Author: Morgan Cadle
What to Expect of the Sperm Whale in South Africa
Southern Africa’s tropical waters offer a unique environment for Sperm Whales, especially during their winter migration from June to November. More specific spots that South Africans can expect to see this whale are Hermanus, Plettenberg Bay, Algoa Bay, False Bay, and Durban.
People who go on a boat-based whale watching tour have the opportunity to witness these beautiful creatures engage in breeching, tail flapping, spy hopping, mating, calving, and even socializing.
The Sperm Whale, Physeter macrocephalus, is a majestic giant of the ocean, well-renowned for its monstrous size and deep-diving capabilities. This magnificent creature is yet again one of the many marine mammals that can be found along the South African coastline.
This whale got its common name from a substance found in its head called spermaceti. This substance was encountered by whalers, and to them, it resembled a thick, milky oil, which they believed to be sperm. So, they gave the creature the name ‘sperm whale’. Its scientific name is also a reflection of its head. ‘Physeter’ comes from the Greek word for ‘blower’, referring to its blowhole, while ‘macrocephalus’ is the Greek word for ‘big head’, describing the whale’s most prominent feature.
The Sperm Whale has a long lifespan, normally living up to 70 years in the wild, but there have been some cases of some whales living even longer than that. The oldest known Sperm Whale recorded was estimated to be around 77 years old.
The Sperm Whale is the largest toothed whale, and because of their heads that take up about a third of their body, they house the largest brain of any animal on Earth. The males can reach lengths of up to 20.5 meters (about the size of a large yacht) and weigh up to 57,000 kilograms. The females are a bit smaller, typically growing to about 12 meters (about the size of a delivery truck) and weighing around 15,000 kilograms.
Distribution and Migration
Sperm Whales inhabit all the world’s oceans, all the way from the equator to the edges of the polar ice. This species is commonly spotted along coastlines, especially where deep waters are close to the shore. They are frequently seen off the coasts of South Africa, Namibia, and Mozambique, with the prime time for these sightings during the winter months from June to November.
These whales are known for their extensive and complex migration patterns. Unlike some whale species that have distinct seasonal migrations between feeding and breeding grounds, the Sperm Whales’ migrations are less predictable and can vary widely.
Southern Africa is a key region for Sperm Whale migrations, mostly from June to November. During winter, they migrate toward the coastline along Southern Africa because these waters provide a rich feeding ground. The warmer waters around South Africa also serve as essential breeding grounds, and females and their calves are commonly seen in these regions.
Breeding and Gestation
The Sperm Whale has distinct and fascinating breeding habits that revolve around their social structures and migratory patterns. They breed in the warmer waters, typically in tropical and subtropical regions. The breeding usually peaks during spring and summer months, so around December to March.
The males often compete for access to the females by engaging in physical displays and fights. The larger males are often the victors of these fights and are more successful in mating than the smaller males. Other behaviours they use to attract the females include ‘sailing,’ where they raise their heads out of the water and swim slowly in a circular motion to showcase their large heads and jaws. They also produce distinctive vocalizations, known as ‘click trains,’ which are believed to play a role in mate attraction and communication with females. These vocalizations are believed to convey certain information about the male, such as its size, strength, and reproductive fitness
Once they have fallen pregnant, the female Sperm Whale’s gestation lasts about 15 to 16 months resulting in them giving birth to a single calf every two years. These calves are quite large at birth, measuring about 4 meters and weighing about 900 kilograms. This size is necessary for survival in the vast and often harsh ocean environment.
Feeding Habits
These whales are apex predators, and their hunting capabilities show it. They can dive to depths of over 2,000 meters—that is twice the height of the Burj Khalifa! They can also hold their breath for up to 90 minutes. This incredible diving capability, plus their advanced echolocation skills, allows them to hunt effectively in the dark depths of the ocean. While these animals usually hunt on their own, they can sometimes coordinate their diving and surfacing times with other members of their pod.
Their diet famously consists of squid, mostly large species like the giant squid, and the colossal squid. They also consume many types of deep-sea fish, such as deep-sea sharks and rays. They may also feed on octopuses, crustaceans, and smaller whales, and dolphins. It is worth noting that these are not the primary components of their diet, so they are not consumed as much.
Common Traits
The Sperm Whale has been known to exhibit a range of highly fascinating behaviours that have captivated researchers and whale watchers for years. They can be seen breaching out of the water for heights up to 3 to 5 meters and engaging in tail flapping, which produces a loud slap on the water’s surface. Another common behaviour that can be observed is spy hopping, where they vertically poke their head out of the water— can you imagine seeing such a massive head poking out of the water?
Conservation Status
The Sperm Whale is currently listed as Vulnerable on the International Union for Conservation of Nature (IUCN) Red List. This status shows us that this whale is still facing threats despite significant efforts to protect and conserve them. The primary threats to this species include historical whaling, ship strikes, entanglement in fishing gear, noise pollution, chemical pollution, and climate change.
Scientists estimate that today there are approximately 200,000 to 300,000 Sperm Whales globally.
