Evolution: bird beak sixth sense (Evolution)

by David Turell , Wednesday, December 02, 2020, 01:18 (1451 days ago) @ David Turell

It is remote sensing of prey:

https://www.newscientist.com/article/2261317-bird-beak-extra-sense-evolved-more-than-70...

:An organ that allows certain birds to detect the movement of hidden prey by plunging their beaks into the ground was also present in early birds 70 million years ago, and probably first appeared in their dinosaur ancestors.

"Special “remote touch” sensory receptors known as Herbst corpuscles, which are found within densely-packed pits in the beak’s tip, help birds detect the movement of worms in soil or small fish in water – even several centimetres away from the bird’s beak. This effectively gives birds a “sixth sense”, according to Carla du Toit at the University of Cape Town in South Africa and her colleagues.

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"By examining specimens of modern birds, the researchers identified distinct pitting patterns in the beak associated with Herbst corpuscles, says du Toit. The team then found those same patterns in lithornithid fossil beaks, which suggests that lithornithids had the same sensory abilities and were probe-foraging birds.

"The discovery makes sense, because Herbst corpuscles are found in both palaeognaths such as kiwis, and in neognaths such as ibises. The two groups separated from one another more than 70 million years ago, which would suggest Herbst corpuscles evolved in the common ancestor of both bird groups.

"In fact, the sensory structures might have evolved in dinosaurs, says du Toit. A “sixth sense” feature might have helped carnivorous theropods such as Neovenator find prey by probing their snouts into mud or murky water, she says."

Comment: If the prey is remote, how does the animal know what it is looking for? Sems it had to be designed for use.