 460 kinds of shark; a staggering one in three is threatened.

Mankind has contributed much to that development through hunting and unintentional catches.

But without sharks, the marine ecosystem would be on the verge of collapse. Sharks are the first link in the food chain. They regulate the size of other populations and keep the sea healthy by eliminating sick or weak individuals.