Comparison To Mammalian Milk
Crop milk bears little resemblance to mammalian milk, being a semi-solid substance somewhat like pale yellow cottage cheese. It is extremely high in protein and fat and contains more of it than cow or human milk. It has also been shown to contain anti-oxidants and immune-enhancing factors. Like mammalian milk, crop milk contains IgA antibodies. It also contains some bacteria. Unlike mammals, where the milk is an emulsion, pigeon crop milk consists of a suspension of protein rich and fat rich cells that proliferate and detach from the lining of the crop. In pigeons and flamingoes, both male and female adult produce crop milk and share in the feeding and care of the young. In penguins only the males lactate. Lactation in birds is also controlled by prolactin, the same hormone in mammals.
Read more about this topic: Crop Milk
Famous quotes containing the words comparison, mammalian and/or milk:
“Away with the cant of “Measures, not men!”Mthe idle supposition that it is the harness and not the horses that draw the chariot along. No, Sir, if the comparison must be made, if the distinction must be taken, men are everything, measures comparatively nothing.”
—George Canning (1770–1827)
“Specialization is a feature of every complex organization, be it social or natural, a school system, garden, book, or mammalian body.”
—Catharine R. Stimpson (b. 1936)
“A cow does not know how much milk it has until the milkman starts working on it. Then it looks round in surprise and sees the pail full to the brim. In the same way a writer has no idea how much he has to say till his pen draws it out of him. Thoughts will then appear on the paper that he is amazed to find that he possessed. “How brilliant!” he says to himself. “I had no idea I was so intelligent.” But the reader may not be so im pressed.”
—Gerald Branan (1894–1987)