Author: Morgan Cadle
What to Expect of the Humpback Dolphin in South Africa
In Southern Africa, these dolphins can be found along the coasts of countries such as South Africa, Mozambique, and Namibia. These regions offer the dolphins a range of diverse marine habitats, including sandy beaches, rocky shorelines, and estuaries. Each of these habitats provide ideal conditions for humpback dolphins to thrive.
This species of dolphin does not have a long migratory pattern, sticking to more local areas, but they can be seen during the warmer months from October to March. There are certain parts of South Africa where one might have a better chance of spotting them. Those places are St. Lucia Estuary, Plettenberg Bay, Algoa Bay, and False Bay.
If you manage to spot them while on a boat, typical behaviour that can be observed includes breeching, tail flapping, spy hopping, calving, mating, and swimming at high speeds of around 24 kilometers per hour.
The Humpback Dolphin, or as scientists know it Sousa spp., is a fascinating creature that inhabits coastal waters around the world. This beautiful creature is another intriguing marine mammal that South Africans can spot along their coastlines.
This species of dolphin got its common name from the distinctive hump or ridge that can be observed behind its dorsal fin. This physical feature sets it apart from other dolphin species and serves as a recognizable trait for identification. Its scientific name, Sousa spp., reflects its classification within the genus ‘Sousa,’ which involves several species of Humpback Dolphins found in different rejoins. This specific label assigned to each species within the genus further distinguishes them from one another. There is a total of four species of Humpback Dolphins which includes the Atlantic Humpback Dolphin (Sousa teuszii) and 3 types of Indo-Pacific Humpback Dolphins (S. plumbea, S. chinensis and S. sahulensis).
On average, the Humpback Dolphin is believed to have a lifespan of around 30 to 40 years old. Like other species of dolphins, this lifespan is for the dolphins living in the wild, while certain dolphins in captivity have been known to live longer because of certain conditions such as lack of predators and veterinary care. The oldest Humpback Dolphin was a female Indo-Pacific Humpback Dolphin (Sousa chinensis) named Billie. She lived at the Brookfield Zoo in Chicago, Illinois, USA, and lived to be approximately 55 years old.
Humpback Dolphins vary in size depending on their specific species and location. On average, they measure 1.8 to 2.4 meters, while their weight typically falls between 90 to 140 kilograms (about half the weight of a large motorcycle).
Distribution and Migration
These dolphins are found along the coasts of various regions, including the Indo-Pacific and Atlantic Oceans. They like to inhabit shallow coastal waters, estuaries, and mangrove swamps, preferring areas with abundant food sources and suitable habitat conditions. While Humpback Dolphins can be observed year-round, they are often sighted more frequently during certain seasons, depending on their location and environmental factors. In some regions, sightings may peak during the warmer months when they are more active and visible. For South Africa these warmer months fall between October and March.
These dolphins are generally do not engage in long-distance seasonal movements like some other species of dolphin. So, they prefer to inhabit specific coastal areas through the year where they have a suitable habitat and enough sources of food. However, in their coastal range, these dolphins may show localized movements because of changes to the conditions of their environment, availability of prey, or social dynamics.
In some cases, Humpback Dolphins may also display short-distance movements associated with mating or calving activities. During these periods, individuals may gather in specific areas where mating occurs, or where the females give birth to their calves.
Breeding and Gestation
Mating among Humpback Dolphins can occur year-round, although there may be seasonal peaks in breeding activity for some populations. Sometimes, the timing of mating can vary because of certain factors such as environmental conditions, prey availability, and social dynamics within their communities.
To attract a female, the male Humpback Dolphin will engage in various behaviours and displays, each with the purpose at demonstrating their strength, fitness, and reproductive prowess. These behaviours include competitive displays, such as chasing or wrestling with rival males. They also engage in vocalizations of whistles, clicks, and burst-pulse sounds to convey information to the females, such as their identity, fitness, and reproductive status. They engage in physical displays such as leaping out of the water (breeching), slapping their flippers or tails on the water’s surface, or performing acrobatic movements that show their strength, agility, and vigor. Lastly, they can form alliances with the females in their group or even with other males to enhance their success with mating.
Once pregnant, the female dolphin’s gestation period typically lasts around 12 months, after which a single calf is born every 2 to 3 years. The claves typically measure around 0.8 to 1 meter (80 to 100 centimeters) in length and weight approximately 10 to 20 kilograms at birth.
Feeding Habits
Humpback Dolphins use echolocation to locate and capture prey. The sounds produced from the dolphins will bounce off objects in their environment, giving them a mental map of their surroundings, helping them capture their prey. These creatures are primarily piscivorous, which means they mainly eat fish. However, their diet can also include crustaceans, cephalopods, and other small marine organisms.
Common Habits
The Humpback Dolphin has been known to exhibit a range of behaviours that include breeching, tail flapping, spy hopping (where they poke their head out of the water to examine their surroundings), and socializing with other dolphins. They are known for their playful nature, often seen riding waves and interacting with objects in their environment.
Conservation Status
This species is generally classified by the International Union for Conservation of Nature (IUCN) as ‘Vulnerable.’ However, it’s important to note that there are different species and subspecies of humpback dolphins, and their conservation status can vary. The Indo-Pacific Humpback Dolphin is listed as ‘Vulnerable’. The Indian Ocean Humpback Dolphin is classified as ‘Vulnerable’ as well and lastly the Atlantic Humpback Dolphin is currently classified as ‘Critically Endangered’.
