A friend was musing about dinosaur penises the other day. I stated with confident authority that dinosaurs had cloacae, rather than penises and vaginas.
He was very impressed that I would know so much about dinosaurs, the holes they passed stuff through, and the plural of the word cloaca.
Of course I had not researched this topic at all. I had pretty much just pulled this idea out of one of the holes that I pass stuff through, but I was happy to accept the reverence that my higher “knowledge” had won me.
So what’s the Straight Dope on dinosaurs and their gear???
Even if the female has a cloaca, the male still has a penis.
I was under the impression that they thought dinosaurs, despite controversies about endothermy vs. exothermy, were still very lizard-like in most ways, and had the cloaca and penis system. I might be completely wrong. Despite being a big dinosaur fan, I don’t recall this coming up in my reading.
For what it’s worth, there’s a picture of dinosaurs having sex in William Stout’s book Dinosaurs (There’s also one of a dinosaur pooping, for you completists). He tried to keep up with the latest research, so I assume his pioctuere shows what current thought was on the topic.
The movie Caveman shows Jack Gilford as a caveman unintentionally stroking a T. Rex’s penis – the only time a dinosaur sex organ has appeared in a movie, as far as I know. I wouldn’t take its appearance as canonical, though.
All male reptiles (that is, non-avian ones), except the Tuatara, have penises. This includes crocodilians, which are the most closely related non-avian reptiles to dinosaurs. And a number of birds, which are descended from dinosaurs, including more primitive groups such as ostriches and other ratites and ducks, have penises. Other birds most likely secondarily lost their penises evolutionarily because of the need to reduce weight for flight. I see no reason to think that dinosaurs would not have had penises.
Depending on their evolutionary affinity with lizards and snakes, dinosaurs may have even been equipped with two. Snakes and lizards have a pair called hemipenes. They only use one at a time.
Incidentally, crocodilian and bird penises are quite different from mammalian ones, and are not homologous. They are usually kept inside the body, and only everted through the cloacal opening when in use. Semen does not pass through a urethra (which they of course lack) but instead along a groove on the penis.
It might be worth noting that what we have for dinosaur fossils are almost exclusively “hard parts” – bones and teeth, and no jokes about hard-ons, please! There are only a few fossils where any part of the soft tissue (skin, internal organs, and so on) have been preserved at all, and none of them, AFAIK, happen to have preserved the sex organs.
For the record, in terms of cladistics, the Amniotes (everything which has embryos supported in an amnion, the “bag of waters,” whether egg-laying or live-bearing, and equivalent to the old groups of reptiles, birds, and mammals) are broken down into:
Anapsids: a few primitive reptiles and the turtles Synapsids: sailbacks and their allies, mammal-like reptiles, and mammals Lepidosaurs: snakes, lizards, the tuatara and its extinct relatives, ichthyosaurs, plesiosaurs, and all their kin Archosaurs: dinosaurs, flying reptiles, crocodilians, and birds, along with a few other minor extinct groups
While a thoroughgoing cladist would insist on redefining things to distinguish a few genera or families as “outgroups” to the above, it’s a pretty clear four-part distinction going back to the earliest amniote forms, which allows for differentiating all the major living and extinct amniote forms that anyone not a specialist has ever heard of.
The English plural of penis is penises. The Latin plural of penis is penes. Take your pick. I usually prefer to use an English plural if one is available.
You, however, are not allowed to say either. You must refer to them as “dinosaur dinguses”.
There is a bone called a chevron at the base of crocodiles’ tail that the penis is anchored to; some dinosaurs have the same bone. Therefore, there’s a good chance dinos did have penises. Google is clogged with penis stuff, so this is the best cite I can find : Link
No, dingi. Words ending in -us are generally second declension, and have a plural ending in -i. Words ending in -is, despite sounding very similar in English pronounciation, are generally third declension, and have a plural ending in -es (there are many other possible singular endings in the third declension, as well).
“Dingus” being a pseudo-Latinate English word, there is no Latin plural, and the English plural is a regular “dinguses.”
And while “penises” is equally correct with “penes” (and substantially clearer in speech that you’re talking about more than one male organ), the proper plural when you’re making reference to the bifurcated male genitalia of snakes and lizards is “hemipenes” – being a technical term, it appears to require the Latin plural in English.
