1. Humpback whales are found in all major oceans of the world in distinct populations and typically migrate each year up to 25,000km. They have a stubby dorsal fin, a stocky body and elongated pectoral fins.
2. Humpback Whales are extremely flexible and use their pectoral fins, which can be 6m long, to help them manoeuvre. They are air-breathing mammals so have to surface to breathe.
3. Whales were hunted for their oil to the brink of extinction until the 1960’s but their numbers are now recovering. It’s estimated there are over 50,000 in the Southern Hemisphere.
4. When humpbacks surface to breathe they expel the air through a heart-shaped blowhole, then they use their fluked tail and pectoral fins to dive. In the southern hemisphere winter around Tonga, they live off their fat reserves before returning to polar waters to feed in summer.
5. Humpbacks can contort their bodies into many different positions as they appear to effortlessly glide through the water. They are often curious of humans in or on the water and these “friendlies” may come in for a closer look and even stay around for several hours.
6. Gazing into the eye of a curious humpback is a breathtaking experience as they radiate “intelligence” as they look back at you. They are baleen whales with special plates on the side of their mouth with which they filter swarms of krill and small fish.
7. Humpback cow and calf lolling around as they rest in clear waters in Tonga. Each southern winter, humpbacks migrate to the warmer waters here and to other areas to calve and mate.
8. Calves nurse for 6 -12 months on milk which is rich in 50% fat and stay with their mother for some time after this. Baleen whales give birth more often than toothed whales but wean their young comparatively quickly.
9. Young humpback whale with eye closed, resting. Newborns are about 6m long and weigh about 2 tonnes. It’s been suggested that only half their brain sleeps at one time, while the other half stays awake.
10. Females breed every 2-3 years with gestation being nearly 12 months. In Tonga the peak time for births is July-August.
11. The cow creates a pressure wave as she swims and the young calf effortlessly capitalises on this, so keeping up with its protective mother.
12. Individual humpback whales live alone or in small temporary groups to feed cooperatively. Males are slightly smaller than females averaging about 14m in length and weighing 30 tonnes or more.
13. In winter, males compete for access to females. Escorts often trail females with or without calves and will compete for the right to mate with her.
14. Two humpback whales hanging vertically in water column, Tonga. Closest one appears to be observing the photographer. You sense that behind the large eye there is a cognizant being.
15. Competition for females can be aggressive and male-to-male threats include bubbles streaming from the blowhole. Males seem to establish a dominance rank by display, songs and fighting.
16. Curtains of bubbles rise to the surface as humpback whales vocalize deep below. No one knows really why they sing but it may have something to do with mating or establishing dominance. Both males and females vocalize by forcing air through their blowholes but only males sing complex songs which they repeat. Some sing for 20 minutes at a time with sounds varying in pitch.
17. Humpback whale leisurely rolling around after surfacing to breathe. Wide ventral grooves run along its underside with females having a 15cm diameter hemispherical lobe in the genital region. This distinguishes them visually from males who generally have their penis hidden within a genital slit. Males reach sexual maturity when about 7 years old and the females at about 5 years.
18. We don’t know if the other animal nearby was female or male but the penis extrusion followed a long stint of two whales surfacing and diving to rest at about 10m. Sometimes the pair would lie across each other while at other times they would just hang vertically in the water column head up. Our collective sense was that it was courtship.
19. A mature male humpback whale’s penis ranges from 3.2 to 6.2ft in length and it’s unusual to see it extruded. Males may display it to other males as they compete for a female or as part of courtship.
20. Humpbacks compete for females physically not through sperm competition as do other whale species like right whales. They have relatively small testes and a short penis and they fight.
21. Spy-hopping humpback whale, Tonga. Their topside is usually black and their head and lower jaw are covered in knobby hair follicles called tubercules.
22. Tail slapping humpback whale with water cascading off the wavy trailing edges of its powerful tail. The tail fin can be up to a third of the humpback’s body length. Varying patterns on these flukes allow researchers to distinguish individual animals and photo ID catalogues of the different populations are added to each season. Tail lashes can also be part of surface active groups fighting for a female.
23. Humpback whale slapping its pectoral fins, typically one-third the length of its body. Flipper slaps are often seen in surface active groups battling for access to a female. These fins are proportionally the longest of any cetacean and it’s been suggested they have evolved to give them better manoeuvrability and increased surface area for temperature control during their migration across warm & cold waters.
24. Young humpback whale breaching, It’s uncertain why whales breach. It may be to remove parasites, to communicate a message, to intimidate a rival, to see what’s going on or just to play. In any case, humpbacks seem to do a lot of it to the delight of onlookers.