Letter: In Brief

Sir: The article "I think, therefore I'm a chimp" (29 January) suggests that only children over the age of 18 months, the higher apes and possibly dolphins display self-consciousness when confronted with a mirror. But I have a house-hen who regularly uses a floor-length mirror in her preening. Twisting and turning as she preens, she checks the effect in places otherwise hard to see, ensuring that every feather is presented to a high standard. I presume that she is self-conscious as well as vain.

DAVID MARTIN

York