Speartooth sharks, one of the world's most rare shark species, were discovered in 1982 in Bizant River, Australia. For decades, the elusive sharks have succeeded in evading scientists until recently when researchers from Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO) captured and tagged two adult speartooth sharks for research.

The historic capture took place in the Wenlock River, located at Queensland's Cape York Peninsula. It was the first time live specimens of adult speartooth sharks were recorded in history around the world.

"From a conservation perspective it's really important to know where these adults are. They're a species that's listed as critically endangered so it's important to know what threats the adults might face," said Dr. Richard Pillans, CSIRO researcher.

The CSIRO and Australia Zoo research team looked into prior research done on the speartooth sharks' life cycle, which led them to Wenlock River where they searched for adult females who are due to visit the river's mouth as they give birth. After nine days of waiting, the team consisting of Dr. Pillans, Luke Burnett and Barry Lyon from the Australia Zoo caught two adult specimens, one male and one female. Pillans explained that the mating and birthing areas are often the same as it is a convenient place to meet.

The female speartooth shark measures 2.2 meters (7.2 feet) in length while its male counterpart measures 2.3 meters (7.5 feet). The two sharks were marked with satellite tags which will automatically disengage after two months. The tags will provide the research team with details on the sharks' movements, water depth and temperature. All these will help the scientific community to finally shed light on the species' habitat preferences and potential threats to their survival.

Often mistaken for the bull sharks, the speartooth sharks have distinct a dark gray backside color and a second back fin. Aptly named, this shark species' lower jaw bears spear-like teeth.

Scientists believe that the female speartooth sharks give birth to their young at the mouth of several rivers in northern Australia. Their young are fully independent and are capable of moving upstream, approximately between 40 to 80 kilometers (25 to 50 miles) from the river's mouth where the water's saline level is lower. The young speartooth sharks are believed to stay there for the next three to six years but during the annual monsoon, they swim downstream and return when the water's salinity level returns to normal.