Hector’s Dolphin or White-headed Dolphin (Cephalorhynchus hectori) is the most well known of the four dolphins in the genus Cephalorhynchus. At about 4.5 ft (140cm) in length, it is one of the smallest cetaceans.
Hector’s Dolphins have a unique rounded dorsal fin. The Dolphin has no discernible beak and a rounded fin. The fluke has pointed tips and concave trailing edges. The overall color is a pale grey but closer inspection reveals a multitude of colors. The forehead is grey with streaks of black. The tip of the beak is black. The throat and chest are white. Above that there is a dark grey patch running from the flippers (also dark grey) to the eyes. The belly is also white with a stripe running up the sides from under the dorsal fin. The bulk of the back and sides is the same lighter gray of the beak. The tailstock is narrow. At birth the animal weighs about 19 pounds (9kg) and grows to about 85-120 pounds (40-60kg) at adulthood. They live for about 20 years.
Hector’s Dolphins live in fluid groups of about two to eight in number. They are active animals, readily bow-riding and playing with seaweed. When leaping from the sea, individuals will often land on their side, creating a loud splash.
Some sharks prey on Hector’s Dolphins.
Population and distribution
Hector’s Dolphins are endemic to the coastal regions of New Zealand. There are two known main populations, one on each side of the South Island. The two populations are believed to largely cut off from one another by deep water at Cook Strait and at the southwest tip of the South Island. The species seems unwilling or unable to cross-areas of deep water. The total population was estimated to be around 3,500 in the mid-1980s. A more recent survey suggested a total population of only 2,000 to 2,500 individuals. A notable population exists at Akaroa, near Christchurch, New Zealand.
Hector’s Dolphins are sighted always less than 5 miles (10km) offshore in summer and only slightly further in the winter.
Photo by: Malene Thyssen, www.mtfoto.dk/malene/