Testosterone courses through the air as three-tonne leviathans rise from the depths of the ocean. We are tracking a competitive group of male humpback whales in Mexico’s Sea of Cortez. They are vying for the opportunity to mate with a lone female and the selection process is a brutal test of physical stamina. The whales race in pursuit of the female, swimming at speed whilst battling each other with bruising body blows and swipes of barnacle-encrusted pectoral fins. The effort can be heard in their breathing, transformed from peaceful blows to an intense chugging. The colossal power and size of these 14-metre-long animals sends my heart-rate racing. A dozen males are fighting for supremacy and there can be only one victor. When an individual falls out of the race, he pounds the water in fury, oversized pectoral fins and robust peduncle used to whip up a bath of foamy water. All around us we spot the tell-tale blows of whales. They are here in huge numbers, brought together to raise their calves and procreate the next generation. These ocean giants can lift their entire bodies out of the water. It’s a behaviour taught from the earliest ages, and we watch mothers demonstrate it to their young before the calf attempts to replicate the skill with the clumsiness of a toddler. The breaches are believed to be primarily social behaviour, a form of communication between whales, but it also gets rid of parasites and dead skin.

I am here with Dr. Esther Jiménez López and Dr. Hiram Rosales Nanduca, Mexican professors at the Autonomous University of Baja California Sur, and the scientists behind the Marine Megafauna & Fisheries programme (MMAPE). They have devoted their lives to the study and conservation of cetaceans, working in one of the richest regions in the world for marine mammals. Of the 90 recognised species of cetacean, 38 can be found in Mexico, and of those 32 can be found in the Gulf of California. By operating from the Baja California peninsula, Esther and Hiram have the extraordinary possibility of accessing 35% of all the world’s cetacean species. The reality, however, is more nuanced. As ever when dealing with ocean giants, finding and studying them is a very challenging proposition.

Aimed at unveiling the mysteries of the humpback whales, this is a team expedition. The Oceanographic & Arksen storytelling grant will directly fund the mission logistics, while Dr. Olaf Meynecke, manager of the whales and climate program at Griffith University, has come all the way from Australia, equipped with two Customised Animal Trackings Solutions (CATS) tags. We are united during high season for the migratory humpback whales, most of which have travelled thousands of miles from Alaska and Canada. The competitive group of humpback whales is too preoccupied to be concerned when our panga – the fibreglass style of boat commonly used by Mexican fishermen – joins the race. Hiram manoeuvres with the expertise gained from 20 years of cetacean fieldwork, anticipating the animals’ movements with uncanny skill. Olaf and Esther stay ready at the bow, while a telescopic pole hangs over the ledge with the CATS tag ready for deployment. These tags are non-invasive and use suction cups to attach to the whale for a short period of time before releasing through a galvanic reaction to seawater.