A video captured in the coastal waters of Cape Town, South Africa, shows a rare interaction between a seal and its prey. While the bursts of ink clouds look like the seal is grappling with an enormous squid, the explosive escapee is in fact a dwarf sperm whale (Kogia sima), which are capable of releasing a "smoke bomb" of dark liquid when under attack.
Dwarf sperm whales occupy temperate and tropical marine habitats and are particularly partial to a continental shelf or slope where the seafloor is closer to the surface. They’re a small variety of whale at a maximum length of around 2.7 meters (8 foot 10 inches) and are grey in color with a chunky body and short, squat head. As well as employing the defense strategies of a squid, dwarf sperm whales eat squid, hunting them in small pods of up to four whales.
As a modest-sized cetacean, they’re preyed upon by their larger cousins, the orcas, as well as great white sharks and even large seals, as seen in the video. When under attack dwarf sperm whales have adapted a novel defense technique, as they eject a cloud of red-brown fluid into the water, obscuring themselves from view and confusing their attacker much like squid.
In the video, a dwarf sperm whale can be seen fleeing as a predatory seal zooms after it in pursuit. The chase is suddenly immersed in a reddish-brown cloud as the whale inks in an attempt to confuse the seal. This dark fluid is ejected from the whale’s intestine, and they can release more than 11 liters (3 gallons) of it when under attack.
The video is rare because dwarf sperm whales are elusive. Though they spend most of their time in the shallows, they’re shy and steer clear of boats and swimmers. When they surface, little of them is visible above the water and they sink vertically rather than diving with their tails in the air, making it hard to spot one breaking the surface.
"This 'inking' behavior has been documented before," said cetacean acoustician Karlina Merkens to ScienceAlert, "but it has been observed very rarely, and probably never seen and recorded in shallow water like this before."
A report from SA People indicated the chase ended badly for the whale, who likely found itself so close to shore due to illness. Unable to effectively use echolocation in a noisy harbor location, the stranded and injured animal was later recovered by officials, but due to its significant injuries the decision was made for the whale to be killed.