It was due to be a routine mission to examine the depths of the Gulf of Mexico . However , researchers were stunned when their underwater robosub had an unexpected encounter almost 2,000 feet under the ocean . Rather than the deep sea squid and corals they expected to see , a giant sperm whale swam to inspect their sub - causing gasps and shouts of 'holy cow ' from the sub 's operators . Scroll down for video . The robot sub was examining the depths of the Gulf of Mexico when the sperm whale suddenly appeared . The sperm whale is the largest toothed whale . Adult males reach 16-20 meters ( 50-65 feet ) in length , although most are less than 18 meters ( 60 ft ) . Females are much smaller than males , reaching only 11 meters ( 36 feet ) on average . The sperm whale 's life is based on sound . It finds food and navigates using sound and it communicates and stays in touch with its family using sound . Sperm whales are listed as an endangered species under the U.S . Endangered Species Act . The global population size is estimated as somewhere between 100,000-300,000 animals . 'What the heck is that ? ' says one of the crew , when all of a sudden a massive object begins to appear on the screen . 'Hello baby , ' says another . 'At 598 meters ( 1,962 ft ) below the Gulf of Mexico off the coast of Louisiana , ROV Hercules encountered a magnificent sperm whale , ' 'The whale circled several times and gave our cameras the chance to capture some incredible footage of this beautiful creature . 'Encounters between sperm whales and ROV 's are quite rare . ' Footage shows the curious leviathan swimming in and out of the camera lights , at times spinning and looking directly into the camera . 'You can see its eye , ' one of the crew says . 'According to biologists we 've consulted , the animal on the video is likely a juvenile , especially if it 's a male , ' they say . 'General consensus among the experts who have examined the video is that it is a male , though the video of the underside of the whale is grainy so it is difficult to know with 100 % certainty . ' It was difficult to tell the actual size of the whale , the team say , but the ROV is 6 feet wide in the front . Using this as a guide , and how close he was to the vehicle , it is estimated the whale was between 35-40 feet in length . The team also investigated the scarring visible on the whale . 'It could be a number of things , including squid tentacles and suckers , especially the scars around the efface and mouth ; but likely not propeller scars like the comments made in the video . This neutrally buoyant yellow remotely operated vehicle ( ROV ) is the workhorse of the Nautilus Exploration Program , and it always used in tandem with Argus , it 's mothership . Hercules is equipped with six thrusters that allow the pilots to 'fly ' it in any direction . It has two manipulator arms designed for collecting samples and recovering artifacts . Video from Hercules ' high-definition main camera is streamed up a fiber-optic cable to the control van on Nautilus , then out to the world . It is capable of operating down to 4,000 meters . 'It could also be from other sperm whales . 'They often jaw each other when playing or socializing . 'Sperm whales are identified with the scars on the trailing edge of their tails . ' The whale can be seen inspecting the robosub in the video . The researchers were piloting the Hercules sub when the encounter occured . This neutrally buoyant yellow remotely operated vehicle ( ROV ) is the workhorse of the Nautilus Exploration Program , and it always used in tandem with Argus , it 's mothership . Hercules is equipped with six thrusters that allow the pilots to 'fly ' it in any direction . It has two manipulator arms designed for collecting samples and recovering artifacts . Video from Hercules ' high-definition main camera is streamed up a fiber-optic cable to the control van on Nautilus , then out to the world . It is capable of operating down to 4,000 meters . Dr. Robert Ballard ’ s Exploration Vessel E/V are on their most ambitious expedition season yet , exploring sites ranging from the Gulf of Mexico to British Columbia through late September . Over six weeks of the six-month expedition will be dedicated to exploration and mapping of the Galapagos Rift and the site of the first hydrothermal vent discovery in 1977 . The six-month-long 2015 season marks the transition of the vessel and operations of the Ocean Exploration Trust ( OET ) to the west coast of the United States and the Pacific Ocean , concluding over two years of research in the Gulf and Caribbean regions . E/V Nautilus is owned and operated by the Ocean Exploration Trust ( OET ) , a nonprofit founded in 2008 by Dr. Robert Ballard .
Robosub was exploring the Gulf of Mexico off the coast of Louisiana . At 36 feet the sperm whale appeared in the robosub 's cameras .