Whale first for BBC natural history crew

A BBC natural history crew has filmed male humpback whales in Tonga, battling it out with rivals to mate with females.

During the first complete sequence of this behaviour ever captured, the male humpbacks swim at high speed behind the female, violently jostling for access. Up to 40 males swim behind a single female at speeds of up to ten knots, each jostling to obtain a dominant position. In order to capture the sequence the team had to film from a helicopter, a boat and from underwater.

When a female humpback comes into heat, she alerts males by making sounds, such as slapping the water surface, she may also release scent into the water to signal her status. The males all gather around the female, she hangs there, and then swims away at speed. The males then fight for pole position directly behind her tail.

As they chase the female, the males escalate their conflict. First they lift their bodies out of the water, slapping the bottom of their huge feeding pouches onto the surface. They also slap their long pectoral fins onto the water. The males then vocalise loudly and blow bubbles underwater, a threat display among many marine mammals. The males then start colliding, hitting one another and even jumping out of the water and onto rivals. Considering that each male humpback can weigh 40 tonnes, such collisions must hurt and there are records of males killing one another.

The footage was recorded for the BBC natural history series 'Life'.