Although all marine mammals evolved from land mammals, it may surprise some that each group of marine mammals has its own unique ancestry. There are three groups of marine mammals: the cetaceans (whales, dolphins and porpoises), the pinnipeds (fur seals, sea lions, walruses and seals) and the sirenians (dugongs and manatees). Through convergent evolution, each of these groups separately evolved similar body structures as they adapted to a life in the marine environment. Marine Mammal Groups The cetaceans have evolved to become the dominant group of marine mammals, with the highest levels of t ..read more

Cape Fur Seals Over the last few weeks, newborn Cape Fur seal (Arctocephalus pusillus pusillus) pups have been washing out on Robberg beach; most already dead, but a few lucky ones making it ashore alive. Cape fur seal pups are born between mid-November and the end of January. They are born with a black natal coat which insulates the pups and prevents them from overheating during their first few weeks when they are mainly ashore and exposed to intense solar radiation and high temperatures for long periods of time. Unlike the coat of adult Cape fur seals, this natal coat is not water-repellent ..read more

The Sunfish The largest bony fish in the world is the ocean sunfish Mola mola. These behemoths can grow up to a whopping 2.3 tons and 3.3 m! They are a very peculiar fish, and despite the size that this species can grow to, sunfish give the appearance of being half a fish – their tail does not develop but instead folds back on itself creating a scalloped, broad, stiff lobe called the clavus (which is Latin for rudder). As the vertebral column is severely reduced, besides not having a tail, sunfish do not have ribs either. With a laterally flattened body and tall dorsal and ventral fins, this f ..read more

The humpback whale (Megaptera novaeangliae) is one of the most well-studied species of baleen whale and occurs worldwide in all ocean basins. These whales are migratory and typically follow the usual baleen whale paradigm of moving between summer feeding grounds in high latitude regions and winter breeding grounds in low latitude regions. Different populations of humpback whales, which are more or less geographically separated, exist in different ocean basins. There is also little to no genetic interchange between populations in the northern and southern hemispheres due to limited trans-equato ..read more

Nursing underwater Whales and dolphins, being marine mammals, exhibit the typical characteristics of mammals: they’re warm-blooded, breathe air, have fur (although only a few hairs or for a limited time period), give birth to live young, and produce milk to feed their offspring. Calves of either whales or dolphins are able to swim shortly after birth, but are unable to hunt and feed and so are fed milk from the mother, with some species nursing for over a year! Without lips, and living in aquatic environment, you can appreciate the inherent difficulties of nursing. You can also appreciate the ..read more

Southern right whales are usually mostly black in colour and were often referred to as “black whales” by open-boat whalers. Most individuals also have a white blaze on their bellies, which can vary in size from a small spot to a large irregularly-shaped marking that may extend up the side of the animal and sometimes even up onto the back. However, southern right whale pigmentation is dependent on a specific gene on the X sex chromosome. The “normal” black colouration that is often seen is caused by the dominant allele (X) of this gene. Individuals born with the combination of alleles XX and X ..read more

What does conservation mean? What does it mean to be conservation-minded, to have a conservation ethic, or to do conservation? Conservation, specifically with regards to the environment, is a word that has possibly become overused in the past years, and perhaps the meaning has become diluted. Traditionally conservation had to do with the preservation, protection, and restoration of the natural environment, ecosystems, and resources. More recently, conservation has begun to include the examination, documentation, research, treatment, improvement, and preventative care of the natural environmen ..read more

On Tuesday 3 October, the Mammal Research Institute’s Whale Unit started their annual southern right whale aerial survey which aims to monitor the population of right whales along the South African coastline. This survey has been carried out annually since the first survey in 1979, making this year the 39th consecutive annual right whale survey and making the resulting dataset one of the longest running datasets on any marine mammal worldwide. The survey is conducted along the coastline between Nature’s Valley and Muizenberg, Cape Town, although on occasion it is extended westwards, rounding ..read more

Anyone who has gone scuba diving knows the difficulties of underwater vision. Visibility can be affected by the turbidity of the water, and the deeper you get the less light penetrates and you slowly lose colours, and then light altogether. Depth perception also changes due to the refraction of light, and objects may closer or further away than they are. Objects may also be blurry due to the scattering of light. Without a mask the salt water and particles irritate your eyes, and at depth the pressure becomes uncomfortable, not to mention a painfully frigid water temperature. The eyes of cetac ..read more

The Cape Fur seal (Arctocephalus pusillus pusillus) is the only pinniped resident to the South African coastline and breeds at 41 different sites between Baia dos Tigres in Angola and Algoa Bay in South Africa. Most of the colonies are situated on the west coast within the Benguela Current system, while only three are situated to the east of Cape Agulhas within the Agulhas Current system. The Robberg Peninsula colony in Plettenberg Bay is one of the few situated in the Agulhas Current system and has only recently been considered as a breeding colony. A breeding colony is defined as a colony w ..read more