Strikingly coloured in grey hues, black and flashes of white, the blunt-nosed Heaviside’s dolphins are lookers! With a similar colouring to their orca foes, these small cetaceans have chunky 1.7-metre bodies that tip the scale at 60 – 75 kg. They become sexually mature between ages 5 and 9 and the female’s pregnancy every two to three years lasts for about 11 months.
Cephalorhynchus heavisidii was actually named after Captain Arthur Haviside who brought a specimen from Namibia to the UK early in the 19th century. But when the name was once misspelled Heaviside (after prominent surgeon John Heaviside), that name stuck.
Exclusive to 1 600 km along the African coastline shallows, these dolphins revel in temperatures of 9 -19°C. That’s why they tend to stick around in the cold waters of the West Coast’s Benguela current. So much so that some populations don’t even bother migrating. Pods of three are most common, but sometimes they party it up in pods of 5 – 17. Meal-wise, hake gets the thumbs-up, followed by goby, horse mackerel, octopus and squid.
Despite being known as shy, they actually do approach boats sometimes, bow-riding for several hours. But their acrobatic displays are somethin’ else: jumping vertically into the air, turning and falling back in without so much as a splash.
Heaviside’s dolphins are one of 13 species of toothed whales that have lost the ability to produce whistles for communication. Instead, when hunting, they use very high-frequency echolocation clicks to avoid detection by orcas who prey on them. Alas, when socialising they use lower frequency clicks. Risky business indeed, because orcas can home in on these sounds.
Ref: us.whales.org; deepoceanfacts.com
