Humpback whale stranding, Kei Mouth (South Africa)

Yesterday museum scientist Kevin Cole went out to the small coastal town of Kei Mouth to sample a 12.3 m male humpback whale which had stranded during the night after being reported seen drifting live at 19h20 on Saturday 30th March 2019. Video footage revealed a very emaciated individual with labored breathing.


Easily identified by the wing-like flippers (in this case measuring 3.67 m)  and a head comprising about 30% of the body length  with the upper surface of the snout, chin and mandibles  noticeably covered in raised tubercles which can present with a single hair.


Baleen plates are attached to the upper jaw and humpback whales have an average of 325 plates in each series (both sides of the jaw with the longest measuring between 80-100 cm).



Baleen plates still attached to the gum which has dislodged from the jaw

Key identification features for this species are the large flippers (in some cases reaching a length almost 1/3 the total body length of the animal), the dorsal fin set 2/3 back on the whale, the papillae on the rostrum and the scalloped trailing edge of the flukes (tail).


Humpback whales move between the summer feeding grounds of the Antarctic to the winter breeding grounds further north (more tropical) passing the East London coast as the begin their migration in April (having reached the Knysna coast at this time).  These seasonal migrations are up to 16 000 km’s in range.

These whales can grow to a length of 15 m with females being larger than males.

As the whale decomposes and bloats there can be an expression of the genitalia in males as illustrated below (penis of the male humpback whale).


They have a characteristic V-shaped bushy blow. Flipper slapping, breaching and lob tailing are important behavioral traits for communication. Diving can last for 3-15 minutes and sometimes up to 40 minutes reaching depths of 150 m.

Pictured below is the left eye of the male humpback whale (18 cm in length).


Hundreds of whale lice were noted on the specimen (an external parasite). These little crustaceans feed on the skin of the whale and are mostly found in crevices in the folds of the skin. They live entirely on the whale and certain species only live on particular whale species such as the ones illustrated on this humpback whale.


The stranded specimen also had three shark bites to the body (tail end). These were most probably inflicted while the ill, slow moving animal was still alive. They would not have been the cause of death.


The length of the blow-hole was measured at 46 cm with a width of 24 cm (illustrated below).


Blubber, skin and muscle samples were taken for further analysis as well as a sample of baleen. These will be sent to Dr Greg Hofmeyr at the Port Elizabeth Museum (Bayworld).

This is the second humpback whale stranding in the area within 6 months (the last being a short distance away at Cape Morgan). The stranding was reported to the museum by Mrs Barbara Strydom of Kei Mouth and Ms Siani Tinley of the Buffalo City Metro (Senior Manager, Zoological and Marine Services).

Mr Bryan Church (Strandloper Trail Manager) has been a great help in documenting the whale and assisting the museum in liaising with authorities at the site with regard to the disposal of the carcass. The Great Kei Municipality has the permitted authority to remove the carcass to be disposed of at a land-fill site.


Museum scientist Kevin Cole points to one of three shark bite marks on the stranded humpback whale at Kei Mouth. The other two can be seen closer to the tail.

Reference: Whales and dolphins of the southern African subregion by Peter B. Best

About East London Museum Science

Conservation Biologist East London Museum South Africa
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