Humpback whale (Megaptera novaeangliae) calf. This calf is part of the Tongan tribe population, which migrates from feeding grounds in Antarctica, past New Zealand to breed in tropical waters around Tonga in the Pacific. The humpback whale can grow to 27 tonnes in weight and 15 metres in length. It feeds in cold waters on krill and small shoaling fish, breeding in shallower tropical waters. Calves are four to five metres long when they are born and they suckle for about five months. Photographed off Tonga.