Newly released drone footage captures the dramatic moment a pod of Australian humpback dolphins rapidly swim toward a riverbank in an attempt to capture prey.
The video was recorded at the Fitzroy River, one of Queensland’s largest catchments, and shows the “risky” behavior known as stranding or beaching. Dr Daniele Cagnazzi of Southern Cross University has been studying humpback dolphins in Central Queensland for more than a decade and notes that the hunting strategy can be a potentially dangerous method as it runs the risk of an individual dolphin stranding themself in the process.
“Strand feeding occurs where dolphins patrol the mud banks in search of prey; once the prey has been localized a dolphin swims at high speed toward the shore, catches the fish in its mouth and remains stranded for a short time before sliding gently back into the water,” said Cagnazzi in a statement.
“This type of feeding is very risky, as dolphins run the risk of remaining stranded, however, since this behavior is routinely repeated it must provide an important proportion of their daily feeding needs – dolphins must consume 4 to 6 percent of their own body weight in fish each day.”
Dolphins are highly intelligent animals and have been observed around the world using various feeding strategies to capture prey. In Florida, dolphins are known to create “nets” made of mud in order to trap fish while their larger cetacean cousins, killer whales, have been documenting giving white sharks a “karate chop” of death. In Queensland, the pinkish colored dolphins are the only known group to practice this hunting technique in the Fitzroy River. It is unclear where they learned the behavior or whether it is passed down from mother to calf, but it appears that just one or two individuals will hunt at a given time while the rest of the pod remains nearby. Previous footage captured in 2014 was only the second time that it had been observed.
“This feeding only occurs at low tide when the mud banks are exposed, therefore, habitat modification change, increasing flood frequency and sedimentation may affect the ability of dolphins to strand feed to provide their daily food needs. This is something we will continue to monitor,” said Cagnazzi.
This pod of Sousa sahulensis are the relatively shy long-term residents of the Fitzroy River and are listed as “vulnerable” in Queensland. Australian humpback dolphins are inshore species found in northern Australia and Asia that depend on their nearshore habitats for food and shelter – both of which may face threats from climate change and its associated impacts.