Tony Wu / Humpback whale (Megaptera novaeangliae australis) female with suckling calf. Vava'u Islands, Tonga.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) male calf playing at ocean surface after coming up to breathe. Vava'u Islands, Tonga.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female breaching. Vava'u, Tonga. Pacific Ocean.

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis) female nudging her mother's mammary gland whilst trying to feed. Vava;u, Tonga, South Pacific.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female, stationary with calf heading to surface for breath of air. Vava'u, Tonga, South Pacific.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female with calf swimming above head. Rake marks on fluke created by Orca or False Killer whale predators. Vava'u Islands, Tonga.

Tony Wu / Humpback whale (Megaptera novaeangliae australis) female and calf swimming together at depth, ventral surfaces of both whales clearly visible. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis) male calf launching partially out of the water with his mouth open while playing together with mother. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis) swimming just under the ocean surface, partially backlit by dramatic rays of sunlight. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis). faeces. Defecation like this from calves contributes to the cycling of nutrients from nutrient-rich high latitudes to less nutrient-abundant low...

Tony Wu / Humpback whale calf (Megaptera novaeangliae australis) female calf breaching sequence. Vava'u, Tonga, Pacific Ocean.

Tony Wu / Southern humpback whale (Megaptera novaeangliae australis) executing face flop after breaching. Vava'u, Tonga, South Pacific. Sequence 2/2.