Thursday 7 April 2016

Wildlife in False Bay - Southern Right Whales

southern right whales
Southern right whale with her calve.
These intelligent and inquisitive animals are seen from along the shores of the southern tip of Africa. Southern right whales are one of three endangered species belonging to the genus Eubalanea. Considered a marine mammal, because of giving birth to live young, producing milk for their calves, being warm blooded and breathing air, these enormous animals can weigh as much as 8 fully grown African elephants and reach 16 metres in length.

The southern right whale, like other right whales, have callosities that appear white due to colonies of cyamids (whale lice) and barnacles. Dark grey or black in colour, these giant marine animals are without a dorsal fin but are able to swim by using their short and wide pectoral fins that aid in steering while their rear flukes propel them forward through the ocean. They have a long and arching mouth that begins above their eye, adding character to their gigantic profile.

Habitat

The southern right whale migrates to the coastal waters of South Africa, in the winter months and can be seen from the shore in False Bay, between June to October. These magnificent marine mammals form small social groups of about six individual and related whales. Whales have a strong maternal connection to the locations they were born in and are known to return to these very locations every 3 years.

southern right whales
Arched mouth showing baleen plates.
Diet

Whales usually search for food on the surface of water but will on occasion dive for food. They mostly eat small plankton called copepods but also indulge in krill, mysids, plankton and other tiny crustaceans.

They do not possess teeth and instead have around 200 long baleen plates hanging from their upper jaw. These plates can reach over 2 metres in length and have a fringe of hair running down each side. As a whale swims along the surface of water into swarms of plankton they open their mouth in order to catch their food and then close their mouth, using their tongue to push the water out between the baleen plates while keeping their food in their mouth.

Behaviour

Southern right whales are wonderful animals that are social with other whales and dolphins and even enjoy interacting with humans. They seem aware of their enormous size and so are gentle with their movements when around humans and smaller animals of the sea. These whales are more active than the other two northern species of right whales and are known to approach boats out of curiosity.  

southern right whales
Breaching in False Bay.
Whales engage in a variety of behaviour in the water for play or as a form of a communication. Sailing is playful behaviour exclusive to southern right whales, usually seen off the coast of Argentina and South Africa, who use their raised flukes to catch the wind. The normal breathing pattern of a whale is referred to as blowing which involves making a sound by expelling air through their blowhole accompanied by a spray of water vapour. Lob-tailing is a form of communication used by whales and is the slapping of water using their flukes and tail in order to make a loud sound. Whales lift their heads and body vertically above the surface as water, known as spy-hopping, so as to see what is happening above water. Breaching is when a whale leaps out of the water in a back flip landing on either their side or back.

Reproduction

Being polyamorous by nature, female whales mate with up to 7 males during the breeding season from July to October and return the following year to give birth to a single calve. Males do not fight amongst one another or experience feelings of jealousy when it comes to pairing up with females for mating.  

The female whales work on a 3-year cycle which includes one year of carrying a calve, a year taking care of their new-born and one year recovering and rebuilding their food reserves before starting the cycle once again.

Calves are usually born a dark-bluish colour but in some cases, about 4% of calves are born white. Due to a sex-linked genetic trait, all the calves born white are male and their colour darkens with age.

Did you know?

Whales can produce a variety of low frequency sounds (less than 1 000 Hz) to communicate with other whales. These sounds are made up of moans, growls, pulses and belch like noises. 

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