Marine Mammals

Marine mammals are a large and diverse group of 129 species that include seals, whales, dolphins, walruses and even polar bears. They share relatively few biological characteristics, but are instead grouped together because of one common factor – they all rely on the ocean for their existence.

The Marine Mammal Collection includes a comprehensive collection of cetacean and Cape fur seal skeletal material, as well as those from other marine mammals. Cetaceans (whales and dolphins) are the largest and most diverse order of marine mammals.

Part of this collection is on exhibit in the museum’s Whale Well.

Fossil Cetacean Collection
This palaeontological collection consists of 142 rostra as well as other fossilised cetacean remains, including cochleae, teeth and postcranial material. A few fragments show cut marks, presumably from predation or scavenging by very large sharks such as Megalodon. Rostra are, typically, difficult to identify beyond broad family groupings because the samples often get caught in fishing nets. Such specimens are also impossible to date as no reliable geological context – the environment in which these animals originally lived – exists.

Extant (living species) Cetacean Collection
This collection consists mainly of skeletal material and casts, as well as a small wet collection of tissue and organ samples. As whales and dolphins are a protected species under South African law, they may not be harmed or disturbed in any way. Instead, material for the Iziko collections were obtained from three primary sources: from fisheries when whaling was still legal (so some of the oldest skeletons date from the early 1900s); from the accidental death of dolphins and whalestrapped in trawl nets and or old fishing gear; and from ‘strandings’, the term given when whales and dolphins inexplicably beach themselves, or when the carcasses of dolphins and whales who died in the ocean subsequently wash ashore. The majority of the material in the collection is from strandings.

The list of such extant cetaceans in the Marine Mammal Collection is extensive. It includes specimens from a globally representative selection of dolphin and whale orders and families, including Sperm Whales, Blue Whales, Humpback Whales, Common Dolphins and Bottlenose Dolphins.

Articulated Whale and Dolphin Skeletons and Casts on Display
The casts of articulated whales and dolphin skeletons seen in the Whale Well at the South African Museum have been painstakingly put together. It’s a patient process that begins with a mould of beached whale or dolphin using either plaster-of-paris or glass fibre and resin, which is then reshaped, modelled and finally air-brushed when necessary. Great care is taken to ensure that the casts are morphologically correct, and the colours of the animals are faithfully reproduced. The most impressive piece – the centre piece – in the collection is the Blue Whale skeleton. Below it is the mandibles (the bone of the lower jaw) of an even larger individual. The full display is made up of 16 casts of whales and dolphins.

Archaeological remains
Bones of whales and dolphins occur in small numbers in coastal archaeological sites. Such material is housed in Iziko’s Social History collections. Also on display, particularly on the humpback cast in the Whale Well, are pelagic coronuline barnacles, which attached themselves to larger whales. These barnacles, dated to the Later Stone Age and even Middle Stone Age, are evidence that blubber and meat from stranded whales had been harvested from strandings over a very long period. The barnacles have been recovered from archaeological shell middensfound in various sites in the Western Cape.

Keywords

Cetacean: The grouping of marine mammals that include whales, dolphins and porpoises.
Extant: Animals still in existence today
Order: A category in the biological classification of organisms.
Family: A category in the biological classification of organisms.
Palaeontological: Referring to the study of fossils.
Rostra: In biology, the beak or beaklike parts.
Cochleae: The spiral-like cavity of the inner ear.
Postcranial: All parts of the skeleton except for the skull.
Cast: The full-size replica of an animal.
Articulated: Having joints.
Predation: The preying of one animal on another.
Megalodon: An extinct species of shark that lived about 15.9 to 2.6 million years ago.
Wet collection: Or wet specimens, aka specimens preserved in liquid chemicals.
Pelagic coronuline barnacles: A type of marine invertebrate with a hard skeleton related to crabs and lobsters.
Later Stone Age: The prehistoric age is associated with the advent of modern human behaviour in Africa, thought to have occurred between 50,000 and 39,000 years ago.
Middle Stone Age: The prehistoric age considered to have run from 280,000 years ago to around 50–25,000 years ago.
Middens: Dumps of domestic waste that consist of everything from animal bone to human excrement and, in this case, shells.