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!

Back to whales again! In general, cetaceans have no protruding udders like cows. Whale mammaries are two long and fairly flat organs inclined to each other at a slight angle. Their tips are not far from the umbilicus, and the average dimensions in "resting" Rorqual cows are about 7ft. by 2 ft. 6 in. by 2 1/4 in.

It is surprising how many people are not aware, even today, that plants reproduce bisexually in many species. In fact the plants have been at it a long time. Algae first began to reproduce bisexually around 1,000,000,000 years ago. Considering that man has been copulating for a million years or so, the various species of algae score high on persistence. A freshwater algae (Ulothrix) is often used to illustrate the origin of gametes, i.e. the origin of sex cells. The elongated filament-body of the algae generates a number of small spores which have lost the

Roman snails are very keen on sex play prior to copulation. The preliminary courting can include extensive rocking to and fro, rearing up, and rhythmic oscillations. The sex play can also include what Wendt has termed "smacking kisses". After all these happy preliminaries the actual copulation itself may last for several minutes.

It will hardly come as a surprise that elephants and whales have big testes: these creatures are after all weighty fellows. In one adult elephant the two testes weighted 1.8 kg. and 2.2 kg. respectively, and the left one measured 175mm. x 150mm. x 115mm. in length, width, and thickness. It has been noted that bladder urine collected as much as twelve hours after death contained a large number of motile sperm. The really massive testes however

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.

The clitoris of the female whale is about 8 cm. long. Its apex is said to be "triloped" and is directed backwards. The whale clitoris, in common with the other sex organs of the largest cetaceans, are the biggest of any animal.

Many other species have organs large for their body size, and in a number of species there is a long clitoris. We have already noted the large clitoris in the hyaena and the spider monkey. It is also surprisingly long in the mole (in the non-breeding season it is as long as the penis). In cats and civets the clitoris is a

We have already noted some rather surprising preliminaries or accompaniments to insect coitus, but the mechanics of the coital act itself is sometimes equally remarkable. In bed bug copulation the sperm is placed in a pocket in the cuticle on the ventral surface of the female abdomen, whereupon the sperm actually makes its way through the body wall and reaches the ovaries via the blood stream. In many species - some bed bugs (as well

One of the main problems in bisexual reproduction is how to get the sex cells together. Or - looked at another way - the whole business of sex is so pleasurable for human beings that the main problem is to keep the sex cells apart, i.e. to achieve effective contraception. In its earliest stages biological evolution managed to contrive a variety of means whereby the "male" and "female" components could come together for reproduction: the penis and vagina arrangement was "late" in the evolutionary scale. The earliest species lived in water and simply

Birds and mammals are not known to have produced parthenogenetic populations in the wild. But, oddly enough, experimenters working with turkeys have had considerable success in producing parthenogenetic strains. Using more than 42,000 eggs American scientists were able to increase the number of eggs "which started to develop" from 16.7 per cent in 1952 to 41.7 per cent in 1959. This improvement was a result of selective breeding. Birds