VIDEO: Thousands of female sharks gather for a slumber party in Australia. 'We don’t know...'

Researchers have filmed a group of bizarre-looking sharks in Australia sleeping on the ocean floor and appearing to form a carpet. They have blanketed the floor of the Beagle Marine Park park and number in thousands. These sharks were first found years back in the coastal region of southern Australia called Port Jackson and were later named after it.

A press release from the University of Tasmania stated that thousands of these blunt ridge-nosed predators were found on the ocean floor. They are "tightly packed like a carpet spread across the seafloor", UTAS researcher Jacquomo Monk said.

Interestingly, thousands of these sharks were found in the exact peculiar pattern in the same region six years back as well.

The sharks were filmed schooling using an aquatic robot equipped with a camera and operated remotely from a government research ship floating above.

Shark cluster spots

Shark schooling cluster spots are not uncommon and several of them have been observed across the world. The reason for this aggregation of the sharks is not known. Experts are still trying to understand what makes these sharks come together and slumber together in "aggregation spots".

Another fascinating thing the scientists noticed is that "the Beagle gathering appears to be only for females", Monk said. Notably, Port Jackson sharks don't mingle with the opposite sex in their daily lives. So female sharks live only with females and males only with males. They only mix up during the mating season.

While that might explain why only female sharks were at the aggregation site, researchers don't know why all of them go into a slumber together.

"We don’t know exactly why the females are here," Monk said in the press release. "Perhaps they are feasting on the local delicacy — doughboy scallops — before the long trip north to lay their eggs."

So scientists now know three things -- that they are all females, the sharks have gathered at the same spot in the past and that they will likely do it again. They are now trying to understand the significance of the region since they did the same activity there six years back.

Monk said, "Seeing them again does tell us that the area is important to them."

Port Jackson sharks

Port Jackson sharks are a migratory species that move south in the summer and return north to breed in the winter. It has a large, blunt head along with forehead ridges. They can grow up to 1.65 metres (5.5 ft) long and are the largest in the genus Heterodontus. It is endemic to the waters around southern Australia.