Many birds do not have penises, and mate by touching genital openings -- called a "cloacal kiss". But some species of duck and ostriches do have a penis.

The longest bird penis discovered belongs to the Argentine lake duck (Oxyura vittata), measured at around 42.5cm, an astonishing dimension matches the length of an adult male, and compares to the length of an ostrich penis. If the Argentine lake duck were human, we could boast 5 - 6-foot penises!

See:

• Largest human penis
• Largest penis in animal kingdom

We all know that men are supposed to worry endlessly about penis size. In popular mythology a small organ is still thought to signal a totally inadequate lover. All the best books tell us that this idea is absurd but nonetheless the notion persists.

In the Dr. Jacobus survey definite penis size differences on a basis of race were detected. The largest Arab penises were found to be between eight and ten inches; but it was among the Muslim Sudanese that Jacobus found "the most developed phallus" - notably "one of the maximum dimensions, being nearly 12 in. in length, by a diameter of 2- in."

The hardy researcher remarked that this was "a terrific machine" - "more likely the penis of a donkey than of a man." He concluded that the "Sudanese Negro possesses the largest genital

The Kinsey group compiled data on penis size for the detailed report on sex offenders. Various classes of offenders were asked to estimate their penis length on the ventral surface from the abdomen to the tip of the penis.

Penis lengths for various groups were found to average 6.3 to 6.5 in. It was found that only one group -- "the aggressors v. minors" - reported an above-average length penis (around 6.75 in.). It was pointed out that contrary to expectation the estimated penis length of the exhibitionists was not unusual.

Vast numbers of men - in one estimate the greater majority - think that they have a penis much below the average in size. Perhaps they should console themselves with the thought that many men have extremely diminutive organs. Pomeroy states that the smallest penis encountered in the Kinsey surveys was 1 in. long In the Forum study the smallest erect penis was found to be 4.75 in. in length, quite large compared with many of the specimens that do exist. There are instances reported in the medical literature of penises that do not exceed 1 cm.

In the Jacobus survey the Hindu man was reckoned to have a penis that only averaged around 4 inches, a much smaller figure than for the other races investigated. In the Chartham survey the smallest organs in the various nationality groups were as follows: English - 2¾ in.; West German - 3½ in.; Negro - 4 in.; French 3½ in.; Danish - 5 in.; American - 3½ in.; and Swedish - 5 in. As we have already suggested, with the groups being rather small no racial conclusions can be drawn.

In fiction and legend the human penis can be any size.

Malinowski wrote of the Legend of Inuvayla'u, who was the head of his clan and possessed of a remarkably long organ. When the women of the tribe were cleaning the ground or weeding he would stand behind a fence and push his penis through a convenient aperture.

In a seventeenth-century Chinese tale Jou-pu-t'uan, there is an account of a penis transplant, or, perhaps more accurately, a penis graft. A Scholar inquires of the Master of Medicine how a gigantic organ can be acquired. One technique, as carefully explained, is to make use of the erect organ of a dog. It is arranged for the dog and bitch to copulate; in the midst of the act the Master of Medicine cuts off the penis of the dog and, slicing it up, inserts the parts into the incised organ of the man requiring a larger member-"With luck, there will be a perfect

It is appropriate that large animals should have large genital organs.

The penis of the hippopotamus and elephant can be several feet in length, and uses have some times been found for such weighty organs other than simple reproduction - the pizzle, for instance, formerly used for flogging, was in fact a bull's penis. Marshall's "Physiology of Reproduction" notes that the elephant penis is around 150 cm. in length, a third of which is formed by the pendulous portion.