Monday, February 2, 2009
Dolphins prepare Cuttlefish like perfect chefs
Prey handling of giant cuttlefish (Sepia apama) by Indo-Pacific bottlenose dolphin (Tursiops aduncus).
Prey: (a) pinned to substrate and killed; (b) lifted towards surface; (c) beaten with snout to release ink; (d) consumed whole.
In this one year old post we discovered how unexpectedly dolphins can be as romantic as (some) human beings seeing that english scientists discovered that male dolphins court their females bringing to them bunches of seaweeds in the same way that humans do with bunches of flowers.
Today we discover another fascinating skill of these amazing animals: They are able to prepare the cuttlefish they prey, like perfect chefs, draining off the ink and removing the cuttlebone. Given that they can't wield a knife or cleaverthis do is an impressive job!
The complex manoeuvre start even before, with the catching and killing of the cuttlefish: the scientists observed a wild Indo-Pacific bottlenose dolphin repeatedly performing a complex set of manoeuvres in the Spencer Gulf off South Australia. First, on spotting her prey, the female flushed a cuttlefish out of the dense weeds where they generally hide, into an open area with clear visibility. Adopting a vertical pose, head down and tail up, she pinned it to the sandy sea floor with her snout.
With a flick of her powerful tail, the dolphin then killed the fish with a rapid downward thrust that broke the cuttlebone. Divers who were watching heard a "loud click" as the bone snapped, the research team reported in the online science and medical journal PLoS ONE.
Next, the dolphin expelled the toxic black ink that cuttlefish squirt at predators when attacked, lifting the dead fish high in the water and repeatedly whacking it with her snout to release thick clouds of ink. Finally, it was time to get rid of the large, hard bone. The dolphin dived back down to the sea floor, where she scraped the fish along the sand, stripping off the skin until the bone popped out.
The whole manoeuvre can be seen in the picture above or, more clearly, in the drawing below.
Stages of prey handling of giant cuttlefish (Sepia apama) by Indo-Pacific bottlenose dolphin (Tursiops aduncus).
Prey: (a) flushed from algal cover to open substrate, b) pinned to substrate and killed; (c) lifted towards surface; (d) beaten with snout to release ink; (e) returned to substrate, inverted and forced along the sand to remove skin layer and release cuttlebone, (f) consumed whole.
For more info check PLoS ONE article
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